Date: Tue, 20 Feb 2007 17:29:17 -0500 (EST) From: Daniel Eischen <deischen@freebsd.org> To: Martin Blapp <mb@imp.ch> Cc: rob@debank.tv, freebsd-threads@freebsd.org Subject: Re: 6.2-Release and Clamd 0.90 with libpthread.so Message-ID: <Pine.GSO.4.64.0702201724590.12034@sea.ntplx.net> In-Reply-To: <20070220225303.V4139@godot.imp.ch> References: <20070220153632.E4139@godot.imp.ch> <Pine.GSO.4.64.0702201138080.12034@sea.ntplx.net> <20070220174221.B4139@godot.imp.ch> <Pine.GSO.4.64.0702201145420.12034@sea.ntplx.net> <20070220190347.C4139@godot.imp.ch> <Pine.GSO.4.64.0702201319230.12034@sea.ntplx.net> <20070220225303.V4139@godot.imp.ch>
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On Tue, 20 Feb 2007, Martin Blapp wrote: > Hi, > >> Also try setting kern.threads.virtual_cpu=1 if you have >> more than 1 cpu (this will limit it to 1 KSE). > > Our boxes have 2 CPUs and HTT is activated. > > Interesting. With kern.threads.virtual_cpu=1 it works also > in the libpthread case, but while there are still some fork() calls > it works better. With kern.threads.virtual_cpu=2 it's slower. And > With kern.threads.virtual_cpu=4 its really slow. > > If I run clamd in foreground mode everything works as it should. > More interesting, the CPU load drops significantly (500-1000%) ! > > Something is seriosly broken here. Running in foreground with or without kern.threads.virtual_cpu adjusted? If running in foreground works regardless of kern.threads.virtual_cpu (there will still be some inefficiencies here because of the scheduler and KSE overhead/contention), then it is probably due to the application doing a fork() from a threaded application without doing an exec(). This is prohibited by POSIX and libpthread makes no attempt to allow it. -- DE
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