Changes in libcfa/src/concurrency/ready_queue.cfa [4479890:46bbcaf]

File:

• libcfa/src/concurrency/ready_queue.cfa (modified) (7 diffs)

libcfa/src/concurrency/ready_queue.cfa

@@ -20 +20 @@
 
 
+// #define USE_RELAXED_FIFO
+// #define USE_WORK_STEALING
+// #define USE_CPU_WORK_STEALING
 #define USE_AWARE_STEALING
 
 #include "bits/defs.hfa"
 #include "device/cpu.hfa"
-#include "kernel/cluster.hfa"
-#include "kernel/private.hfa"
-
-// #include <errno.h>
-// #include <unistd.h>
+#include "kernel_private.hfa"
+
+#include "stdlib.hfa"
+#include "limits.hfa"
+#include "math.hfa"
+
+#include <errno.h>
+#include <unistd.h>
+
+extern "C" {
+        #include <sys/syscall.h>  // __NR_xxx
+}
 
 #include "ready_subqueue.hfa"
@@ -40 +50 @@
 #endif
 
+// No overriden function, no environment variable, no define
+// fall back to a magic number
+#ifndef __CFA_MAX_PROCESSORS__
+        #define __CFA_MAX_PROCESSORS__ 1024
+#endif
+
+#if   defined(USE_AWARE_STEALING)
+        #define READYQ_SHARD_FACTOR 2
+        #define SEQUENTIAL_SHARD 2
+#elif defined(USE_CPU_WORK_STEALING)
+        #define READYQ_SHARD_FACTOR 2
+#elif defined(USE_RELAXED_FIFO)
+        #define BIAS 4
+        #define READYQ_SHARD_FACTOR 4
+        #define SEQUENTIAL_SHARD 1
+#elif defined(USE_WORK_STEALING)
+        #define READYQ_SHARD_FACTOR 2
+        #define SEQUENTIAL_SHARD 2
+#else
+        #error no scheduling strategy selected
+#endif
+
 static inline struct thread$ * try_pop(struct cluster * cltr, unsigned w __STATS(, __stats_readyQ_pop_t & stats));
 static inline struct thread$ * try_pop(struct cluster * cltr, unsigned i, unsigned j __STATS(, __stats_readyQ_pop_t & stats));
 static inline struct thread$ * search(struct cluster * cltr);
+static inline [unsigned, bool] idx_from_r(unsigned r, unsigned preferred);
+
+
+// returns the maximum number of processors the RWLock support
+__attribute__((weak)) unsigned __max_processors() {
+        const char * max_cores_s = getenv("CFA_MAX_PROCESSORS");
+        if(!max_cores_s) {
+                __cfadbg_print_nolock(ready_queue, "No CFA_MAX_PROCESSORS in ENV\n");
+                return __CFA_MAX_PROCESSORS__;
+        }
+
+        char * endptr = 0p;
+        long int max_cores_l = strtol(max_cores_s, &endptr, 10);
+        if(max_cores_l < 1 || max_cores_l > 65535) {
+                __cfadbg_print_nolock(ready_queue, "CFA_MAX_PROCESSORS out of range : %ld\n", max_cores_l);
+                return __CFA_MAX_PROCESSORS__;
+        }
+        if('\0' != *endptr) {
+                __cfadbg_print_nolock(ready_queue, "CFA_MAX_PROCESSORS not a decimal number : %s\n", max_cores_s);
+                return __CFA_MAX_PROCESSORS__;
+        }
+
+        return max_cores_l;
+}
+
+#if   defined(CFA_HAVE_LINUX_LIBRSEQ)
+        // No forward declaration needed
+        #define __kernel_rseq_register rseq_register_current_thread
+        #define __kernel_rseq_unregister rseq_unregister_current_thread
+#elif defined(CFA_HAVE_LINUX_RSEQ_H)
+        static void __kernel_raw_rseq_register  (void);
+        static void __kernel_raw_rseq_unregister(void);
+
+        #define __kernel_rseq_register __kernel_raw_rseq_register
+        #define __kernel_rseq_unregister __kernel_raw_rseq_unregister
+#else
+        // No forward declaration needed
+        // No initialization needed
+        static inline void noop(void) {}
+
+        #define __kernel_rseq_register noop
+        #define __kernel_rseq_unregister noop
+#endif
+
+//=======================================================================
+// Cluster wide reader-writer lock
+//=======================================================================
+void  ?{}(__scheduler_RWLock_t & this) {
+        this.max   = __max_processors();
+        this.alloc = 0;
+        this.ready = 0;
+        this.data  = alloc(this.max);
+        this.write_lock  = false;
+
+        /*paranoid*/ verify(__atomic_is_lock_free(sizeof(this.alloc), &this.alloc));
+        /*paranoid*/ verify(__atomic_is_lock_free(sizeof(this.ready), &this.ready));
+
+}
+void ^?{}(__scheduler_RWLock_t & this) {
+        free(this.data);
+}
+
+
+//=======================================================================
+// Lock-Free registering/unregistering of threads
+unsigned register_proc_id( void ) with(*__scheduler_lock) {
+        __kernel_rseq_register();
+
+        bool * handle = (bool *)&kernelTLS().sched_lock;
+
+        // Step - 1 : check if there is already space in the data
+        uint_fast32_t s = ready;
+
+        // Check among all the ready
+        for(uint_fast32_t i = 0; i < s; i++) {
+                bool * volatile * cell = (bool * volatile *)&data[i]; // Cforall is bugged and the double volatiles causes problems
+                /* paranoid */ verify( handle != *cell );
+
+                bool * null = 0p; // Re-write every loop since compare thrashes it
+                if( __atomic_load_n(cell, (int)__ATOMIC_RELAXED) == null
+                        && __atomic_compare_exchange_n( cell, &null, handle, false, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST)) {
+                        /* paranoid */ verify(i < ready);
+                        /* paranoid */ verify( (kernelTLS().sched_id = i, true) );
+                        return i;
+                }
+        }
+
+        if(max <= alloc) abort("Trying to create more than %ud processors", __scheduler_lock->max);
+
+        // Step - 2 : F&A to get a new spot in the array.
+        uint_fast32_t n = __atomic_fetch_add(&alloc, 1, __ATOMIC_SEQ_CST);
+        if(max <= n) abort("Trying to create more than %ud processors", __scheduler_lock->max);
+
+        // Step - 3 : Mark space as used and then publish it.
+        data[n] = handle;
+        while() {
+                unsigned copy = n;
+                if( __atomic_load_n(&ready, __ATOMIC_RELAXED) == n
+                        && __atomic_compare_exchange_n(&ready, &copy, n + 1, true, __ATOMIC_SEQ_CST, __ATOMIC_SEQ_CST))
+                        break;
+                Pause();
+        }
+
+        // Return new spot.
+        /* paranoid */ verify(n < ready);
+        /* paranoid */ verify( (kernelTLS().sched_id = n, true) );
+        return n;
+}
+
+void unregister_proc_id( unsigned id ) with(*__scheduler_lock) {
+        /* paranoid */ verify(id < ready);
+        /* paranoid */ verify(id == kernelTLS().sched_id);
+        /* paranoid */ verify(data[id] == &kernelTLS().sched_lock);
+
+        bool * volatile * cell = (bool * volatile *)&data[id]; // Cforall is bugged and the double volatiles causes problems
+
+        __atomic_store_n(cell, 0p, __ATOMIC_RELEASE);
+
+        __kernel_rseq_unregister();
+}
+
+//-----------------------------------------------------------------------
+// Writer side : acquire when changing the ready queue, e.g. adding more
+//  queues or removing them.
+uint_fast32_t ready_mutate_lock( void ) with(*__scheduler_lock) {
+        /* paranoid */ verify( ! __preemption_enabled() );
+
+        // Step 1 : lock global lock
+        // It is needed to avoid processors that register mid Critical-Section
+        //   to simply lock their own lock and enter.
+        __atomic_acquire( &write_lock );
+
+        // Make sure we won't deadlock ourself
+        // Checking before acquiring the writer lock isn't safe
+        // because someone else could have locked us.
+        /* paranoid */ verify( ! kernelTLS().sched_lock );
+
+        // Step 2 : lock per-proc lock
+        // Processors that are currently being registered aren't counted
+        //   but can't be in read_lock or in the critical section.
+        // All other processors are counted
+        uint_fast32_t s = ready;
+        for(uint_fast32_t i = 0; i < s; i++) {
+                volatile bool * llock = data[i];
+                if(llock) __atomic_acquire( llock );
+        }
+
+        /* paranoid */ verify( ! __preemption_enabled() );
+        return s;
+}
+
+void ready_mutate_unlock( uint_fast32_t last_s ) with(*__scheduler_lock) {
+        /* paranoid */ verify( ! __preemption_enabled() );
+
+        // Step 1 : release local locks
+        // This must be done while the global lock is held to avoid
+        //   threads that where created mid critical section
+        //   to race to lock their local locks and have the writer
+        //   immidiately unlock them
+        // Alternative solution : return s in write_lock and pass it to write_unlock
+        for(uint_fast32_t i = 0; i < last_s; i++) {
+                volatile bool * llock = data[i];
+                if(llock) __atomic_store_n(llock, (bool)false, __ATOMIC_RELEASE);
+        }
+
+        // Step 2 : release global lock
+        /*paranoid*/ assert(true == write_lock);
+        __atomic_store_n(&write_lock, (bool)false, __ATOMIC_RELEASE);
+
+        /* paranoid */ verify( ! __preemption_enabled() );
+}
+
+//=======================================================================
+// caches handling
+
+struct __attribute__((aligned(128))) __ready_queue_caches_t {
+        // Count States:
+        // - 0  : No one is looking after this cache
+        // - 1  : No one is looking after this cache, BUT it's not empty
+        // - 2+ : At least one processor is looking after this cache
+        volatile unsigned count;
+};
+
+void  ?{}(__ready_queue_caches_t & this) { this.count = 0; }
+void ^?{}(__ready_queue_caches_t & this) {}
+
+static inline void depart(__ready_queue_caches_t & cache) {
+        /* paranoid */ verify( cache.count > 1);
+        __atomic_fetch_add(&cache.count, -1, __ATOMIC_SEQ_CST);
+        /* paranoid */ verify( cache.count != 0);
+        /* paranoid */ verify( cache.count < 65536 ); // This verify assumes no cluster will have more than 65000 kernel threads mapped to a single cache, which could be correct but is super weird.
+}
+
+static inline void arrive(__ready_queue_caches_t & cache) {
+        // for() {
+        //      unsigned expected = cache.count;
+        //      unsigned desired  = 0 == expected ? 2 : expected + 1;
+        // }
+}
 
