cmd/compile: adjust PGO inlining default parameters

Adjust PGO inlining default parameters to 99% CDF threshold and
2000 budget. Benchmark results (mostly from Sweet) show that this
set of parameters performs reasonably well, with a few percent
speedup at the cost of a few percent binary size increase.

Also rename the debug flags to start with "pgo", to make it clear
that they are related to PGO.

Change-Id: I0749249b1298d1dc55a28993c37b3185f9d7639d
Reviewed-on: https://go-review.googlesource.com/c/go/+/449477
Run-TryBot: Cherry Mui <cherryyz@google.com>
Reviewed-by: Michael Pratt <mpratt@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>

diff --git a/src/cmd/compile/internal/base/debug.go b/src/cmd/compile/internal/base/debug.go
index 7e4adef70695367da7613c28c5ec67057e769502..ca3552733deb065feab3b9748e24bb126aedd268 100644 (file)
--- a/src/cmd/compile/internal/base/debug.go
+++ b/src/cmd/compile/internal/base/debug.go
@@ -16,41 +16,41 @@ var Debug DebugFlags
 // The -d option takes a comma-separated list of settings.
 // Each setting is name=value; for ints, name is short for name=1.
 type DebugFlags struct {
-       Append                        int    `help:"print information about append compilation"`
-       Checkptr                      int    `help:"instrument unsafe pointer conversions\n0: instrumentation disabled\n1: conversions involving unsafe.Pointer are instrumented\n2: conversions to unsafe.Pointer force heap allocation" concurrent:"ok"`
-       Closure                       int    `help:"print information about closure compilation"`
-       DclStack                      int    `help:"run internal dclstack check"`
-       Defer                         int    `help:"print information about defer compilation"`
-       DisableNil                    int    `help:"disable nil checks" concurrent:"ok"`
-       DumpPtrs                      int    `help:"show Node pointers values in dump output"`
-       DwarfInl                      int    `help:"print information about DWARF inlined function creation"`
-       Export                        int    `help:"print export data"`
-       Fmahash                       string `help:"hash value for use in debugging platform-dependent multiply-add use" concurrent:"ok"`
-       GCAdjust                      int    `help:"log adjustments to GOGC" concurrent:"ok"`
-       GCProg                        int    `help:"print dump of GC programs"`
-       Gossahash                     string `help:"hash value for use in debugging the compiler"`
-       InlFuncsWithClosures          int    `help:"allow functions with closures to be inlined" concurrent:"ok"`
-       Libfuzzer                     int    `help:"enable coverage instrumentation for libfuzzer"`
-       LocationLists                 int    `help:"print information about DWARF location list creation"`
-       Nil                           int    `help:"print information about nil checks"`
-       NoOpenDefer                   int    `help:"disable open-coded defers" concurrent:"ok"`
-       NoRefName                     int    `help:"do not include referenced symbol names in object file" concurrent:"ok"`
-       PCTab                         string `help:"print named pc-value table\nOne of: pctospadj, pctofile, pctoline, pctoinline, pctopcdata"`
-       Panic                         int    `help:"show all compiler panics"`
-       Reshape                       int    `help:"print information about expression reshaping"`
-       Shapify                       int    `help:"print information about shaping recursive types"`
-       Slice                         int    `help:"print information about slice compilation"`
-       SoftFloat                     int    `help:"force compiler to emit soft-float code" concurrent:"ok"`
-       SyncFrames                    int    `help:"how many writer stack frames to include at sync points in unified export data"`
-       TypeAssert                    int    `help:"print information about type assertion inlining"`
-       TypecheckInl                  int    `help:"eager typechecking of inline function bodies" concurrent:"ok"`
-       Unified                       int    `help:"enable unified IR construction"`
-       WB                            int    `help:"print information about write barriers"`
-       ABIWrap                       int    `help:"print information about ABI wrapper generation"`
-       MayMoreStack                  string `help:"call named function before all stack growth checks" concurrent:"ok"`
-       InlineHotCallSiteCDFThreshold string `help:"cummulative threshold percentage for determining call sites as hot candidates for inlining" concurrent:"ok"`
-       InlineHotBudget               int    `help:"inline budget for hot functions" concurrent:"ok"`
-       PGOInline                     int    `help:"debug profile-guided inlining"`
+       Append                int    `help:"print information about append compilation"`
+       Checkptr              int    `help:"instrument unsafe pointer conversions\n0: instrumentation disabled\n1: conversions involving unsafe.Pointer are instrumented\n2: conversions to unsafe.Pointer force heap allocation" concurrent:"ok"`
+       Closure               int    `help:"print information about closure compilation"`
+       DclStack              int    `help:"run internal dclstack check"`
+       Defer                 int    `help:"print information about defer compilation"`
+       DisableNil            int    `help:"disable nil checks" concurrent:"ok"`
+       DumpPtrs              int    `help:"show Node pointers values in dump output"`
+       DwarfInl              int    `help:"print information about DWARF inlined function creation"`
+       Export                int    `help:"print export data"`
+       Fmahash               string `help:"hash value for use in debugging platform-dependent multiply-add use" concurrent:"ok"`
+       GCAdjust              int    `help:"log adjustments to GOGC" concurrent:"ok"`
+       GCProg                int    `help:"print dump of GC programs"`
+       Gossahash             string `help:"hash value for use in debugging the compiler"`
+       InlFuncsWithClosures  int    `help:"allow functions with closures to be inlined" concurrent:"ok"`
+       Libfuzzer             int    `help:"enable coverage instrumentation for libfuzzer"`
+       LocationLists         int    `help:"print information about DWARF location list creation"`
+       Nil                   int    `help:"print information about nil checks"`
+       NoOpenDefer           int    `help:"disable open-coded defers" concurrent:"ok"`
+       NoRefName             int    `help:"do not include referenced symbol names in object file" concurrent:"ok"`
+       PCTab                 string `help:"print named pc-value table\nOne of: pctospadj, pctofile, pctoline, pctoinline, pctopcdata"`
+       Panic                 int    `help:"show all compiler panics"`
+       Reshape               int    `help:"print information about expression reshaping"`
+       Shapify               int    `help:"print information about shaping recursive types"`
+       Slice                 int    `help:"print information about slice compilation"`
+       SoftFloat             int    `help:"force compiler to emit soft-float code" concurrent:"ok"`
+       SyncFrames            int    `help:"how many writer stack frames to include at sync points in unified export data"`
+       TypeAssert            int    `help:"print information about type assertion inlining"`
+       TypecheckInl          int    `help:"eager typechecking of inline function bodies" concurrent:"ok"`
+       Unified               int    `help:"enable unified IR construction"`
+       WB                    int    `help:"print information about write barriers"`
+       ABIWrap               int    `help:"print information about ABI wrapper generation"`
+       MayMoreStack          string `help:"call named function before all stack growth checks" concurrent:"ok"`
+       PGOInlineCDFThreshold string `help:"cummulative threshold percentage for determining call sites as hot candidates for inlining" concurrent:"ok"`
+       PGOInlineBudget       int    `help:"inline budget for hot functions" concurrent:"ok"`
+       PGOInline             int    `help:"debug profile-guided inlining"`
 
