Thanks for pointing issues out I updated my code to get rid of race conditions (nothing critical I was always doing reader-writer race). Anyhow I updated my code on https://gist.github.com/maxpert/f3c405c516ba2d4c8aa8b0695e0e054e. Still doesn't explain the new results:
$> go test -race -run=! -bench=. -benchmem -cpu=1,2,4,8 -cpuprofile=cpu.out -memprofile=mem.out pubsub_test.go BenchmarkPubSubPrimitiveChannelsMultiple 50 21121694 ns/op 8515 B/op 39 allocs/op BenchmarkPubSubPrimitiveChannelsMultiple-2 100 19302372 ns/op 4277 B/op 20 allocs/op BenchmarkPubSubPrimitiveChannelsMultiple-4 50 22674769 ns/op 8182 B/op 35 allocs/op BenchmarkPubSubPrimitiveChannelsMultiple-8 50 21201533 ns/op 8469 B/op 38 allocs/op BenchmarkPubSubWaitGroupMultiple 3000 501804 ns/op 63 B/op 2 allocs/op BenchmarkPubSubWaitGroupMultiple-2 200 15417944 ns/op 407 B/op 6 allocs/op BenchmarkPubSubWaitGroupMultiple-4 300 5010273 ns/op 231 B/op 4 allocs/op BenchmarkPubSubWaitGroupMultiple-8 200 5444634 ns/op 334 B/op 5 allocs/op PASS ok command-line-arguments 21.775s So far my testing shows channels are slower for pubsub scenario. I tried looking into pprof dumps of memory and CPU and it's not making sense to me. What am I missing here? On Sunday, July 16, 2017 at 10:27:04 AM UTC-7, peterGo wrote: > > When you have data races the results are undefined. > > $ go version > go version devel +dd81c37 Sat Jul 15 05:43:45 2017 +0000 linux/amd64 > $ go test -race -run=! -bench=. -benchmem -cpu=1,2,4,8 pubsub_test.go > ================== > WARNING: DATA RACE > Read at 0x00c4200140c0 by goroutine 18: > command-line-arguments.BenchmarkPubSubPrimitiveChannelsMultiple() > /home/peter/gopath/src/nuts/pubsub_test.go:59 +0x51d > testing.(*B).runN() > /home/peter/go/src/testing/benchmark.go:141 +0x12a > testing.(*B).run1.func1() > /home/peter/go/src/testing/benchmark.go:214 +0x6b > > Previous write at 0x00c4200140c0 by goroutine 57: > [failed to restore the stack] > > Goroutine 18 (running) created at: > testing.(*B).run1() > /home/peter/go/src/testing/benchmark.go:207 +0x8c > testing.(*B).Run() > /home/peter/go/src/testing/benchmark.go:513 +0x482 > testing.runBenchmarks.func1() > /home/peter/go/src/testing/benchmark.go:417 +0xa7 > testing.(*B).runN() > /home/peter/go/src/testing/benchmark.go:141 +0x12a > testing.runBenchmarks() > /home/peter/go/src/testing/benchmark.go:423 +0x86d > testing.(*M).Run() > /home/peter/go/src/testing/testing.go:928 +0x51e > main.main() > command-line-arguments/_test/_testmain.go:46 +0x1d3 > > Goroutine 57 (finished) created at: > command-line-arguments.BenchmarkPubSubPrimitiveChannelsMultiple() > /home/peter/gopath/src/nuts/pubsub_test.go:40 +0x290 > testing.(*B).runN() > /home/peter/go/src/testing/benchmark.go:141 +0x12a > testing.(*B).run1.func1() > /home/peter/go/src/testing/benchmark.go:214 +0x6b > ================== > --- FAIL: BenchmarkPubSubPrimitiveChannelsMultiple > benchmark.go:147: race detected during execution of benchmark > ================== > WARNING: DATA RACE > Read at 0x00c42000c030 by goroutine 1079: > command-line-arguments.BenchmarkPubSubWaitGroupMultiple.func1() > /home/peter/gopath/src/nuts/pubsub_test.go:76 +0x9e > > Previous write at 0x00c42000c030 by goroutine 7: > command-line-arguments.BenchmarkPubSubWaitGroupMultiple() > /home/peter/gopath/src/nuts/pubsub_test.go:101 +0x475 > testing.(*B).runN() > /home/peter/go/src/testing/benchmark.go:141 +0x12a > testing.