On Sun 01-08-21 09:32:40, Amir Goldstein wrote: > On Sat, Jul 31, 2021 at 10:51 PM Gabriel Krisman Bertazi > wrote: > > > > Amir Goldstein writes: > > > > > On Sat, Jul 31, 2021 at 9:20 AM kernel test robot wrote: > > >> > > >> > > >> > > >> Greeting, > > >> > > >> FYI, we noticed a -3.3% regression of unixbench.score due to commit: > > >> > > >> > > >> commit: 4c40d6efc8b22b88a45c335ffd6d25b55d769f5b ("[PATCH v4 08/16] fsnotify: pass arguments of fsnotify() in struct fsnotify_event_info") > > >> url: https://github.com/0day-ci/linux/commits/Gabriel-Krisman-Bertazi/File-system-wide-monitoring/20210721-001444 > > >> base: https://git.kernel.org/cgit/linux/kernel/git/jack/linux-fs.git fsnotify > > >> > > >> in testcase: unixbench > > >> on test machine: 96 threads 2 sockets Intel(R) Xeon(R) CPU @ 2.30GHz with 128G memory > > >> with following parameters: > > >> > > >> runtime: 300s > > >> nr_task: 1 > > >> test: pipe > > >> cpufreq_governor: performance > > >> ucode: 0x4003006 > > >> > > >> test-description: UnixBench is the original BYTE UNIX benchmark suite aims to test performance of Unix-like system. > > >> test-url: https://github.com/kdlucas/byte-unixbench > > >> > > >> In addition to that, the commit also has significant impact on the following tests: > > >> > > >> +------------------+-------------------------------------------------------------------------------------+ > > >> | testcase: change | will-it-scale: will-it-scale.per_thread_ops -1.3% regression | > > >> | test machine | 192 threads 4 sockets Intel(R) Xeon(R) Platinum 9242 CPU @ 2.30GHz with 192G memory | > > >> | test parameters | cpufreq_governor=performance | > > >> | | mode=thread | > > >> | | nr_task=100% | > > >> | | test=eventfd1 | > > >> | | ucode=0x5003006 | > > >> +------------------+-------------------------------------------------------------------------------------+ > > >> > > >> > > >> If you fix the issue, kindly add following tag > > >> Reported-by: kernel test robot > > >> > > > > > > Gabriel, > > > > > > It looks like my change throws away much of the performance gain for > > > small IO on pipes without any watches that was achieved by commit > > > 71d734103edf ("fsnotify: Rearrange fast path to minimise overhead > > > when there is no watcher"). > > > > > > I think the way to fix it is to lift the optimization in __fsnotify() > > > to the fsnotify_parent() inline wrapper as Mel considered doing > > > but was not sure it was worth the effort at the time. > > > > > > It's not completely trivial. I think it requires setting a flag > > > MNT_FSNOTIFY_WATCHED when there are watches on the > > > vfsmount. I will look into it. > > > > Amir, > > > > Since this patch is a clean up, would you mind if I drop it from my > > series and base my work on top of mainline? Eventually, we can rebase > > this patch, when the performance issue is addressed. > > > > I ask because I'm about to send a v5 and I'm not sure if I should wait > > to have this fixed. > > I guess you mean that you want to add the sb to fsnotify() args list. > I don't mind, it's up to Jan. Yeah, no problem with that from my side either. Honza -- Jan Kara SUSE Labs, CR