Messages in this thread | ![/](/images/icornerl.gif) | | From | Nikita Danilov <> | Date | Mon, 13 Oct 2003 16:29:04 +0400 | Subject | Re: [PATCH] Invalidate_inodes can be very slow |
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Kirill Korotaev writes: > > At some point in the past, I wrote: > > >> Sorry if I was unclear, I had in mind SMP performance testing of mount > > >> and unmount -heavy workloads, like uni setups with many automounted > > >> fs's, not stability testing per se. > > > > On Mon, Oct 13, 2003 at 04:02:20PM +0400, Kirill Korotaev wrote: > > > Oh, sorry for misunderstanding. > > > In our internal testcase on 8-CPU 8Gb RAM machine with 4gb split kernel > > > w/o this patch mount/umount test longs in many-many (>10) times longer. > > > Moreover, during the test machine is very slow (due to lock_kernel) > > > and typing simple commands takes up to 30 seconds or so. > > > I think such a long hangs are due to number of umounts executed > > > subsequently. But ofcourse it's not numbers, just for you to know where > > > the patch comes from :) > > > > Is this testcase available and/or trivial? Actually, even if it's trivial > > it might just save us the pain of writing the scripts ourselves. > no, testcase is not available :( And it uses functionality > not available in mainstream kernel. But the problem can be hit with > very simple script instead: > > 1. mount N filesystems. > 2. work on them, so that inode cache grows to its maximum > possible size (it was 1,000,000 of inodes in our case). > 3. umount these filesystems. > > During operation #3 node is very slow and it is quite noticable > on ssh console when typing commands.
This can be due to a number of reasons (worst case behavior of shrink_dcache_parent() for example). What /proc/profile shows?
> > Kirill
Nikita.
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