Changeset a757ba1 for libcfa/src/concurrency

Timestamp:

Nov 10, 2022, 12:17:20 PM (2 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, ast-experimental, master

Children:

639e4fc

Parents:

6a4ef0c

Message:

Removed wait-with-io_uring feature which was slow, broken and ifdefed out.

Location:

libcfa/src/concurrency

Files:

• io.cfa (modified) (1 diff)
• io/setup.cfa (modified) (2 diffs)
• kernel.cfa (modified) (5 diffs)
• kernel.hfa (modified) (2 diffs)
• kernel/private.hfa (modified) (1 diff)
• kernel/startup.cfa (modified) (3 diffs)

libcfa/src/concurrency/io.cfa

@@ -639 +639 @@
                 }
         }
-
-        #if defined(CFA_WITH_IO_URING_IDLE)
-                bool __kernel_read(struct processor * proc, io_future_t & future, iovec & iov, int fd) {
-                        io_context$ * ctx = proc->io.ctx;
-                        /* paranoid */ verify( ! __preemption_enabled() );
-                        /* paranoid */ verify( proc == __cfaabi_tls.this_processor );
-                        /* paranoid */ verify( ctx );
-
-                        __u32 idx;
-                        struct io_uring_sqe * sqe;
-
-                        // We can proceed to the fast path
-                        if( !__alloc(ctx, &idx, 1) ) {
-                                /* paranoid */ verify( false ); // for now check if this happens, next time just abort the sleep.
-                                return false;
-                        }
-
-                        // Allocation was successful
-                        __fill( &sqe, 1, &idx, ctx );
-
-                        sqe->user_data = (uintptr_t)&future;
-                        sqe->flags = 0;
-                        sqe->fd = fd;
-                        sqe->off = 0;
-                        sqe->ioprio = 0;
-                        sqe->fsync_flags = 0;
-                        sqe->__pad2[0] = 0;
-                        sqe->__pad2[1] = 0;
-                        sqe->__pad2[2] = 0;
-
-                        #if defined(CFA_HAVE_IORING_OP_READ)
-                                sqe->opcode = IORING_OP_READ;
-                                sqe->addr = (uint64_t)iov.iov_base;
-                                sqe->len = iov.iov_len;
-                        #elif defined(CFA_HAVE_READV) && defined(CFA_HAVE_IORING_OP_READV)
-                                sqe->opcode = IORING_OP_READV;
-                                sqe->addr = (uintptr_t)&iov;
-                                sqe->len = 1;
-                        #else
-                                #error CFA_WITH_IO_URING_IDLE but none of CFA_HAVE_READV, CFA_HAVE_IORING_OP_READV or CFA_HAVE_IORING_OP_READ defined
-                        #endif
-
-                        asm volatile("": : :"memory");
-
-                        /* paranoid */ verify( sqe->user_data == (uintptr_t)&future );
-                        __submit_only( ctx, &idx, 1 );
-
-                        /* paranoid */ verify( proc == __cfaabi_tls.this_processor );
-                        /* paranoid */ verify( ! __preemption_enabled() );
-
-                        return true;
-                }
-
-                void __cfa_io_idle( struct processor * proc ) {
-                        iovec iov;
-                        __atomic_acquire( &proc->io.ctx->cq.lock );
-
-                        __attribute__((used)) volatile bool was_reset = false;
-
-                        with( proc->idle_wctx) {
-
-                                // Do we already have a pending read
-                                if(available(*ftr)) {
-                                        // There is no pending read, we need to add one
-                                        reset(*ftr);
-
-                                        iov.iov_base = rdbuf;
-                                        iov.iov_len  = sizeof(eventfd_t);
-                                        __kernel_read(proc, *ftr, iov, evfd );
-                                        ftr->result = 0xDEADDEAD;
-                                        *((eventfd_t *)rdbuf) = 0xDEADDEADDEADDEAD;
-                                        was_reset = true;
-                                }
-                        }
-
-                        if( !__atomic_load_n( &proc->do_terminate, __ATOMIC_SEQ_CST ) ) {
-                                __ioarbiter_flush( *proc->io.ctx );
-                                proc->idle_wctx.sleep_time = rdtscl();
-                                ioring_syscsll( *proc->io.ctx, 1, IORING_ENTER_GETEVENTS);
-                        }
-
-                        ready_schedule_lock();
-                        __cfa_do_drain( proc->io.ctx, proc->cltr );
-                        ready_schedule_unlock();
-
-                        asm volatile ("" :: "m" (was_reset));
-                }
-        #endif
 #endif

libcfa/src/concurrency/io/setup.cfa

@@ -34 +34 @@
         bool __cfa_io_flush( processor * proc ) { return false; }
         bool __cfa_io_drain( processor * proc ) __attribute__((nonnull (1))) { return false; }
-        void __cfa_io_idle ( processor * ) __attribute__((nonnull (1))) {}
         void __cfa_io_stop ( processor * proc ) {}
 
