$ go version
go version go1.8 linux/amd64 On Wednesday, May 31, 2017 at 7:13:38 AM UTC-7, Ian Lance Taylor wrote: > > [ +rlh, austin ] > > Which version of Go are you running? > > Ian > > On Tue, May 30, 2017 at 10:01 PM, Xun Liu <pas...@gmail.com <javascript:>> > wrote: > >> Hi, we see a clear correlation between GC and latency spike in our Go >> server. The server uses fairly large amount of memory (20G) and does mostly >> CPU work. The server runs on a beefy box with 32 cores and the load is >> pretty light (average CPU 20-30%). GC kicks in once every 10-20 seconds >> and whenever it runs we observe pretty big latency spike ranging from 30% >> to 100% across p50-p90 percentiles (e.g. p90 can jump from 100-120ms to >> 160-250ms) >> >> I captured a trace of a gc and noticed the following: >> >> 1. user gorountines seem run longer during gc. This is through ad-hoc >> check. I don't really know how to get stats to confirm this. >> The gc log is as following (tiny pauses but is very aggressive in assist >> and idle time) >> gc 347 @6564.164s 0%: 0.89+518+1.0 ms clock, 28+3839/4091/3959+33 ms cpu, >> 23813->23979->12265 MB, 24423 MB goal, 32 P >> >> 2. during gc, goroutines can queue up. In this particular case there is a >> stretch of time (~20ms) where we see many goroutines are GCWaiting. See >> below -- the second row is goroutines with light grey indicating GCWaiting >> count and light green Runnable. >> >> >> >> <https://lh3.googleusercontent.com/-5NWj8HzrzyI/WS5Hg0c6WiI/AAAAAAAAqL8/_P-S9vXuGU0FVZV1tG_dHX-14tDHhTsnwCLcB/s1600/Screen%2BShot%2B2017-05-30%2Bat%2B9.32.27%2BPM.png> >> >> >> <https://lh3.googleusercontent.com/-EdVRp4FjhPw/WS5MjjiwdrI/AAAAAAAAqMM/vE5Srmu9e9A5MV0d50NpDiqFsFrkn-E-QCLcB/s1600/Screen%2BShot%2B2017-05-30%2Bat%2B9.54.06%2BPM.png> >> >> Any idea what's going on here? What can I do to reduce the spikes? >> >> >> >> -- >> 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 <javascript:>. >> For more options, visit https://groups.google.com/d/optout. >> > > -- 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.
