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.