 //=======================================================================
 // Cforall Ready Queue used for scheduling
 //=======================================================================
-// void ?{}(__ready_queue_t & this) with (this) {
-//      lanes.data   = 0p;
-//      lanes.tscs   = 0p;
-//      lanes.caches = 0p;
-//      lanes.count  = 0;
-// }
-
-// void ^?{}(__ready_queue_t & this) with (this) {
-//      free(lanes.data);
-//      free(lanes.tscs);
-//      free(lanes.caches);
-// }
+unsigned long long moving_average(unsigned long long currtsc, unsigned long long instsc, unsigned long long old_avg) {
+        /* paranoid */ verifyf( currtsc < 45000000000000000, "Suspiciously large current time: %'llu (%llx)\n", currtsc, currtsc );
+        /* paranoid */ verifyf( instsc  < 45000000000000000, "Suspiciously large insert time: %'llu (%llx)\n", instsc, instsc );
+        /* paranoid */ verifyf( old_avg < 15000000000000, "Suspiciously large previous average: %'llu (%llx)\n", old_avg, old_avg );
+
+        const unsigned long long new_val = currtsc > instsc ? currtsc - instsc : 0;
+        const unsigned long long total_weight = 16;
+        const unsigned long long new_weight   = 4;
+        const unsigned long long old_weight = total_weight - new_weight;
+        const unsigned long long ret = ((new_weight * new_val) + (old_weight * old_avg)) / total_weight;
+        return ret;
+}
+
+void ?{}(__ready_queue_t & this) with (this) {
+        #if defined(USE_CPU_WORK_STEALING)
+                lanes.count = cpu_info.hthrd_count * READYQ_SHARD_FACTOR;
+                lanes.data = alloc( lanes.count );
+                lanes.tscs = alloc( lanes.count );
+                lanes.help = alloc( cpu_info.hthrd_count );
+
+                for( idx; (size_t)lanes.count ) {
+                        (lanes.data[idx]){};
+                        lanes.tscs[idx].tv = rdtscl();
+                        lanes.tscs[idx].ma = rdtscl();
+                }
+                for( idx; (size_t)cpu_info.hthrd_count ) {
+                        lanes.help[idx].src = 0;
+                        lanes.help[idx].dst = 0;
+                        lanes.help[idx].tri = 0;
+                }
+        #else
+                lanes.data   = 0p;
+                lanes.tscs   = 0p;
+                lanes.caches = 0p;
+                lanes.help   = 0p;
+                lanes.count  = 0;
+        #endif
+}
+
+void ^?{}(__ready_queue_t & this) with (this) {
+        #if !defined(USE_CPU_WORK_STEALING)
+                verify( SEQUENTIAL_SHARD == lanes.count );
+        #endif
+
+        free(lanes.data);
+        free(lanes.tscs);
+        free(lanes.caches);
+        free(lanes.help);
+}
 