@@ -317 +316 @@
         }
 
-//=============================================================================================
-// I/O Context Sleep
-//=============================================================================================
-        // static inline void __epoll_ctl(io_context$ & ctx, int op, const char * error) {
-        //      struct epoll_event ev;
-        //      ev.events = EPOLLIN | EPOLLONESHOT;
-        //      ev.data.u64 = (__u64)&ctx;
-        //      int ret = epoll_ctl(iopoll.epollfd, op, ctx.efd, &ev);
-        //      if (ret < 0) {
-        //              abort( "KERNEL ERROR: EPOLL %s - (%d) %s\n", error, (int)errno, strerror(errno) );
-        //      }
-        // }
-
-        // static void __epoll_register(io_context$ & ctx) {
-        //      __epoll_ctl(ctx, EPOLL_CTL_ADD, "ADD");
-        // }
-
-        // static void __epoll_unregister(io_context$ & ctx) {
-        //      // Read the current epoch so we know when to stop
-        //      size_t curr = __atomic_load_n(&iopoll.epoch, __ATOMIC_SEQ_CST);
-
-        //      // Remove the fd from the iopoller
-        //      __epoll_ctl(ctx, EPOLL_CTL_DEL, "REMOVE");
-
-        //      // Notify the io poller thread of the shutdown
-        //      iopoll.run = false;
-        //      sigval val = { 1 };
-        //      __cfaabi_pthread_sigqueue( iopoll.thrd, SIGUSR1, val );
-
-        //      // Make sure all this is done
-        //      __atomic_thread_fence(__ATOMIC_SEQ_CST);
-
-        //      // Wait for the next epoch
-        //      while(curr == iopoll.epoch && !iopoll.stopped) Pause();
-        // }
-
-        // void __ioctx_prepare_block(io_context$ & ctx) {
-        //      __cfadbg_print_safe(io_core, "Kernel I/O - epoll : Re-arming io poller %d (%p)\n", ctx.fd, &ctx);
-        //      __epoll_ctl(ctx, EPOLL_CTL_MOD, "REARM");
-        // }
-
 
 //=============================================================================================

libcfa/src/concurrency/kernel.cfa

@@ -138 +138 @@
 extern bool __cfa_io_drain( processor * proc ) __attribute__((nonnull (1)));
 extern bool __cfa_io_flush( processor * ) __attribute__((nonnull (1)));
-extern void __cfa_io_idle( processor * ) __attribute__((nonnull (1)));
-
-#if defined(CFA_WITH_IO_URING_IDLE)
-        extern bool __kernel_read(processor * proc, io_future_t & future, iovec &, int fd);
-#endif
+
 
 extern void __disable_interrupts_hard();
@@ -161 +157 @@
         processor * this = runner.proc;
         verify(this);
-
-        /* paranoid */ verify( this->idle_wctx.ftr   != 0p );
-        /* paranoid */ verify( this->idle_wctx.rdbuf != 0p );
-
-        // used for idle sleep when io_uring is present
-        // mark it as already fulfilled so we know if there is a pending request or not
-        this->idle_wctx.ftr->self.ptr = 1p;
 
         __cfadbg_print_safe(runtime_core, "Kernel : core %p starting\n", this);
@@ -730 +719 @@
 
 
-        #if !defined(CFA_WITH_IO_URING_IDLE)
-                #if !defined(__CFA_NO_STATISTICS__)
-                        if(this->print_halts) {
-                                __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl());
+        #if !defined(__CFA_NO_STATISTICS__)
+                if(this->print_halts) {
+                        __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 0\n", this->unique_id, rdtscl());
+                }
+        #endif
+
+        __cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle_fd);
+
+        {
+                eventfd_t val;
+                ssize_t ret = read( this->idle_wctx.evfd, &val, sizeof(val) );
+                if(ret < 0) {
+                        switch((int)errno) {
+                        case EAGAIN:
+                        #if EAGAIN != EWOULDBLOCK
+                                case EWOULDBLOCK:
+                        #endif
+                        case EINTR:
+                                // No need to do anything special here, just assume it's a legitimate wake-up
+                                break;
+                        default:
+                                abort( "KERNEL : internal error, read failure on idle eventfd, error(%d) %s.", (int)errno, strerror( (int)errno ) );
                         }
-                #endif
-
-                __cfadbg_print_safe(runtime_core, "Kernel : core %p waiting on eventfd %d\n", this, this->idle_fd);
-
-                {
-                        eventfd_t val;
-                        ssize_t ret = read( this->idle_wctx.evfd, &val, sizeof(val) );
-                        if(ret < 0) {
-                                switch((int)errno) {
-                                case EAGAIN:
-                                #if EAGAIN != EWOULDBLOCK
-                                        case EWOULDBLOCK:
-                                #endif
-                                case EINTR:
-                                        // No need to do anything special here, just assume it's a legitimate wake-up
-                                        break;
-                                default:
-                                        abort( "KERNEL : internal error, read failure on idle eventfd, error(%d) %s.", (int)errno, strerror( (int)errno ) );
-                                }
-                        }
-                }
-
-                #if !defined(__CFA_NO_STATISTICS__)
-                        if(this->print_halts) {
-                                __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl());
-                        }
-                #endif
-        #else
-                __cfa_io_idle( this );
+                }
+        }
+
+        #if !defined(__CFA_NO_STATISTICS__)
+                if(this->print_halts) {
+                        __cfaabi_bits_print_safe( STDOUT_FILENO, "PH:%d - %lld 1\n", this->unique_id, rdtscl());
+                }
         #endif
 }
@@ -779 +764 @@
                 insert_first(this.idles, proc);
 
