Date: Tue, 15 Nov 2011 11:07:45 +0200 From: Kostik Belousov <kostikbel@gmail.com> To: Doug Barton <dougb@freebsd.org> Cc: Daniil Cherednik <dcherednik@masterhost.ru>, freebsd-stable@freebsd.org Subject: Re: 8.2 + apache == a LOT of sigprocmask Message-ID: <20111115090745.GO50300@deviant.kiev.zoral.com.ua> In-Reply-To: <4EC17F57.5030008@FreeBSD.org> References: <4EC17AAF.9050807@FreeBSD.org> <4EC17F57.5030008@FreeBSD.org>
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[-- Attachment #1 --] On Mon, Nov 14, 2011 at 12:51:35PM -0800, Doug Barton wrote: > On 11/14/2011 12:31, Doug Barton wrote: > > Trying to track down a load problem we're seeing on 8.2-RELEASE-p4 i386 > > in a busy web hosting environment I came across the following post: > > > > http://lists.freebsd.org/pipermail/freebsd-questions/2011-October/234520.html > > > > That basically describes what we're seeing as well, including the > > "doesn't happen on Linux" part. > > > > Does anyone have any ideas about this? > > > > With incredibly similar stuff running on 7.x we didn't see this problem, > > so it seems to be something new in 8. > > Just took a closer look at our ktrace, and actually our pattern is > slightly different than the one in that post. In ours the second option > is null, but the third is set: > > 74195 httpd 0.000017 RET sigprocmask 0 > 74195 httpd 0.000013 CALL sigprocmask(SIG_BLOCK,0,0xbfbf89d4) > 74195 httpd 0.000009 RET sigprocmask 0 > 74195 httpd 0.000013 CALL sigprocmask(SIG_BLOCK,0,0xbfbf89d4) > 74195 httpd 0.000009 RET sigprocmask 0 > 74195 httpd 0.000012 CALL sigprocmask(SIG_BLOCK,0,0xbfbf89d4) > > But repeated hundreds of times in a row. The calls cannot come from rtld, they are generated by some setjmp() invocation. If signal-safety is not needed, sigsetjmp() should be used instead. Quick grep of the apache httpd source shows a single setjmp() in their copy of pcre. No idea is it to safe to change setjmp() into sigsetjmp(?, 0). [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (FreeBSD) iEUEARECAAYFAk7CK+EACgkQC3+MBN1Mb4g34ACeIehqW4571CMhvULXoPb/YAmr eCMAl2asO0EOax3iKkh0SMh81Y/X5Og= =TdFv -----END PGP SIGNATURE-----
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