(*B).run1.func1() > /home/peter/go/src/testing/benchmark.go:214 +0x6b > > Goroutine 1079 (running) created at: > command-line-arguments.BenchmarkPubSubWaitGroupMultiple() > /home/peter/gopath/src/nuts/pubsub_test.go:93 +0x2e6 > testing.(*B).runN() > /home/peter/go/src/testing/benchmark.go:141 +0x12a > testing.(*B).run1.func1() > /home/peter/go/src/testing/benchmark.go:214 +0x6b > > Goroutine 7 (running) created at: > testing.(*B).run1() > /home/peter/go/src/testing/benchmark.go:207 +0x8c > testing.(*B).Run() > /home/peter/go/src/testing/benchmark.go:513 +0x482 > testing.runBenchmarks.func1() > /home/peter/go/src/testing/benchmark.go:417 +0xa7 > testing.(*B).runN() > /home/peter/go/src/testing/benchmark.go:141 +0x12a > testing.runBenchmarks() > /home/peter/go/src/testing/benchmark.go:423 +0x86d > testing.(*M).Run() > /home/peter/go/src/testing/testing.go:928 +0x51e > main.main() > command-line-arguments/_test/_testmain.go:46 +0x1d3 > ================== > ================== > WARNING: DATA RACE > Write at 0x00c42000c030 by goroutine 7: > command-line-arguments.BenchmarkPubSubWaitGroupMultiple() > /home/peter/gopath/src/nuts/pubsub_test.go:101 +0x475 > testing.(*B).runN() > /home/peter/go/src/testing/benchmark.go:141 +0x12a > testing.(*B).run1.func1() > /home/peter/go/src/testing/benchmark.go:214 +0x6b > > Previous read at 0x00c42000c030 by goroutine 1078: > command-line-arguments.BenchmarkPubSubWaitGroupMultiple.func1() > /home/peter/gopath/src/nuts/pubsub_test.go:76 +0x9e > > Goroutine 7 (running) created at: > testing.(*B).run1() > /home/peter/go/src/testing/benchmark.go:207 +0x8c > testing.(*B).Run() > /home/peter/go/src/testing/benchmark.go:513 +0x482 > testing.runBenchmarks.func1() > /home/peter/go/src/testing/benchmark.go:417 +0xa7 > testing.(*B).runN() > /home/peter/go/src/testing/benchmark.go:141 +0x12a > testing.runBenchmarks() > /home/peter/go/src/testing/benchmark.go:423 +0x86d > testing.(*M).Run() > /home/peter/go/src/testing/testing.go:928 +0x51e > main.main() > command-line-arguments/_test/_testmain.go:46 +0x1d3 > > Goroutine 1078 (running) created at: > command-line-arguments.BenchmarkPubSubWaitGroupMultiple() > /home/peter/gopath/src/nuts/pubsub_test.go:93 +0x2e6 > testing.(*B).runN() > /home/peter/go/src/testing/benchmark.go:141 +0x12a > testing.(*B).run1.func1() > /home/peter/go/src/testing/benchmark.go:214 +0x6b > ================== > ================== > WARNING: DATA RACE > Read at 0x00c4200140c8 by goroutine 7: > command-line-arguments.BenchmarkPubSubWaitGroupMultiple() > /home/peter/gopath/src/nuts/pubsub_test.go:109 +0x51d > testing.(*B).runN() > /home/peter/go/src/testing/benchmark.go:141 +0x12a > testing.(*B).run1.func1() > /home/peter/go/src/testing/benchmark.go:214 +0x6b > > Previous write at 0x00c4200140c8 by goroutine 175: > sync/atomic.AddInt64() > /home/peter/go/src/runtime/race_amd64.s:276 +0xb > command-line-arguments.BenchmarkPubSubWaitGroupMultiple.func1() > /home/peter/gopath/src/nuts/pubsub_test.go:88 +0x19a > > Goroutine 7 (running) created at: > testing.(*B).run1() > /home/peter/go/src/testing/benchmark.go:207 +0x8c > testing.(*B).Run() > /home/peter/go/src/testing/benchmark.go:513 +0x482 > testing.runBenchmarks.func1() > /home/peter/go/src/testing/benchmark.go:417 +0xa7 > testing.(*B).runN() > /home/peter/go/src/testing/benchmark.go:141 +0x12a > testing.runBenchmarks() > /home/peter/go/src/testing/benchmark.go:423 +0x86d > testing.