runtime: account stop-the-world time in the "other" GOGCTRACE section

Currently it's summed to mark phase.
The change makes it easier to diagnose long stop-the-world phases.

R=golang-dev, bradfitz, dave
CC=golang-dev
https://golang.org/cl/7182043

diff --git a/src/pkg/runtime/mgc0.c b/src/pkg/runtime/mgc0.c
index 994bb3f64cdf3b6a49b778386c8908cd930ab142..a6588954897ff8ffbf9649640f8bf8771aaf45f8 100644 (file)
--- a/src/pkg/runtime/mgc0.c
+++ b/src/pkg/runtime/mgc0.c
@@ -1474,7 +1474,7 @@ runtime·gc(int32 force)
 static void
 gc(struct gc_args *args)
 {
-       int64 t0, t1, t2, t3;
+       int64 t0, t1, t2, t3, t4;
        uint64 heap0, heap1, obj0, obj1;
        GCStats stats;
        M *mp;
@@ -1528,6 +1528,8 @@ gc(struct gc_args *args)
                runtime·helpgc(work.nproc);
        }
 
+       t1 = runtime·nanotime();
+
        runtime·parfordo(work.markfor);
        scanblock(nil, nil, 0, true);
 
@@ -1536,10 +1538,10 @@ gc(struct gc_args *args)
                        debug_scanblock(work.roots[i].p, work.roots[i].n);
                runtime·atomicstore(&work.debugmarkdone, 1);
        }
-       t1 = runtime·nanotime();
+       t2 = runtime·nanotime();
 
        runtime·parfordo(work.sweepfor);
-       t2 = runtime·nanotime();
+       t3 = runtime·nanotime();
 
        stealcache();
        cachestats(&stats);
@@ -1569,18 +1571,18 @@ gc(struct gc_args *args)
        heap1 = mstats.heap_alloc;
        obj1 = mstats.nmalloc - mstats.nfree;
 
-       t3 = runtime·nanotime();
-       mstats.last_gc = t3;
-       mstats.pause_ns[mstats.numgc%nelem(mstats.pause_ns)] = t3 - t0;
-       mstats.pause_total_ns += t3 - t0;
+       t4 = runtime·nanotime();
+       mstats.last_gc = t4;
+       mstats.pause_ns[mstats.numgc%nelem(mstats.pause_ns)] = t4 - t0;
+       mstats.pause_total_ns += t4 - t0;
        mstats.numgc++;
        if(mstats.debuggc)
-               runtime·printf("pause %D\n", t3-t0);
+               runtime·printf("pause %D\n", t4-t0);
 
        if(gctrace) {
                runtime·printf("gc%d(%d): %D+%D+%D ms, %D -> %D MB %D -> %D (%D-%D) objects,"
                                " %D(%D) handoff, %D(%D) steal, %D/%D/%D yields\n",
-                       mstats.numgc, work.nproc, (t1-t0)/1000000, (t2-t1)/1000000, (t3-t2)/1000000,
+                       mstats.numgc, work.nproc, (t2-t1)/1000000, (t3-t2)/1000000, (t1-t0+t4-t3)/1000000,
                        heap0>>20, heap1>>20, obj0, obj1,
                        mstats.nmalloc, mstats.nfree,
                        stats.nhandoff, stats.nhandoffcnt,