Messages in this thread | | | Subject | Re: Nick's vfs-scalability patches ported to 2.6.33-rt | From | john stultz <> | Date | Tue, 09 Mar 2010 18:51:02 -0800 |
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On Wed, 2010-03-03 at 20:05 -0800, john stultz wrote: > Thomas: I ran a number of kernel-bench and dbench stress tests on this > today and I've not seen any issues, so unless Nick has other issues, I > think it should be ok to pull into -rt. > > You can grab the full patchset that builds ontop of 2.6.33-rt4 here: > http://sr71.net/~jstultz/dbench-scalability/patches/2.6.33-rt4/vfs-scale.33-rt.tar.bz2
Oh, and another interesting data point!
The ext2 performance numbers with this patch set are scaling better then the 2.6.31-rt-vfs set earlier tested!
http://sr71.net/~jstultz/dbench-scalability/graphs/2.6.33/ext2-dbench.png
Its not perfect, but its closing the gap. More interestingly, where as we were still seeing path lookup contention in 2.6.31, its not showing up in the perf logs with 2.6.33. Instead, the contention is on the ext2 group_adjust_blocks function.
And replacing the statvfs call in dbench with statfs pushes the results past mainline: http://sr71.net/~jstultz/dbench-scalability/graphs/2.6.33/ext2-dbench-statfs.png
So this all means that with Nick's patch set, we're no longer getting bogged down in the vfs (at least at 8-way) at all. All the contention is in the actual filesystem (ext2 in group_adjust_blocks, and ext3 in the journal and block allocation code).
So again, kudos to Nick!
thanks -john
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