(*M).Run() > /home/peter/go/src/testing/testing.go:928 +0x51e > main.main() > command-line-arguments/_test/_testmain.go:46 +0x1d3 > > Goroutine 175 (finished) created at: > command-line-arguments.BenchmarkPubSubWaitGroupMultiple() > /home/peter/gopath/src/nuts/pubsub_test.go:93 +0x2e6 > testing.(*B).runN() > /home/peter/go/src/testing/benchmark.go:141 +0x12a > testing.(*B).run1.func1() > /home/peter/go/src/testing/benchmark.go:214 +0x6b > ================== > --- FAIL: BenchmarkPubSubWaitGroupMultiple > benchmark.go:147: race detected during execution of benchmark > FAIL > exit status 1 > FAIL command-line-arguments 0.726s > $ > > Peter > > On Sunday, July 16, 2017 at 10:20:21 AM UTC-4, Zohaib Sibte Hassan wrote: >> >> I have been spending my day over implementing an efficient PubSub system. >> I had implemented one before using channels, and I wanted to benchmark that >> against sync.Cond. Here is the quick and dirty test that I put together >> https://gist.github.com/maxpert/f3c405c516ba2d4c8aa8b0695e0e054e. Now my >> confusion starts when I change GOMAXPROCS to test how it would perform on >> my age old Raspberry Pi. Here are results: >> >> mxp@carbon:~/repos/raspchat/src/sibte.so/rascore$ GOMAXPROCS=8 go test >> -run none -bench Multiple -cpuprofile=cpu.out -memprofile=mem.out -benchmem >> BenchmarkPubSubPrimitiveChannelsMultiple-8 10000 165419 ns/op >> 92 B/op 2 allocs/op >> BenchmarkPubSubWaitGroupMultiple-8 10000 204685 ns/op >> 53 B/op 2 allocs/op >> PASS >> ok sibte.so/rascore 3.749s >> mxp@carbon:~/repos/raspchat/src/sibte.so/rascore$ GOMAXPROCS=4 go test >> -run none -bench Multiple -cpuprofile=cpu.out -memprofile=mem.out -benchmem >> BenchmarkPubSubPrimitiveChannelsMultiple-4 20000 101704 ns/op >> 60 B/op 2 allocs/op >> BenchmarkPubSubWaitGroupMultiple-4 10000 204039 ns/op >> 52 B/op 2 allocs/op >> PASS >> ok sibte.so/rascore 5.087s >> mxp@carbon:~/repos/raspchat/src/sibte.so/rascore$ GOMAXPROCS=2 go test >> -run none -bench Multiple -cpuprofile=cpu.out -memprofile=mem.out -benchmem >> BenchmarkPubSubPrimitiveChannelsMultiple-2 30000 51255 ns/op >> 54 B/op 2 allocs/op >> BenchmarkPubSubWaitGroupMultiple-2 20000 60871 ns/op >> 43 B/op 2 allocs/op >> PASS >> ok sibte.so/rascore 4.022s >> mxp@carbon:~/repos/raspchat/src/sibte.so/rascore$ GOMAXPROCS=1 go test >> -run none -bench Multiple -cpuprofile=cpu.out -memprofile=mem.out -benchmem >> BenchmarkPubSubPrimitiveChannelsMultiple 20000 79534 ns/op 61 >> B/op 2 allocs/op >> BenchmarkPubSubWaitGroupMultiple 100000 19066 ns/op 40 >> B/op 2 allocs/op >> PASS >> ok sibte.so/rascore 4.502s >> >> I tried multiple times and results are consistent. I am using Go 1.8, >> Linux x64, 8GB RAM. I have multiple questions: >> >> >> - Why do channels perform worst than sync.Cond in single core >> results? Context switching is same if anything it should perform worst. >> - As I increase the max procs the sync.Cond results go down which >> might be explainable, but what is up with channels? 20k to 30k to 20k to >> 10k :( I have a i5 with 4 cores, so it should have peaked at 4 procs >> (pst. >> I tried 3 as well it's consistent). >> >> I am still suspicious I am not making some kind of mistake in code. Any >> ideas? >> >> - Thanks >> > -- 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. For more options, visit https://groups.google.com/d/optout.
