Circle back on this. The forced GC turned out to be triggered by a module injected to the application code through the LD_PRELOAD. It was not the go library's internal 2 minutes GC that triggered it. It was hard to figure this out because the module was a total blackbox :) Thank you for trying to help.
On Fri, Nov 1, 2024 at 9:57 PM Ian Lance Taylor <i...@golang.org> wrote: > On Fri, Nov 1, 2024 at 9:15 PM Siyuan Liu <liusy...@gmail.com> wrote: > > > > There is this strange behavior on a Golang service we are running. > > > > On some instances, there is a forced GC that gets triggered every 4 > minutes. This can be observed when the `GODEBUG=gctrace=1` is turned on. > There is a log line with `gc ... (forced)` every 4 minutes consistently on > selected instances, with a few seconds off on each occurrence. It does not > happen on all instances. > > > > Based on the official golang documentation, `(forced)` is an indication > that `runtime.GC()` is forcefully triggered by the application code, > however, there is NO application code or third-party library code that does > `runtime.GC()`. > > > > I am wondering if golang internally does anything that might have > triggered the `runtime.GC()` - a.k.a - periodically forced GC operation? > > > > The log line that appears every 4 minutes looks something like: > > "gc 2009 @96075.949s 0%: 0.65+1314+0.13 ms clock, 39+0/19595/54342+8.2 > ms cpu, 79719->80556->42707 MB, 123241 MB goal, 2 MB stacks, 1 MB globals, > 60 P (forced)" > > Yes, in general a Go program will force a GC to occur if it has gone 2 > minutes without doing any GC at all. > > I'm not sure why you are seeing a 4 minute period, though it's > possible that I've misunderstood the code. > > Ian > -- 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 visit https://groups.google.com/d/msgid/golang-nuts/CAEGPm4JMTL6YSdyoPAksKq%2BzRT-nWjzOxABzaHiN7Jp_uRqXAA%40mail.gmail.com.