+                // update the pointer to the head wait context, which should now point to this proc.
                 __atomic_store_n(&this.fdw, &proc.idle_wctx, __ATOMIC_SEQ_CST);
         unlock( this );
@@ -795 +781 @@
 
                 {
+                        // update the pointer to the head wait context
                         struct __fd_waitctx * wctx = 0;
                         if(!this.idles`isEmpty) wctx = &this.idles`first.idle_wctx;

libcfa/src/concurrency/kernel.hfa

@@ -64 +64 @@
         // 1 - means the proc should wake-up immediately
         // FD - means the proc is going asleep and should be woken by writing to the FD.
+        //      The FD value should always be the evfd field just below.
         volatile int sem;
 
@@ -69 +70 @@
         int evfd;
 
-        // buffer into which the proc will read from evfd
-        // unused if not using io_uring for idle sleep
-        void * rdbuf;
-
-        // future use to track the read of the eventfd
-        // unused if not using io_uring for idle sleep
-        io_future_t * ftr;
-
+        // Used for debugging, should be removed eventually.
         volatile unsigned long long wake__time;
         volatile unsigned long long sleep_time;

libcfa/src/concurrency/kernel/private.hfa

@@ -41 +41 @@
 }
 
-// Defines whether or not we *want* to use io_uring_enter as the idle_sleep blocking call
-// #define CFA_WANT_IO_URING_IDLE
-
-// Defines whether or not we *can* use io_uring_enter as the idle_sleep blocking call
-#if defined(CFA_WANT_IO_URING_IDLE) && defined(CFA_HAVE_LINUX_IO_URING_H)
-        #if defined(CFA_HAVE_IORING_OP_READ) || (defined(CFA_HAVE_READV) && defined(CFA_HAVE_IORING_OP_READV))
-                #define CFA_WITH_IO_URING_IDLE
-        #endif
-#endif
 // #define READYQ_USE_LINEAR_AVG
 #define READYQ_USE_LOGDBL_AVG

libcfa/src/concurrency/kernel/startup.cfa

@@ -115 +115 @@
 KERNEL_STORAGE(thread$,              mainThread);
 KERNEL_STORAGE(__stack_t,            mainThreadCtx);
-// KERNEL_STORAGE(__scheduler_RWLock_t, __scheduler_lock);
-KERNEL_STORAGE(eventfd_t,            mainIdleEventFd);
-KERNEL_STORAGE(io_future_t,          mainIdleFuture);
 #if !defined(__CFA_NO_STATISTICS__)
 KERNEL_STORAGE(__stats_t, mainProcStats);
@@ -235 +232 @@
         (*mainProcessor){};
 
-        mainProcessor->idle_wctx.rdbuf = &storage_mainIdleEventFd;
-        mainProcessor->idle_wctx.ftr   = (io_future_t*)&storage_mainIdleFuture;
-        /* paranoid */ verify( sizeof(storage_mainIdleEventFd) == sizeof(eventfd_t) );
-
         __cfa_io_start( mainProcessor );
         register_tls( mainProcessor );
@@ -384 +377 @@
         register_tls( proc );
 
-        // used for idle sleep when io_uring is present
-        io_future_t future;
-        eventfd_t idle_buf;
-        proc->idle_wctx.ftr = &future;
-        proc->idle_wctx.rdbuf = &idle_buf;
+        // io_future_t future;
+        // eventfd_t idle_buf;
+        // proc->idle_wctx.ftr = &future;
+        // proc->idle_wctx.rdbuf = &idle_buf;