 //-----------------------------------------------------------------------
-__attribute__((hot)) void push(struct cluster * cltr, struct thread$ * thrd, unpark_hint hint) with (cltr->sched) {
-        processor * const proc = kernelTLS().this_processor;
-        const bool external = (!proc) || (cltr != proc->cltr);
-        const bool remote   = hint == UNPARK_REMOTE;
-        const size_t lanes_count = readyQ.count;
-
-        /* paranoid */ verify( __shard_factor.readyq > 0 );
-        /* paranoid */ verify( lanes_count > 0 );
-
-        unsigned i;
-        if( external || remote ) {
-                // Figure out where thread was last time and make sure it's valid
-                /* paranoid */ verify(thrd->preferred >= 0);
-                unsigned start = thrd->preferred * __shard_factor.readyq;
-                if(start < lanes_count) {
-                        do {
-                                unsigned r = __tls_rand();
-                                i = start + (r % __shard_factor.readyq);
-                                /* paranoid */ verify( i < lanes_count );
-                                // If we can't lock it retry
-                        } while( !__atomic_try_acquire( &readyQ.data[i].lock ) );
+#if defined(USE_AWARE_STEALING)
+        __attribute__((hot)) void push(struct cluster * cltr, struct thread$ * thrd, unpark_hint hint) with (cltr->ready_queue) {
+                processor * const proc = kernelTLS().this_processor;
+                const bool external = (!proc) || (cltr != proc->cltr);
+                const bool remote   = hint == UNPARK_REMOTE;
+
+                unsigned i;
+                if( external || remote ) {
+                        // Figure out where thread was last time and make sure it's valid
+                        /* paranoid */ verify(thrd->preferred >= 0);
+                        if(thrd->preferred * READYQ_SHARD_FACTOR < lanes.count) {
+                                /* paranoid */ verify(thrd->preferred * READYQ_SHARD_FACTOR < lanes.count);
+                                unsigned start = thrd->preferred * READYQ_SHARD_FACTOR;
+                                do {
+                                        unsigned r = __tls_rand();
+                                        i = start + (r % READYQ_SHARD_FACTOR);
+                                        /* paranoid */ verify( i < lanes.count );
+                                        // If we can't lock it retry
+                                } while( !__atomic_try_acquire( &lanes.data[i].lock ) );
+                        } else {
+                                do {
+                                        i = __tls_rand() % lanes.count;
+                                } while( !__atomic_try_acquire( &lanes.data[i].lock ) );
+                        }
                 } else {
                         do {
-                                i = __tls_rand() % lanes_count;
-                        } while( !__atomic_try_acquire( &readyQ.data[i].lock ) );
-                }
-        } else {
+                                unsigned r = proc->rdq.its++;
+                                i = proc->rdq.id + (r % READYQ_SHARD_FACTOR);
+                                /* paranoid */ verify( i < lanes.count );
+                                // If we can't lock it retry
+                        } while( !__atomic_try_acquire( &lanes.data[i].lock ) );
+                }
+
+                // Actually push it
+                push(lanes.data[i], thrd);
+
+                // Unlock and return
+                __atomic_unlock( &lanes.data[i].lock );
+
+                #if !defined(__CFA_NO_STATISTICS__)
+                        if(unlikely(external || remote)) __atomic_fetch_add(&cltr->stats->ready.push.extrn.success, 1, __ATOMIC_RELAXED);
+                        else __tls_stats()->ready.push.local.success++;
+                #endif
+        }
+
+        static inline unsigned long long calc_cutoff(const unsigned long long ctsc, const processor * proc, __ready_queue_t & rdq) {
+                unsigned start = proc->rdq.id;
+                unsigned long long max = 0;
+                for(i; READYQ_SHARD_FACTOR) {
+                        unsigned long long ptsc = ts(rdq.lanes.data[start + i]);
+                        if(ptsc != -1ull) {
+                                /* paranoid */ verify( start + i < rdq.lanes.count );
+                                unsigned long long tsc = moving_average(ctsc, ptsc, rdq.lanes.tscs[start + i].ma);
+                                if(tsc > max) max = tsc;
+                        }
+                }
+                return (max + 2 * max) / 2;
+        }
+
+        __attribute__((hot)) struct thread$ * pop_fast(struct cluster * cltr) with (cltr->ready_queue) {
+                /* paranoid */ verify( lanes.count > 0 );
+                /* paranoid */ verify( kernelTLS().this_processor );
+                /* paranoid */ verify( kernelTLS().this_processor->rdq.id < lanes.count );
+
+                processor * const proc = kernelTLS().this_processor;
+                unsigned this = proc->rdq.id;
+                /* paranoid */ verify( this < lanes.count );
+                __cfadbg_print_safe(ready_queue, "Kernel : pop from %u\n", this);
+
+                // Figure out the current cpu and make sure it is valid
+                const int cpu = __kernel_getcpu();
+                /* paranoid */ verify(cpu >= 0);
+                /* paranoid */ verify(cpu < cpu_info.hthrd_count);
+                unsigned this_cache = cpu_info.llc_map[cpu].cache;
+
+                // Super important: don't write the same value over and over again
+                // We want to maximise our chances that his particular values stays in cache
+                if(lanes.caches[this / READYQ_SHARD_FACTOR].id != this_cache)
+                        __atomic_store_n(&lanes.caches[this / READYQ_SHARD_FACTOR].id, this_cache, __ATOMIC_RELAXED);
+
+                const unsigned long long ctsc = rdtscl();
+
+                if(proc->rdq.target == MAX) {
+                        uint64_t chaos = __tls_rand();
+                        unsigned ext = chaos & 0xff;
+                        unsigned other  = (chaos >> 8) % (lanes.count);
+
+                        if(ext < 3 || __atomic_load_n(&lanes.caches[other / READYQ_SHARD_FACTOR].id, __ATOMIC_RELAXED) == this_cache) {
+                                proc->rdq.target = other;
+                        }
+                }
+                else {
+                        const unsigned target = proc->rdq.target;
+                        __cfadbg_print_safe(ready_queue, "Kernel : %u considering helping %u, tcsc %llu\n", this, target, lanes.tscs[target].tv);
+                        /* paranoid */ verify( lanes.tscs[target].tv != MAX );
+                        if(target < lanes.count) {
+                                const unsigned long long cutoff = calc_cutoff(ctsc, proc, cltr->ready_queue);
+                                const unsigned long long age = moving_average(ctsc, lanes.tscs[target].tv, lanes.tscs[target].ma);
+                                __cfadbg_print_safe(ready_queue, "Kernel : Help attempt on %u from %u, age %'llu vs cutoff %'llu, %s\n", target, this, age, cutoff, age > cutoff ? "yes" : "no");
+                                if(age > cutoff) {
+                                        thread$ * t = try_pop(cltr, target __STATS(, __tls_stats()->ready.pop.help));
+                                        if(t) return t;
+                                }
+                        }
+                        proc->rdq.target = MAX;
+                }
+
+                for(READYQ_SHARD_FACTOR) {
+                        unsigned i = this + (proc->rdq.itr++ % READYQ_SHARD_FACTOR);
+                        if(thread$ * t = try_pop(cltr, i __STATS(, __tls_stats()->ready.pop.local))) return t;
+                }
+
+                // All lanes where empty return 0p
+                return 0p;
+
+        }
+        __attribute__((hot)) struct thread$ * pop_slow(struct cluster * cltr) with (cltr->ready_queue) {
+                unsigned i = __tls_rand() % lanes.count;
+                return try_pop(cltr, i __STATS(, __tls_stats()->ready.pop.steal));
+        }
+        __attribute__((hot)) struct thread$ * pop_search(struct cluster * cltr) {
+                return search(cltr);
+        }
+#endif
+#if defined(USE_CPU_WORK_STEALING)
+        __attribute__((hot)) void push(struct cluster * cltr, struct thread$ * thrd, unpark_hint hint) with (cltr->ready_queue) {
+                __cfadbg_print_safe(ready_queue, "Kernel : Pushing %p on cluster %p\n", thrd, cltr);
+
+                processor * const proc = kernelTLS().this_processor;
+                const bool external = (!proc) || (cltr != proc->cltr);
+
+                // Figure out the current cpu and make sure it is valid
+                const int cpu = __kernel_getcpu();
+                /* paranoid */ verify(cpu >= 0);
+                /* paranoid */ verify(cpu < cpu_info.hthrd_count);
+                /* paranoid */ verify(cpu * READYQ_SHARD_FACTOR < lanes.count);
+
+                // Figure out where thread was last time and make sure it's
+                /* paranoid */ verify(thrd->preferred >= 0);
+                /* paranoid */ verify(thrd->preferred < cpu_info.hthrd_count);
+                /* paranoid */ verify(thrd->preferred * READYQ_SHARD_FACTOR < lanes.count);
+                const int prf = thrd->preferred * READYQ_SHARD_FACTOR;
+
+                const cpu_map_entry_t & map;
+                choose(hint) {
+                        case UNPARK_LOCAL : &map = &cpu_info.llc_map[cpu];
+                        case UNPARK_REMOTE: &map = &cpu_info.llc_map[prf];
+                }
+                /* paranoid */ verify(map.start * READYQ_SHARD_FACTOR < lanes.count);
+                /* paranoid */ verify(map.self * READYQ_SHARD_FACTOR < lanes.count);
+                /* paranoid */ verifyf((map.start + map.count) * READYQ_SHARD_FACTOR <= lanes.count, "have %zu lanes but map can go up to %u", lanes.count, (map.start + map.count) * READYQ_SHARD_FACTOR);
+
+                const int start = map.self * READYQ_SHARD_FACTOR;
+                unsigned i;
                 do {
