Messages in this thread | | | Date | Mon, 06 Aug 2007 12:11:53 +1000 | From | Nick Piggin <> | Subject | Re: [ck] Re: -mm merge plans for 2.6.23 |
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Matthew Hawkins wrote: > On 7/25/07, Nick Piggin <nickpiggin@yahoo.com.au> wrote: > >>I guess /proc/meminfo, /proc/zoneinfo, /proc/vmstat, /proc/slabinfo >>before and after the updatedb run with the latest kernel would be a >>first step. top and vmstat output during the run wouldn't hurt either. > > > Hi Nick, > > I've attached two files with this kind of info. Being up at the cron > hours of the morning meant I got a better picture of what my system is > doing. Here's a short summary of what I saw in top: > > beagleindexer used gobs of ram. 600M or so (I have 1G)
Hmm OK, beagleindexer. I thought beagle didn't need frequent reindexing because of inotify? Oh well...
> updatedb didn't use much ram, but while it was running kswapd kept on > frequenting the top 10 cpu hogs - it would stick around for 5 seconds > or so then disappear for no more than 10 seconds, then come back > again. This behaviour persisted during the run. updatedb ran third > (beagleindexer was first, then update-dlocatedb)
Kswapd will use CPU when memory is low, even if there is no swapping.
Your "buffers" grew by 600% (from 50MB to 350MB), and slab also grew by a few thousand entries. This is not just a problem when it pushes out swap, it will also harm filebacked working set.
This (which Ray's traces also show) is a bit of a problem. As Andrew noticed, use-once isn't working well for buffer cache, and it doesn't really for dentry and inode cache either (although those don't seem to be as much of a problem on your workload).
Andrew has done a little test patch for this in -mm, but it probably wants more work and testing. If you can test the -mm kernel and see if things are improved, that would help.
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