        ConcurrentOk bool // true if only concurrentOk flags seen
 }

diff --git a/src/cmd/compile/internal/inline/inl.go b/src/cmd/compile/internal/inline/inl.go
index aebe32869a94e34721953276d6ba3cc126c9ecdd..028b6c0e83da7a4c7ce0787b213f1d05d08e85a0 100644 (file)
--- a/src/cmd/compile/internal/inline/inl.go
+++ b/src/cmd/compile/internal/inline/inl.go
@@ -76,15 +76,15 @@ var (
        // that is, for a threshold of X the hottest callsites that
        // make up the top X% of total edge weight will be
        // considered hot for inlining candidates.
-       inlineCDFHotCallSiteThresholdPercent = float64(95)
+       inlineCDFHotCallSiteThresholdPercent = float64(99)
 
        // Budget increased due to hotness.
-       inlineHotMaxBudget int32 = 160
+       inlineHotMaxBudget int32 = 2000
 )
 
 // pgoInlinePrologue records the hot callsites from ir-graph.
 func pgoInlinePrologue(p *pgo.Profile, decls []ir.Node) {
-       if s, err := strconv.ParseFloat(base.Debug.InlineHotCallSiteCDFThreshold, 64); err == nil {
+       if s, err := strconv.ParseFloat(base.Debug.PGOInlineCDFThreshold, 64); err == nil {
                inlineCDFHotCallSiteThresholdPercent = s
        }
        var hotCallsites []pgo.NodeMapKey
@@ -93,8 +93,8 @@ func pgoInlinePrologue(p *pgo.Profile, decls []ir.Node) {
                fmt.Printf("hot-callsite-thres-from-CDF=%v\n", inlineHotCallSiteThresholdPercent)
        }
 
-       if base.Debug.InlineHotBudget != 0 {
-               inlineHotMaxBudget = int32(base.Debug.InlineHotBudget)
+       if x := base.Debug.PGOInlineBudget; x != 0 {
+               inlineHotMaxBudget = int32(x)
        }
 
        // mark inlineable callees from hot edges

diff --git a/src/cmd/compile/internal/test/pgo_inl_test.go b/src/cmd/compile/internal/test/pgo_inl_test.go
index d0737f76a1aae61b8c2ea2ae7b55255bb4a7a2b2..ea2e00ce38c600cdbd24f4199f5e3a950f21f56e 100644 (file)
--- a/src/cmd/compile/internal/test/pgo_inl_test.go
+++ b/src/cmd/compile/internal/test/pgo_inl_test.go
@@ -67,9 +67,10 @@ go 1.19
                expectedNotInlinedList[fullName] = struct{}{}
        }
 
-       // go test -c -o /tmp/test.exe -cpuprofile inline_hot.pprof
+       // Build the test with the profile. Use a smaller threshold to test.
+       // TODO: maybe adjust the test to work with default threshold.
        pprof := filepath.Join(dir, "inline_hot.pprof")
-       gcflag := fmt.Sprintf("-gcflags=-m -m -pgoprofile %s", pprof)
+       gcflag := fmt.Sprintf("-gcflags=-m -m -pgoprofile=%s -d=pgoinlinebudget=160,pgoinlinecdfthreshold=90", pprof)
        out := filepath.Join(dir, "test.exe")
        cmd := testenv.CleanCmdEnv(exec.Command(testenv.GoToolPath(t), "test", "-c", "-o", out, gcflag, "."))
        cmd.Dir = dir