-                        unsigned r = proc->rdq.its++;
-                        i = proc->rdq.id + (r % __shard_factor.readyq);
-                        /* paranoid */ verify( i < lanes_count );
+                        unsigned r;
+                        if(unlikely(external)) { r = __tls_rand(); }
+                        else { r = proc->rdq.its++; }
+                        choose(hint) {
+                                case UNPARK_LOCAL : i = start + (r % READYQ_SHARD_FACTOR);
+                                case UNPARK_REMOTE: i = prf   + (r % READYQ_SHARD_FACTOR);
+                        }
                         // If we can't lock it retry
-                } while( !__atomic_try_acquire( &readyQ.data[i].lock ) );
-        }
-
-        // Actually push it
-        push(readyQ.data[i], thrd);
-
-        // Unlock and return
-        __atomic_unlock( &readyQ.data[i].lock );
-
-        #if !defined(__CFA_NO_STATISTICS__)
-                if(unlikely(external || remote)) __atomic_fetch_add(&cltr->stats->ready.push.extrn.success, 1, __ATOMIC_RELAXED);
-                else __tls_stats()->ready.push.local.success++;
-        #endif
-}
-
-__attribute__((hot)) struct thread$ * pop_fast(struct cluster * cltr) with (cltr->sched) {
-        const size_t lanes_count = readyQ.count;
-
-        /* paranoid */ verify( __shard_factor.readyq > 0 );
-        /* paranoid */ verify( lanes_count > 0 );
-        /* paranoid */ verify( kernelTLS().this_processor );
-        /* paranoid */ verify( kernelTLS().this_processor->rdq.id < lanes_count );
-
-        processor * const proc = kernelTLS().this_processor;
-        unsigned this = proc->rdq.id;
-        /* paranoid */ verify( this < lanes_count );
-        __cfadbg_print_safe(ready_queue, "Kernel : pop from %u\n", this);
-
-        // Figure out the current cache is
-        const unsigned this_cache = cache_id(cltr, this / __shard_factor.readyq);
-        const unsigned long long ctsc = rdtscl();
-
-        if(proc->rdq.target == MAX) {
-                uint64_t chaos = __tls_rand();
-                unsigned ext = chaos & 0xff;
-                unsigned other  = (chaos >> 8) % (lanes_count);
-
-                if(ext < 3 || __atomic_load_n(&caches[other / __shard_factor.readyq].id, __ATOMIC_RELAXED) == this_cache) {
-                        proc->rdq.target = other;
-                }
-        }
-        else {
-                const unsigned target = proc->rdq.target;
-                __cfadbg_print_safe(ready_queue, "Kernel : %u considering helping %u, tcsc %llu\n", this, target, readyQ.tscs[target].tv);
-                /* paranoid */ verify( readyQ.tscs[target].tv != MAX );
-                if(target < lanes_count) {
-                        const unsigned long long cutoff = calc_cutoff(ctsc, proc->rdq.id, lanes_count, cltr->sched.readyQ.data, cltr->sched.readyQ.tscs, __shard_factor.readyq);
-                        const unsigned long long age = moving_average(ctsc, readyQ.tscs[target].tv, readyQ.tscs[target].ma);
-                        __cfadbg_print_safe(ready_queue, "Kernel : Help attempt on %u from %u, age %'llu vs cutoff %'llu, %s\n", target, this, age, cutoff, age > cutoff ? "yes" : "no");
-                        if(age > cutoff) {
+                } while( !__atomic_try_acquire( &lanes.data[i].lock ) );
+
+                // Actually push it
+                push(lanes.data[i], thrd);
+
+                // Unlock and return
+                __atomic_unlock( &lanes.data[i].lock );
+
+                #if !defined(__CFA_NO_STATISTICS__)
+                        if(unlikely(external)) __atomic_fetch_add(&cltr->stats->ready.push.extrn.success, 1, __ATOMIC_RELAXED);
+                        else __tls_stats()->ready.push.local.success++;
+                #endif
+
+                __cfadbg_print_safe(ready_queue, "Kernel : Pushed %p on cluster %p (idx: %u, mask %llu, first %d)\n", thrd, cltr, i, used.mask[0], lane_first);
+
+        }
+
+        // Pop from the ready queue from a given cluster
+        __attribute__((hot)) thread$ * pop_fast(struct cluster * cltr) with (cltr->ready_queue) {
+                /* paranoid */ verify( lanes.count > 0 );
+                /* paranoid */ verify( kernelTLS().this_processor );
+
+                processor * const proc = kernelTLS().this_processor;
+                const int cpu = __kernel_getcpu();
+                /* paranoid */ verify(cpu >= 0);
+                /* paranoid */ verify(cpu < cpu_info.hthrd_count);
+                /* paranoid */ verify(cpu * READYQ_SHARD_FACTOR < lanes.count);
+
+                const cpu_map_entry_t & map = cpu_info.llc_map[cpu];
+                /* paranoid */ verify(map.start * READYQ_SHARD_FACTOR < lanes.count);
+                /* paranoid */ verify(map.self * READYQ_SHARD_FACTOR < lanes.count);
+                /* paranoid */ verifyf((map.start + map.count) * READYQ_SHARD_FACTOR <= lanes.count, "have %zu lanes but map can go up to %u", lanes.count, (map.start + map.count) * READYQ_SHARD_FACTOR);
+
+                const int start = map.self * READYQ_SHARD_FACTOR;
+                const unsigned long long ctsc = rdtscl();
+
+                // Did we already have a help target
+                if(proc->rdq.target == MAX) {
+                        unsigned long long max = 0;
+                        for(i; READYQ_SHARD_FACTOR) {
+                                unsigned long long tsc = moving_average(ctsc, ts(lanes.data[start + i]), lanes.tscs[start + i].ma);
+                                if(tsc > max) max = tsc;
+                        }
+                        //  proc->rdq.cutoff = (max + 2 * max) / 2;
+                        /* paranoid */ verify(lanes.count < 65536); // The following code assumes max 65536 cores.
+                        /* paranoid */ verify(map.count < 65536); // The following code assumes max 65536 cores.
+
+                        if(0 == (__tls_rand() % 100)) {
+                                proc->rdq.target = __tls_rand() % lanes.count;
+                        } else {
+                                unsigned cpu_chaos = map.start + (__tls_rand() % map.count);
+                                proc->rdq.target = (cpu_chaos * READYQ_SHARD_FACTOR) + (__tls_rand() % READYQ_SHARD_FACTOR);
+                                /* paranoid */ verify(proc->rdq.target >= (map.start * READYQ_SHARD_FACTOR));
+                                /* paranoid */ verify(proc->rdq.target <  ((map.start + map.count) * READYQ_SHARD_FACTOR));
+                        }
+
+                        /* paranoid */ verify(proc->rdq.target != MAX);
+                }
+                else {
+                        unsigned long long max = 0;
+                        for(i; READYQ_SHARD_FACTOR) {
+                                unsigned long long tsc = moving_average(ctsc, ts(lanes.data[start + i]), lanes.tscs[start + i].ma);
+                                if(tsc > max) max = tsc;
+                        }
+                        const unsigned long long cutoff = (max + 2 * max) / 2;
+                        {
+                                unsigned target = proc->rdq.target;
+                                proc->rdq.target = MAX;
+                                lanes.help[target / READYQ_SHARD_FACTOR].tri++;
+                                if(moving_average(ctsc, lanes.tscs[target].tv, lanes.tscs[target].ma) > cutoff) {
+                                        thread$ * t = try_pop(cltr, target __STATS(, __tls_stats()->ready.pop.help));
+                                        proc->rdq.last = target;
+                                        if(t) return t;
+                                }
+                                proc->rdq.target = MAX;
+                        }
+
+                        unsigned last = proc->rdq.last;
+                        if(last != MAX && moving_average(ctsc, lanes.tscs[last].tv, lanes.tscs[last].ma) > cutoff) {
+                                thread$ * t = try_pop(cltr, last __STATS(, __tls_stats()->ready.pop.help));
+                                if(t) return t;
+                        }
+                        else {
+                                proc->rdq.last = MAX;
+                        }
+                }
+
+                for(READYQ_SHARD_FACTOR) {
+                        unsigned i = start + (proc->rdq.itr++ % READYQ_SHARD_FACTOR);
+                        if(thread$ * t = try_pop(cltr, i __STATS(, __tls_stats()->ready.pop.local))) return t;
+                }
+
+                // All lanes where empty return 0p
+                return 0p;
+        }
+
+        __attribute__((hot)) struct thread$ * pop_slow(struct cluster * cltr) with (cltr->ready_queue) {
+                processor * const proc = kernelTLS().this_processor;
+                unsigned last = proc->rdq.last;
+                if(last != MAX) {
+                        struct thread$ * t = try_pop(cltr, last __STATS(, __tls_stats()->ready.pop.steal));
+                        if(t) return t;
+                        proc->rdq.last = MAX;
+                }
+
+                unsigned i = __tls_rand() % lanes.count;
+                return try_pop(cltr, i __STATS(, __tls_stats()->ready.pop.steal));
+        }
+        __attribute__((hot)) struct thread$ * pop_search(struct cluster * cltr) {
+                return search(cltr);
+        }
+#endif
+#if defined(USE_RELAXED_FIFO)
+        //-----------------------------------------------------------------------
+        // get index from random number with or without bias towards queues
+        static inline [unsigned, bool] idx_from_r(unsigned r, unsigned preferred) {
+                unsigned i;
+                bool local;
+                unsigned rlow  = r % BIAS;
+                unsigned rhigh = r / BIAS;
+                if((0 != rlow) && preferred >= 0) {
+                        // (BIAS - 1) out of BIAS chances
+                        // Use perferred queues
+                        i = preferred + (rhigh % READYQ_SHARD_FACTOR);
+                        local = true;
+                }
+                else {
+                        // 1 out of BIAS chances
+                        // Use all queues
+                        i = rhigh;
+                        local = false;
+                }
