The 17% is sleeping. The 70% is garbage collection. On Wednesday, January 12, 2022 at 3:54:32 PM UTC-6 st...@rothskeller.net wrote:
> I am attempting to profile my code, and I'm unable to interpret the > results. So first, the meta-question is, what's the best forum to use to > request help with such things? > > The code I'm profiling is the server side of a moderately complex webapp. > For simplicity, I've wrapped it with net/http/cgi and am calling it from > the command line as a CGI "script". As such, it is handling a single > request with no actual network traffic. Also, I've disabled the garbage > collector. I'm calling pprof.StartCPUProfile at the top of ServeHTTP. The > pprof output is at > > https://scholacantorum.org/pprof.svg > > It shows three different call chains. The one that actually includes my > code, starting at runtime.main, is only 6% of the total CPU samples. There > are two other call chains that are entirely within the runtime package, one > of them taking 17% of the time and the other taking a whopping 70% of the > time, and I can't figure out what they're doing. I would appreciate any > guidance. > > The chain that is taking 70% of the time is > > gcBgMarkWorker > > systemstack > > gcBgMarkWorker.func2 > > gcDrain > > markroot > > markroot.func1 > > suspendG > > Underneath suspendG it splits into nanotime, osyield, procyield, and > preemptM, the latter of which has signalM, tgkill, and getpid children. > getpid alone is shown as taking 4% of the CPU of the entire program! What > the heck is this call chain doing, with nearly three quarters of my time? > > The chain that is taking 17% of the time is > > mcall > > park_m > > schedule > > findrunnable > > stopm > > mPark > > notesleep > > futexsleep > > futex > > Again I have no clue what this is doing. Any guidance is welcome, > including pointers to other forums better suited for such questions. > > Regards, > Steve > > -- 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/1e1ce42b-fea3-4247-9d20-558caed4093bn%40googlegroups.com.
