Messages in this thread | | | Date | Mon, 4 Aug 2003 22:02:50 -0700 | From | William Lee Irwin III <> | Subject | Re: [PATCH] O11int for interactivity |
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On Tue, 05 Aug 2003 13:38:34 +1000, Nick Piggin said: >> Of course some minimum read _latency_ would be required: this >> could actually be done easily with strace come to think of it. >> Maybe some xmms mapped memory is being swapped out? But that >> would be more of a VM problem.
On Tue, Aug 05, 2003 at 12:54:10AM -0400, Valdis.Kletnieks@vt.edu wrote: > I was seeing some CPU-related pauses, but once Con's work got to O7 or so, > those disappeared. I'm *quite* convinced that the remaining glitches > are VM related, mostly because every glitch seems to be associated with > an increase in the 'pswpout' field in /proc/vmstat (yes, I tested > with stuff like "for (;;) do cat /proc/vmstat; sleep 1 done;".
Could I get logs of the stuff?
On Tue, Aug 05, 2003 at 12:54:10AM -0400, Valdis.Kletnieks@vt.edu wrote: > The *odd* part is that the pgpgin, pgpgout, and pswpin numbers do > *NOT* seem to be correlated. High I/O loads from read/write don't > seem to cause a problem - untarring the Linux distro won't do it, > running badblocks won't do it. But if somebody has to swap out, all > hell breaks loose...
Is the swapfile/partition on the same disk as the music? Is the disk IDE?
On Tue, Aug 05, 2003 at 12:54:10AM -0400, Valdis.Kletnieks@vt.edu wrote: > Hmm.. looking at mm/page_io.c, it seems swap_writepage() calls > get_swap_bio with GFP_NOIO, while readdpage() uses GFP_KERNEL. I > wonder if that GFP_NOIO is causing ugliness - that's really > __GFP_WAIT, and the comments in bio_alloc() are pretty clear that it > can block. And remember we're not getting into this code unless > we're already under memory pressure.... > (And if somebody tells me how to instrument a -test2-mm4 kernel so I > can tell if I'm on crack or not, I'll happily do so....)
Well, sleepometer is around, but probably needs merging.
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