+                return [i, local];
+        }
+
+        __attribute__((hot)) void push(struct cluster * cltr, struct thread$ * thrd, unpark_hint hint) with (cltr->ready_queue) {
+                __cfadbg_print_safe(ready_queue, "Kernel : Pushing %p on cluster %p\n", thrd, cltr);
+
+                const bool external = (hint != UNPARK_LOCAL) || (!kernelTLS().this_processor) || (cltr != kernelTLS().this_processor->cltr);
+                /* paranoid */ verify(external || kernelTLS().this_processor->rdq.id < lanes.count );
+
+                bool local;
+                int preferred = external ? -1 : kernelTLS().this_processor->rdq.id;
+
+                // Try to pick a lane and lock it
+                unsigned i;
+                do {
+                        // Pick the index of a lane
+                        unsigned r = __tls_rand_fwd();
+                        [i, local] = idx_from_r(r, preferred);
+
+                        i %= __atomic_load_n( &lanes.count, __ATOMIC_RELAXED );
+
+                        #if !defined(__CFA_NO_STATISTICS__)
+                                if(unlikely(external)) __atomic_fetch_add(&cltr->stats->ready.push.extrn.attempt, 1, __ATOMIC_RELAXED);
+                                else if(local) __tls_stats()->ready.push.local.attempt++;
+                                else __tls_stats()->ready.push.share.attempt++;
+                        #endif
+
+                        // If we can't lock it retry
+                } while( !__atomic_try_acquire( &lanes.data[i].lock ) );
+
+                // Actually push it
+                push(lanes.data[i], thrd);
+
+                // Unlock and return
+                __atomic_unlock( &lanes.data[i].lock );
+
+                // Mark the current index in the tls rng instance as having an item
+                __tls_rand_advance_bck();
+
+                __cfadbg_print_safe(ready_queue, "Kernel : Pushed %p on cluster %p (idx: %u, mask %llu, first %d)\n", thrd, cltr, i, used.mask[0], lane_first);
+
+                // Update statistics
+                #if !defined(__CFA_NO_STATISTICS__)
+                        if(unlikely(external)) __atomic_fetch_add(&cltr->stats->ready.push.extrn.success, 1, __ATOMIC_RELAXED);
+                        else if(local) __tls_stats()->ready.push.local.success++;
+                        else __tls_stats()->ready.push.share.success++;
+                #endif
+        }
+
+        // Pop from the ready queue from a given cluster
+        __attribute__((hot)) thread$ * pop_fast(struct cluster * cltr) with (cltr->ready_queue) {
+                /* paranoid */ verify( lanes.count > 0 );
+                /* paranoid */ verify( kernelTLS().this_processor );
+                /* paranoid */ verify( kernelTLS().this_processor->rdq.id < lanes.count );
+
+                unsigned count = __atomic_load_n( &lanes.count, __ATOMIC_RELAXED );
+                int preferred = kernelTLS().this_processor->rdq.id;
+
+
+                // As long as the list is not empty, try finding a lane that isn't empty and pop from it
+                for(25) {
+                        // Pick two lists at random
+                        unsigned ri = __tls_rand_bck();
+                        unsigned rj = __tls_rand_bck();
+
+                        unsigned i, j;
+                        __attribute__((unused)) bool locali, localj;
+                        [i, locali] = idx_from_r(ri, preferred);
+                        [j, localj] = idx_from_r(rj, preferred);
+
+                        i %= count;
+                        j %= count;
+
+                        // try popping from the 2 picked lists
+                        struct thread$ * thrd = try_pop(cltr, i, j __STATS(, *(locali || localj ? &__tls_stats()->ready.pop.local : &__tls_stats()->ready.pop.help)));
+                        if(thrd) {
+                                return thrd;
+                        }
+                }
+
+                // All lanes where empty return 0p
+                return 0p;
+        }
+
+        __attribute__((hot)) struct thread$ * pop_slow(struct cluster * cltr) { return pop_fast(cltr); }
+        __attribute__((hot)) struct thread$ * pop_search(struct cluster * cltr) {
+                return search(cltr);
+        }
+#endif
+#if defined(USE_WORK_STEALING)
+        __attribute__((hot)) void push(struct cluster * cltr, struct thread$ * thrd, unpark_hint hint) with (cltr->ready_queue) {
+                __cfadbg_print_safe(ready_queue, "Kernel : Pushing %p on cluster %p\n", thrd, cltr);
+
+                // #define USE_PREFERRED
+                #if !defined(USE_PREFERRED)
+                const bool external = (hint != UNPARK_LOCAL) || (!kernelTLS().this_processor) || (cltr != kernelTLS().this_processor->cltr);
+                /* paranoid */ verify(external || kernelTLS().this_processor->rdq.id < lanes.count );
+                #else
+                        unsigned preferred = thrd->preferred;
+                        const bool external = (hint != UNPARK_LOCAL) || (!kernelTLS().this_processor) || preferred == MAX || thrd->curr_cluster != cltr;
+                        /* paranoid */ verifyf(external || preferred < lanes.count, "Invalid preferred queue %u for %u lanes", preferred, lanes.count );
+
+                        unsigned r = preferred % READYQ_SHARD_FACTOR;
+                        const unsigned start = preferred - r;
+                #endif
+
+                // Try to pick a lane and lock it
+                unsigned i;
+                do {
+                        #if !defined(__CFA_NO_STATISTICS__)
+                                if(unlikely(external)) __atomic_fetch_add(&cltr->stats->ready.push.extrn.attempt, 1, __ATOMIC_RELAXED);
+                                else __tls_stats()->ready.push.local.attempt++;
+                        #endif
+
+                        if(unlikely(external)) {
+                                i = __tls_rand() % lanes.count;
+                        }
+                        else {
+                                #if !defined(USE_PREFERRED)
+                                        processor * proc = kernelTLS().this_processor;
+                                        unsigned r = proc->rdq.its++;
+                                        i =  proc->rdq.id + (r % READYQ_SHARD_FACTOR);
+                                #else
+                                        i = start + (r++ % READYQ_SHARD_FACTOR);
+                                #endif
+                        }
+                        // If we can't lock it retry
+                } while( !__atomic_try_acquire( &lanes.data[i].lock ) );
+
+                // Actually push it
+                push(lanes.data[i], thrd);
+
+                // Unlock and return
+                __atomic_unlock( &lanes.data[i].lock );
+
+                #if !defined(__CFA_NO_STATISTICS__)
+                        if(unlikely(external)) __atomic_fetch_add(&cltr->stats->ready.push.extrn.success, 1, __ATOMIC_RELAXED);
+                        else __tls_stats()->ready.push.local.success++;
+                #endif
+
+                __cfadbg_print_safe(ready_queue, "Kernel : Pushed %p on cluster %p (idx: %u, mask %llu, first %d)\n", thrd, cltr, i, used.mask[0], lane_first);
+        }
+
+        // Pop from the ready queue from a given cluster
+        __attribute__((hot)) thread$ * pop_fast(struct cluster * cltr) with (cltr->ready_queue) {
+                /* paranoid */ verify( lanes.count > 0 );
+                /* paranoid */ verify( kernelTLS().this_processor );
+                /* paranoid */ verify( kernelTLS().this_processor->rdq.id < lanes.count );
+
+                processor * proc = kernelTLS().this_processor;
+
+                if(proc->rdq.target == MAX) {
+                        unsigned long long min = ts(lanes.data[proc->rdq.id]);
+                        for(int i = 0; i < READYQ_SHARD_FACTOR; i++) {
+                                unsigned long long tsc = ts(lanes.data[proc->rdq.id + i]);
+                                if(tsc < min) min = tsc;
+                        }
+                        proc->rdq.cutoff = min;
+                        proc->rdq.target = __tls_rand() % lanes.count;
+                }
+                else {
+                        unsigned target = proc->rdq.target;
+                        proc->rdq.target = MAX;
+                        const unsigned long long bias = 0; //2_500_000_000;
+                        const unsigned long long cutoff = proc->rdq.cutoff > bias ? proc->rdq.cutoff - bias : proc->rdq.cutoff;
+                        if(lanes.tscs[target].tv < cutoff && ts(lanes.data[target]) < cutoff) {
                                 thread$ * t = try_pop(cltr, target __STATS(, __tls_stats()->ready.pop.help));
                                 if(t) return t;
                         }
                 }
-                proc->rdq.target = MAX;
-        }
-
-        for(__shard_factor.readyq) {
-                unsigned i = this + (proc->rdq.itr++ % __shard_factor.readyq);
-                if(thread$ * t = try_pop(cltr, i __STATS(, __tls_stats()->ready.pop.local))) return t;
-        }
-
-        // All lanes where empty return 0p
-        return 0p;
-
-}
-__attribute__((hot)) struct thread$ * pop_slow(struct cluster * cltr) {
-        unsigned i = __tls_rand() % (cltr->sched.readyQ.count);
-        return try_pop(cltr, i __STATS(, __tls_stats()->ready.pop.steal));
-}
-__attribute__((hot)) struct thread$ * pop_search(struct cluster * cltr) {
-        return search(cltr);
-}
+
+                for(READYQ_SHARD_FACTOR) {
+                        unsigned i = proc->rdq.id + (proc->rdq.itr++ % READYQ_SHARD_FACTOR);
+                        if(thread$ * t = try_pop(cltr, i __STATS(, __tls_stats()->ready.pop.local))) return t;
+                }
+                return 0p;
+        }
+
+        __attribute__((hot)) struct thread$ * pop_slow(struct cluster * cltr) with (cltr->ready_queue) {
+                unsigned i = __tls_rand() % lanes.count;
+                return try_pop(cltr, i __STATS(, __tls_stats()->ready.pop.steal));
+        }
+
+        __attribute__((hot)) struct thread$ * pop_search(struct cluster * cltr) with (cltr->ready_queue) {
+                return search(cltr);
+        }
+#endif
 
