Messages in this thread | | | From | Kirill Korotaev <> | Subject | Re: [PATCH] Invalidate_inodes can be very slow | Date | Mon, 13 Oct 2003 16:21:33 +0400 |
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> 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.
Kirill
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