Datapoint: same with windows/amd64 on Intel (running 1.19beta1): goos: windows goarch: amd64 pkg: common/sandbox cpu: Intel(R) Core(TM) i7-6650U CPU @ 2.20GHz BenchmarkNoInline-4 77425848 14.34 ns/op BenchmarkInline-4 59108932 20.58 ns/op PASS ok common/sandbox 2.645s
Looking at the disassembly, I noticed that in the Inline case there was a 7-byte `lea 0xXXXXXX(%rip),%rbx` in the tight inner loop due to some really proactive constant propagation (I hypothesize). If you manually defeat the propagation by storing the string in a global and manually copying it into the stack, the inlined becomes faster than NoInline again: https://go.dev/play/p/VRgJP2y7joS goos: windows goarch: amd64 pkg: common/sandbox cpu: Intel(R) Core(TM) i7-6650U CPU @ 2.20GHz BenchmarkNoInline-4 81436539 14.08 ns/op BenchmarkInline-4 59255162 21.32 ns/op BenchmarkInlineDefeatConstProp-4 97524828 12.57 ns/op PASS ok common/sandbox 5.111s On Friday, July 22, 2022 at 11:01:00 AM UTC-6 mpr...@google.com wrote: > I can reproduce similar behavior on linux-amd64: > > $ perf stat ./example.com.test -test.bench=BenchmarkInline > -test.benchtime=100000000x > goos: linux > goarch: amd64 > pkg: example.com > cpu: Intel(R) Xeon(R) W-2135 CPU @ 3.70GHz > BenchmarkInline-12 100000000 16.78 ns/op > > PASS > > Performance counter stats for './example.com.test > -test.bench=BenchmarkInline -test.benchtime=100000000x': > > 1,691.95 msec task-clock:u # 1.004 CPUs utilized > > 0 context-switches:u # 0.000 /sec > > 0 cpu-migrations:u # 0.000 /sec > > 352 page-faults:u # 208.044 /sec > > 6,732,752,072 cycles:u # 3.979 GHz > > 22,405,823,428 instructions:u # 3.33 insn per > cycle > 6,501,294,164 branches:u # 3.842 G/sec > > 149,596 branch-misses:u # 0.00% of all > branches > > 1.684677260 seconds time elapsed > > 1.692474000 seconds user > 0.004020000 seconds sys > > > > $ perf stat ./example.com.test -test.bench=BenchmarkNoInline > -test.benchtime=100000000x > goos: linux > goarch: amd64 > pkg: example.com > cpu: Intel(R) Xeon(R) W-2135 CPU @ 3.70GHz > BenchmarkNoInline-12 100000000 10.79 ns/op > PASS > > Performance counter stats for './example.com.test > -test.bench=BenchmarkNoInline -test.benchtime=100000000x': > > 1,091.71 msec task-clock:u # 1.005 CPUs utilized > > 0 context-switches:u # 0.000 /sec > > 0 cpu-migrations:u # 0.000 /sec > > 363 page-faults:u # 332.505 /sec > > 4,490,159,750 cycles:u # 4.113 GHz > > 20,205,764,499 instructions:u # 4.50 insn per > cycle > 6,701,281,015 branches:u # 6.138 G/sec > > 586,073 branch-misses:u # 0.01% of all > branches > > 1.086302272 seconds time elapsed > > 1.087710000 seconds user > 0.008027000 seconds sys > > The non-inlined version is actually fewer instructions to run the same > benchmark, which surprises me because naively looking at the disassembly it > seems that the inlined version is much more compact. > > > On Fri, Jul 22, 2022 at 5:52 AM eric...@arm.com <eric...@arm.com> wrote: > >> For this piece of code, two test functions are the same, but one is >> inlined, the other is not. However the inlined version is about 25% slower >> than the no inlined version on apple m1 chip. Why is it? >> >> The code is here https://go.dev/play/p/0NkLMtTZtv4 >> >> -- >> You received this message because you are subscribed to the Google Groups >> "golang-nuts" group. >> To unsubscribe from this group and stop receiving emails from it, send an >> email to golang-nuts...@googlegroups.com. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/golang-nuts/527264d7-7cc1-4278-9a29-c04eb3ec4e86n%40googlegroups.com >> >> <https://groups.google.com/d/msgid/golang-nuts/527264d7-7cc1-4278-9a29-c04eb3ec4e86n%40googlegroups.com?utm_medium=email&utm_source=footer> >> . >> > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/059740f3-eaea-4d1d-bfa8-ee33ccaf9d97n%40googlegroups.com.