 //=======================================================================
@@ -175 +820 @@
 //-----------------------------------------------------------------------
 // try to pop from a lane given by index w
-static inline struct thread$ * try_pop(struct cluster * cltr, unsigned w __STATS(, __stats_readyQ_pop_t & stats)) with (cltr->sched) {
-        /* paranoid */ verify( w < readyQ.count );
+static inline struct thread$ * try_pop(struct cluster * cltr, unsigned w __STATS(, __stats_readyQ_pop_t & stats)) with (cltr->ready_queue) {
+        /* paranoid */ verify( w < lanes.count );
         __STATS( stats.attempt++; )
 
         // Get relevant elements locally
-        __intrusive_lane_t & lane = readyQ.data[w];
+        __intrusive_lane_t & lane = lanes.data[w];
 
         // If list looks empty retry
@@ -200 +845 @@
         // Actually pop the list
         struct thread$ * thrd;
-        unsigned long long ts_prev = ts(lane);
-        unsigned long long ts_next;
-        [thrd, ts_next] = pop(lane);
+        #if defined(USE_AWARE_STEALING) || defined(USE_WORK_STEALING) || defined(USE_CPU_WORK_STEALING)
+                unsigned long long tsc_before = ts(lane);
+        #endif
+        unsigned long long tsv;
+        [thrd, tsv] = pop(lane);
 
