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Nick Piggin wrote: > On Tuesday 04 March 2008 06:02, Cyrus Massoumi wrote: >> Nick Piggin wrote: >>> On Saturday 01 March 2008 01:54, Diego Calleja wrote: >>>> El Fri, 29 Feb 2008 08:38:00 -0500, "Stephen Cuppett" >>>> <cuppett@gmail.com> >>> escribió: >>>>> loads and 1500% at high loads. When compared with the best performing >>>>> Linux kernel (2.6.22 or 2.6.24) performance is 15% better. Results are >>>> There has been some performance problems with sysbench performance in >>>> linux which made it slower than freebsd, there were some patches to >>>> speed things up, not sure if they have been merged. >>> There definitely were performance problems with threaded malloc/free >>> in the Linux kernel and glibc. Fixes have been merged in both packages, >>> and AFAIK the FreeBSD guys tested with those fixes in place. >>> >>> I think these were never really run into before in part due to MySQL's >>> unscalable heap design makes it not scale well on higher numbers of >>> CPUs anyway, and also made the malloc problems more pronounced (ie. >>> they added a bit to the contention of the single heap lock, which is >>> the big killer here). >> IIRC, going to fine-grained file locking gave them a huge boost in this >> particular benchmark (and maybe others). >> As I said on lwn.net Peter Zijlstra posted a patch to break the global >> file list lock about a year ago [1], but I don't think it was ever >> merged. Here [2] are some numbers for the patchset. >> >> [1] http://lkml.org/lkml/2007/1/28/29 >> [2] http://lkml.org/lkml/2007/1/28/116 > > The mysql workload is not constrained by this lock. The important > part (where freebsd saw their gain) is probably fd lookups, which > are lockless in Linux for a long time. Thanks for pointing this out Nick. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ | ||||||||||
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