Date: Tue, 29 Nov 2016 09:28:18 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 214923] kqueue hangs with busy loop Message-ID: <bug-214923-8-SdvjheSNmp@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-214923-8@https.bugs.freebsd.org/bugzilla/> References: <bug-214923-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=214923 Konstantin Belousov <kib@FreeBSD.org> changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |kib@FreeBSD.org --- Comment #1 from Konstantin Belousov <kib@FreeBSD.org> --- (In reply to yjh0502 from comment #0) I do not see a clean indicator that the process 'spins on the kqueue syscall'. The wait channel demonstrates that the process waits for some event subsystem mutex (the star before the name), but due to the truncated output, I am not sure which mutex is it. It could kqueue lock, or kqueue global lock, for instance. That said, WCPU 100% indicates that there is some other thread in the process which consumes cycles, which is consistent with the report of four threads in the process. >From that data, I am not even convinced that this is a kernel bug and not some application issue. For very beginning, look at the kernel backtraces of all threads in your process with procstat -kk. Find and backtrace the lock owner of a kqueue lock. All that assuming that you believe that the issue is a kernel problem. Otherwise, and I would start with that route, would I debug it myself, is to look at the app and see what it is doing (wrong). -- You are receiving this mail because: You are the assignee for the bug.help
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