         /* paranoid */ verify(thrd);
-        /* paranoid */ verify(ts_next);
+        /* paranoid */ verify(tsv);
         /* paranoid */ verify(lane.lock);
 
@@ -214 +861 @@
         __STATS( stats.success++; )
 
-        touch_tsc(readyQ.tscs, w, ts_prev, ts_next);
-
-        thrd->preferred = w / __shard_factor.readyq;
+        #if defined(USE_AWARE_STEALING) || defined(USE_WORK_STEALING) || defined(USE_CPU_WORK_STEALING)
+                if (tsv != MAX) {
+                        unsigned long long now = rdtscl();
+                        unsigned long long pma = __atomic_load_n(&lanes.tscs[w].ma, __ATOMIC_RELAXED);
+                        __atomic_store_n(&lanes.tscs[w].tv, tsv, __ATOMIC_RELAXED);
+                        __atomic_store_n(&lanes.tscs[w].ma, moving_average(now, tsc_before, pma), __ATOMIC_RELAXED);
+                }
+        #endif
+
+        #if defined(USE_AWARE_STEALING) || defined(USE_CPU_WORK_STEALING)
+                thrd->preferred = w / READYQ_SHARD_FACTOR;
+        #else
+                thrd->preferred = w;
+        #endif
 
         // return the popped thread
@@ -225 +883 @@
 // try to pop from any lanes making sure you don't miss any threads push
 // before the start of the function
-static inline struct thread$ * search(struct cluster * cltr) {
-        const size_t lanes_count = cltr->sched.readyQ.count;
-        /* paranoid */ verify( lanes_count > 0 );
-        unsigned count = __atomic_load_n( &lanes_count, __ATOMIC_RELAXED );
+static inline struct thread$ * search(struct cluster * cltr) with (cltr->ready_queue) {
+        /* paranoid */ verify( lanes.count > 0 );
+        unsigned count = __atomic_load_n( &lanes.count, __ATOMIC_RELAXED );
         unsigned offset = __tls_rand();
         for(i; count) {
@@ -245 +902 @@
 // get preferred ready for new thread
 unsigned ready_queue_new_preferred() {
-        unsigned pref = MAX;
+        unsigned pref = 0;
         if(struct thread$ * thrd = publicTLS_get( this_thread )) {
                 pref = thrd->preferred;
         }
+        else {
+                #if defined(USE_CPU_WORK_STEALING)
+                        pref = __kernel_getcpu();
+                #endif
+        }
+
+        #if defined(USE_CPU_WORK_STEALING)
+                /* paranoid */ verify(pref >= 0);
+                /* paranoid */ verify(pref < cpu_info.hthrd_count);
+        #endif
 
         return pref;
+}
+
+//-----------------------------------------------------------------------
+// Check that all the intrusive queues in the data structure are still consistent
+static void check( __ready_queue_t & q ) with (q) {
+        #if defined(__CFA_WITH_VERIFY__)
+                {
+                        for( idx ; lanes.count ) {
+                                __intrusive_lane_t & sl = lanes.data[idx];
+                                assert(!lanes.data[idx].lock);
+
+                                        if(is_empty(sl)) {
+                                                assert( sl.anchor.next == 0p );
+                                                assert( sl.anchor.ts   == -1llu );
+                                                assert( mock_head(sl)  == sl.prev );
+                                        } else {
+                                                assert( sl.anchor.next != 0p );
+                                                assert( sl.anchor.ts   != -1llu );
+                                                assert( mock_head(sl)  != sl.prev );
+                                        }
+                        }
+                }
+        #endif
 }
 
 //-----------------------------------------------------------------------
 // Given 2 indexes, pick the list with the oldest push an try to pop from it
-static inline struct thread$ * try_pop(struct cluster * cltr, unsigned i, unsigned j __STATS(, __stats_readyQ_pop_t & stats)) with (cltr->sched) {
+static inline struct thread$ * try_pop(struct cluster * cltr, unsigned i, unsigned j __STATS(, __stats_readyQ_pop_t & stats)) with (cltr->ready_queue) {
         // Pick the bet list
         int w = i;
-        if( __builtin_expect(!is_empty(readyQ.data[j]), true) ) {
-                w = (ts(readyQ.data[i]) < ts(readyQ.data[j])) ? i : j;
+        if( __builtin_expect(!is_empty(lanes.data[j]), true) ) {
+                w = (ts(lanes.data[i]) < ts(lanes.data[j])) ? i : j;
         }
 
