Date: Sun, 23 May 2004 18:23:54 +0100 From: Thomas Hurst <tom.hurst@clara.net> To: freebsd-threads@freebsd.org Subject: Re: Why is MySQL nearly twice as fast on Linux? Message-ID: <20040523172354.GA97724@voi.aagh.net> In-Reply-To: <40AF4A8D.4020602@freebsd.org> References: <5.2.0.9.2.20040521154458.01627688@127.0.0.1> <5.2.0.9.2.20040521215952.0166c368@mail.ojoink.com> <40AF4A8D.4020602@freebsd.org>
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* David Xu (davidxu@freebsd.org) wrote: > I suggest you to do file system benchmark first, I suspect > -CURRENT file system's performance is far behind than Linux. The super-smack benchmarks we performed have minimal impact on filesystem; the tables are small enough to fit in cache, and systat shows clearly there's next to nothing touching the filesystem. We've tried the latest 5-RELEASE and -CURRENT as of a week or two ago; libkse (libpthread under current), libthr, libc_r and linuxthreads. System and process scope threads, linking explicitly at compile time to said libs and using libmap.conf. We've disabled HTT and tweaked everything we could think of with minimal change. I would say it *looks* like FreeBSD is only using 1 CPU, but threads are clearly distributed across them. Getting load >50% seems difficult, though. Given the number of threading libraries etc we've tried, I'm more inclined to point at scheduling or so. We did try SCHED_ULE once or twice with minimal difference. Maybe MySQL's just hitting a lot of locks *shrug*. (I'm Chris Elsworth's co-worker btw; the guy mentioned in the root of the thread :) -- Thomas 'Freaky' Hurst - freaky@aagh.net - http://www.aagh.net/
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