On Wed, 30 Sep 2015 16:35:58 +0800 "Huang\, Ying" <ying.hu...@linux.intel.com> wrote:
> Jeff Layton <jeff.lay...@primarydata.com> writes: > > > On Wed, 30 Sep 2015 07:27:54 +0800 > > "Huang\, Ying" <ying.hu...@linux.intel.com> wrote: > > > >> Jeff Layton <jeff.lay...@primarydata.com> writes: > >> > >> > On Mon, 28 Sep 2015 14:49:32 +0800 > >> > kernel test robot <ying.hu...@intel.com> wrote: > >> > > >> >> FYI, we noticed the below changes on > >> >> > >> >> ========================================================================================= > >> >> tbox_group/testcase/rootfs/kconfig/compiler/cpufreq_governor/iterations/nr_threads/disk/fs/fs2/filesize/test_size/sync_method/nr_directories/nr_files_per_directory: > >> >> > >> >> lkp-ne04/fsmark/debian-x86_64-2015-02-07.cgz/x86_64-rhel/gcc-4.9/performance/1x/32t/1HDD/xfs/nfsv4/5K/400M/fsyncBeforeClose/16d/256fpd > >> >> > >> >> commit: > >> >> cd2d35ff27c4fda9ba73b0aa84313e8e20ce4d2c > >> >> 4aac1bf05b053a201a4b392dd9a684fb2b7e6103 > >> >> > >> > > >> > A question... > >> > > >> > I think my tree should now contain a fix for this, but with a > >> > performance regression like this it's difficult to know for sure. > >> > > >> > Is there some (automated) way to request that the KTR redo this test? > >> > If not, will I get a note saying "problem seems to now be fixed" or do > >> > I just take a lack of further emails from the KTR about this as a sign > >> > that it's resolved? > >> > >> Can you provide the branch name and commit ID for your tree with fix? I > >> can confirm whether it is fixed for you. > >> > > Sure: > > > > git://git.samba.org/jlayton/linux.git nfsd-4.4 > > > > The tip commit is ed3d7c1e01a76f5ecc7444067704a82af4c2f76e. > > > > It seems that the regression is fixed at that commit. Thanks! > > ========================================================================================= > tbox_group/testcase/rootfs/kconfig/compiler/cpufreq_governor/iterations/nr_threads/disk/fs/fs2/filesize/test_size/sync_method/nr_directories/nr_files_per_directory: > > lkp-ne04/fsmark/debian-x86_64-2015-02-07.cgz/x86_64-rhel/gcc-4.9/performance/1x/32t/1HDD/xfs/nfsv4/5K/400M/fsyncBeforeClose/16d/256fpd > > commit: > cd2d35ff27c4fda9ba73b0aa84313e8e20ce4d2c > 4aac1bf05b053a201a4b392dd9a684fb2b7e6103 > ed3d7c1e01a76f5ecc7444067704a82af4c2f76e > > cd2d35ff27c4fda9 4aac1bf05b053a201a4b392dd9 ed3d7c1e01a76f5ecc74440677 > ---------------- -------------------------- -------------------------- > %stddev %change %stddev %change %stddev > \ | \ | \ > 14415356 ± 0% +2.6% 14788625 ± 1% +4.1% 15008301 ± 0% > fsmark.app_overhead > 441.60 ± 0% -2.9% 428.80 ± 0% -0.4% 439.68 ± 0% > fsmark.files_per_sec > 185.78 ± 0% +2.9% 191.26 ± 0% +0.3% 186.37 ± 0% > fsmark.time.elapsed_time > 185.78 ± 0% +2.9% 191.26 ± 0% +0.3% 186.37 ± 0% > fsmark.time.elapsed_time.max > 97472 ± 0% -2.8% 94713 ± 0% -0.8% 96657 ± 0% > fsmark.time.involuntary_context_switches > > Best Regards, > Huang, Ying Thanks for testing it and catching the problem in the first place! FWIW, the problem seems to have been bad hash distribution generated by hash_ptr on struct inode pointers. When the cache had ~10000 entries in it total, one of the hash chains had almost 2000 entries. When I switched to hashing on inode->i_ino, the distribution was much better. I'm not sure if it was just rotten luck or there is something about inode pointers that makes hash_ptr generate a lot of duplicates. That really could use more investigation... -- Jeff Layton <jeff.lay...@primarydata.com> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
