Changeset 5f9c42b for libcfa/src/concurrency

Timestamp:

Sep 29, 2022, 11:57:28 AM (2 years ago)

Author:

Thierry Delisle <tdelisle@…>

Branches:

ADT, ast-experimental, master

Children:

77125cc

Parents:

1756e08

Message:

Added strict flag to moving average to keep track of which timestamps need to be correct

Location:

libcfa/src/concurrency

Files:

• io.cfa (modified) (2 diffs)
• kernel/cluster.hfa (modified) (4 diffs)
• ready_queue.cfa (modified) (2 diffs)

libcfa/src/concurrency/io.cfa

@@ -201 +201 @@
                 __atomic_unlock(&ctx->cq.lock);
 
-                touch_tsc( cltr->sched.io.tscs, ctx->cq.id, ts_prev, ts_next );
+                touch_tsc( cltr->sched.io.tscs, ctx->cq.id, ts_prev, ts_next, false );
 
                 return true;
@@ -243 +243 @@
                                 /* paranoid */ verify( io.tscs[target].t.tv != ULLONG_MAX );
                                 HELP: if(target < ctxs_count) {
-                                        const unsigned long long cutoff = calc_cutoff(ctsc, ctx->cq.id, ctxs_count, io.data, io.tscs, __shard_factor.io);
-                                        const unsigned long long age = moving_average(ctsc, io.tscs[target].t.tv, io.tscs[target].t.ma);
+                                        const unsigned long long cutoff = calc_cutoff(ctsc, ctx->cq.id, ctxs_count, io.data, io.tscs, __shard_factor.io, false);
+                                        const unsigned long long age = moving_average(ctsc, io.tscs[target].t.tv, io.tscs[target].t.ma, false);
                                         __cfadbg_print_safe(io, "Kernel I/O: Help attempt on %u from %u, age %'llu vs cutoff %'llu, %s\n", target, ctx->cq.id, age, cutoff, age > cutoff ? "yes" : "no");
                                         if(age <= cutoff) break HELP;

libcfa/src/concurrency/kernel/cluster.hfa

@@ -23 +23 @@
 //-----------------------------------------------------------------------
 // Calc moving average based on existing average, before and current time.
-static inline unsigned long long moving_average(unsigned long long currtsc, unsigned long long instsc, unsigned long long old_avg) {
-        /* paranoid */ verifyf( old_avg < 15000000000000, "Suspiciously large previous average: %'llu (%llx)\n", old_avg, old_avg );
+static inline unsigned long long moving_average(unsigned long long currtsc, unsigned long long instsc, unsigned long long old_avg, bool strict) {
+        (void)strict; // disable the warning around the fact this is unused in release.
 
         const unsigned long long new_val = currtsc > instsc ? currtsc - instsc : 0;
@@ -34 +34 @@
 }
 
-static inline void touch_tsc(__timestamp_t * tscs, size_t idx, unsigned long long ts_prev, unsigned long long ts_next) {
+static inline void touch_tsc(__timestamp_t * tscs, size_t idx, unsigned long long ts_prev, unsigned long long ts_next, bool strict) {
         if (ts_next == ULLONG_MAX) return;
         unsigned long long now = rdtscl();
         unsigned long long pma = __atomic_load_n(&tscs[ idx ].t.ma, __ATOMIC_RELAXED);
         __atomic_store_n(&tscs[ idx ].t.tv, ts_next, __ATOMIC_RELAXED);
-        __atomic_store_n(&tscs[ idx ].t.ma, moving_average(now, ts_prev, pma), __ATOMIC_RELAXED);
+        __atomic_store_n(&tscs[ idx ].t.ma, moving_average(now, ts_prev, pma, strict), __ATOMIC_RELAXED);
 }
 
@@ -51 +51 @@
         Data_t * data,
         __timestamp_t * tscs,
-        const unsigned shard_factor
+        const unsigned shard_factor,
+        bool strict
 ) {
         unsigned start = procid;
@@ -59 +60 @@
                 if(ptsc != ULLONG_MAX) {
                         /* paranoid */ verify( start + i < count );
-                        unsigned long long tsc = moving_average(ctsc, ptsc, tscs[start + i].t.ma);
+                        unsigned long long tsc = moving_average(ctsc, ptsc, tscs[start + i].t.ma, strict);
                         if(tsc > max) max = tsc;
                 }

libcfa/src/concurrency/ready_queue.cfa

@@ -139 +139 @@
                 /* paranoid */ verify( readyQ.tscs[target].t.tv != ULLONG_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].t.tv, readyQ.tscs[target].t.ma);
+                        const unsigned long long cutoff = calc_cutoff(ctsc, proc->rdq.id, lanes_count, cltr->sched.readyQ.data, cltr->sched.readyQ.tscs, __shard_factor.readyq, true);
+                        const unsigned long long age = moving_average(ctsc, readyQ.tscs[target].t.tv, readyQ.tscs[target].t.ma, false);
                         __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) {
@@ -214 +214 @@
         __STATS( stats.success++; )
 
-        touch_tsc(readyQ.tscs, w, ts_prev, ts_next);
+        touch_tsc(readyQ.tscs, w, ts_prev, ts_next, true);
 
         thrd->preferred = w / __shard_factor.readyq;