         return try_pop(cltr, w __STATS(, stats));
 }
+
+// Call this function of the intrusive list was moved using memcpy
+// fixes the list so that the pointers back to anchors aren't left dangling
+static inline void fix(__intrusive_lane_t & ll) {
+                        if(is_empty(ll)) {
+                                verify(ll.anchor.next == 0p);
+                                ll.prev = mock_head(ll);
+                        }
+}
+
+static void assign_list(unsigned & value, dlist(processor) & list, unsigned count) {
+        processor * it = &list`first;
+        for(unsigned i = 0; i < count; i++) {
+                /* paranoid */ verifyf( it, "Unexpected null iterator, at index %u of %u\n", i, count);
+                it->rdq.id = value;
+                it->rdq.target = MAX;
+                value += READYQ_SHARD_FACTOR;
+                it = &(*it)`next;
+        }
+}
+
+static void reassign_cltr_id(struct cluster * cltr) {
+        unsigned preferred = 0;
+        assign_list(preferred, cltr->procs.actives, cltr->procs.total - cltr->procs.idle);
+        assign_list(preferred, cltr->procs.idles  , cltr->procs.idle );
+}
+
+static void fix_times( struct cluster * cltr ) with( cltr->ready_queue ) {
+        #if defined(USE_AWARE_STEALING) || defined(USE_WORK_STEALING)
+                lanes.tscs = alloc(lanes.count, lanes.tscs`realloc);
+                for(i; lanes.count) {
+                        lanes.tscs[i].tv = rdtscl();
+                        lanes.tscs[i].ma = 0;
+                }
+        #endif
+}
+
+#if defined(USE_CPU_WORK_STEALING)
+        // ready_queue size is fixed in this case
+        void ready_queue_grow(struct cluster * cltr) {}
+        void ready_queue_shrink(struct cluster * cltr) {}
+#else
+        // Grow the ready queue
+        void ready_queue_grow(struct cluster * cltr) {
+                size_t ncount;
+                int target = cltr->procs.total;
+
+                /* paranoid */ verify( ready_mutate_islocked() );
+                __cfadbg_print_safe(ready_queue, "Kernel : Growing ready queue\n");
+
+                // Make sure that everything is consistent
+                /* paranoid */ check( cltr->ready_queue );
+
+                // grow the ready queue
+                with( cltr->ready_queue ) {
+                        // Find new count
+                        // Make sure we always have atleast 1 list
+                        if(target >= 2) {
+                                ncount = target * READYQ_SHARD_FACTOR;
+                        } else {
+                                ncount = SEQUENTIAL_SHARD;
+                        }
+
+                        // Allocate new array (uses realloc and memcpies the data)
+                        lanes.data = alloc( ncount, lanes.data`realloc );
+
+                        // Fix the moved data
+                        for( idx; (size_t)lanes.count ) {
+                                fix(lanes.data[idx]);
+                        }
+
+                        // Construct new data
+                        for( idx; (size_t)lanes.count ~ ncount) {
+                                (lanes.data[idx]){};
+                        }
+
+                        // Update original
+                        lanes.count = ncount;
+
+                        lanes.caches = alloc( target, lanes.caches`realloc );
+                }
+
+                fix_times(cltr);
+
+                reassign_cltr_id(cltr);
+
+                // Make sure that everything is consistent
+                /* paranoid */ check( cltr->ready_queue );
+
+                __cfadbg_print_safe(ready_queue, "Kernel : Growing ready queue done\n");
+
+                /* paranoid */ verify( ready_mutate_islocked() );
+        }
+
+        // Shrink the ready queue
+        void ready_queue_shrink(struct cluster * cltr) {
+                /* paranoid */ verify( ready_mutate_islocked() );
+                __cfadbg_print_safe(ready_queue, "Kernel : Shrinking ready queue\n");
+
+                // Make sure that everything is consistent
+                /* paranoid */ check( cltr->ready_queue );
+
+                int target = cltr->procs.total;
+
+                with( cltr->ready_queue ) {
+                        // Remember old count
+                        size_t ocount = lanes.count;
+
+                        // Find new count
+                        // Make sure we always have atleast 1 list
+                        lanes.count = target >= 2 ? target * READYQ_SHARD_FACTOR: SEQUENTIAL_SHARD;
+                        /* paranoid */ verify( ocount >= lanes.count );
+                        /* paranoid */ verify( lanes.count == target * READYQ_SHARD_FACTOR || target < 2 );
+
+                        // for printing count the number of displaced threads
+                        #if defined(__CFA_DEBUG_PRINT__) || defined(__CFA_DEBUG_PRINT_READY_QUEUE__)
+                                __attribute__((unused)) size_t displaced = 0;
+                        #endif
+
+                        // redistribute old data
+                        for( idx; (size_t)lanes.count ~ ocount) {
+                                // Lock is not strictly needed but makes checking invariants much easier
+                                __attribute__((unused)) bool locked = __atomic_try_acquire(&lanes.data[idx].lock);
+                                verify(locked);
+
+                                // As long as we can pop from this lane to push the threads somewhere else in the queue
+                                while(!is_empty(lanes.data[idx])) {
+                                        struct thread$ * thrd;
+                                        unsigned long long _;
+                                        [thrd, _] = pop(lanes.data[idx]);
+
+                                        push(cltr, thrd, true);
+
+                                        // for printing count the number of displaced threads
+                                        #if defined(__CFA_DEBUG_PRINT__) || defined(__CFA_DEBUG_PRINT_READY_QUEUE__)
+                                                displaced++;
+                                        #endif
+                                }
+
+                                // Unlock the lane
+                                __atomic_unlock(&lanes.data[idx].lock);
+
+                                // TODO print the queue statistics here
+
+                                ^(lanes.data[idx]){};
+                        }
+
+                        __cfadbg_print_safe(ready_queue, "Kernel : Shrinking ready queue displaced %zu threads\n", displaced);
+
+                        // Allocate new array (uses realloc and memcpies the data)
+                        lanes.data = alloc( lanes.count, lanes.data`realloc );
+
+                        // Fix the moved data
+                        for( idx; (size_t)lanes.count ) {
+                                fix(lanes.data[idx]);
+                        }
+
+                        lanes.caches = alloc( target, lanes.caches`realloc );
+                }
+
+                fix_times(cltr);
+
+
+                reassign_cltr_id(cltr);
+
+                // Make sure that everything is consistent
+                /* paranoid */ check( cltr->ready_queue );
+
+                __cfadbg_print_safe(ready_queue, "Kernel : Shrinking ready queue done\n");
+                /* paranoid */ verify( ready_mutate_islocked() );
+        }
+#endif
+
+#if !defined(__CFA_NO_STATISTICS__)
+        unsigned cnt(const __ready_queue_t & this, unsigned idx) {
+                /* paranoid */ verify(this.lanes.count > idx);
+                return this.lanes.data[idx].cnt;
+        }
+#endif
+
+
+#if   defined(CFA_HAVE_LINUX_LIBRSEQ)
+        // No definition needed
+#elif defined(CFA_HAVE_LINUX_RSEQ_H)
+
+        #if defined( __x86_64 ) || defined( __i386 )
+                #define RSEQ_SIG        0x53053053
+        #elif defined( __ARM_ARCH )
+                #ifdef __ARMEB__
+                #define RSEQ_SIG    0xf3def5e7      /* udf    #24035    ; 0x5de3 (ARMv6+) */
+                #else
+                #define RSEQ_SIG    0xe7f5def3      /* udf    #24035    ; 0x5de3 */
+                #endif
+        #endif
+
+        extern void __disable_interrupts_hard();
+        extern void __enable_interrupts_hard();
+
+        static void __kernel_raw_rseq_register  (void) {
+                /* paranoid */ verify( __cfaabi_rseq.cpu_id == RSEQ_CPU_ID_UNINITIALIZED );
+
+                // int ret = syscall(__NR_rseq, &__cfaabi_rseq, sizeof(struct rseq), 0, (sigset_t *)0p, _NSIG / 8);
+                int ret = syscall(__NR_rseq, &__cfaabi_rseq, sizeof(struct rseq), 0, RSEQ_SIG);
+                if(ret != 0) {
+                        int e = errno;
+                        switch(e) {
+                        case EINVAL: abort("KERNEL ERROR: rseq register invalid argument");
+                        case ENOSYS: abort("KERNEL ERROR: rseq register no supported");
+                        case EFAULT: abort("KERNEL ERROR: rseq register with invalid argument");
+                        case EBUSY : abort("KERNEL ERROR: rseq register already registered");
+                        case EPERM : abort("KERNEL ERROR: rseq register sig  argument  on unregistration does not match the signature received on registration");
+                        default: abort("KERNEL ERROR: rseq register unexpected return %d", e);
+                        }
+                }
+        }
+
+        static void __kernel_raw_rseq_unregister(void) {
+                /* paranoid */ verify( __cfaabi_rseq.cpu_id >= 0 );
+
+                // int ret = syscall(__NR_rseq, &__cfaabi_rseq, sizeof(struct rseq), RSEQ_FLAG_UNREGISTER, (sigset_t *)0p, _NSIG / 8);
+                int ret = syscall(__NR_rseq, &__cfaabi_rseq, sizeof(struct rseq), RSEQ_FLAG_UNREGISTER, RSEQ_SIG);
+                if(ret != 0) {
+                        int e = errno;
+                        switch(e) {
+                        case EINVAL: abort("KERNEL ERROR: rseq unregister invalid argument");
+                        case ENOSYS: abort("KERNEL ERROR: rseq unregister no supported");
+                        case EFAULT: abort("KERNEL ERROR: rseq unregister with invalid argument");
+                        case EBUSY : abort("KERNEL ERROR: rseq unregister already registered");
+                        case EPERM : abort("KERNEL ERROR: rseq unregister sig  argument  on unregistration does not match the signature received on registration");
+                        default: abort("KERNEL ERROR: rseq unregisteunexpected return %d", e);
+                        }
+                }
+        }
+#else
+        // No definition needed
+#endif