A SystemTap update
Posted Jan 29, 2009 10:08 UTC (Thu) by ctg (guest, #3459)
.. so reading this article was timely. Looks like systemtap would enable us to quickly home in on the big disk users..
.. the article quite clearly states that to get the best out of systemtap you need these patches, so when Mr Morton himself makes this sort of criticism, then its a bit of a concern.
Despite all that, I'm off to look at systemtap in a bit more detail (it's lack of ubiquity has put me off before), but the lack of decent tools for working out what is really going on in a complex system is pretty frustrating (I'm still suffering from the lack of the "W" flag in the output of ps(1) to show which processes are swapped out - I understand why it doesn't show that any more - but when your system goes into swap, it's useful to see which processes are being paged out.. I suspect systemtap might be able to help with this too).
Posted Jan 29, 2009 10:42 UTC (Thu) by mjw (subscriber, #16740)
Also take a look at some of the examples that come with Systemtap. disktop.stp probably does what you want:
Posted Jan 29, 2009 17:05 UTC (Thu) by knobunc (subscriber, #4678)
Posted Jan 29, 2009 20:07 UTC (Thu) by epb205 (guest, #50182)
Posted Feb 3, 2009 22:33 UTC (Tue) by oak (guest, #2786)
If the process has stuff that's marked as swapped, but not anymore as
dirty, it's completely swapped out. For some reason kernel/SMAPS doesn't
think swapped pages to be anymore dirty which loses the distinction
between shared dirty and private dirty that SMAPS shows for pages still in
Posted Jan 30, 2009 3:15 UTC (Fri) by SEJeff (subscriber, #51588)
The output looks like this:
COMMAND PID NUM ACTION DEVICE
banshee-1 23999 8 READ sda9
kjournald 2494 131 WRITE sda5
kjournald 5182 5 WRITE sda8
pdflush 228 15 WRITE sda5
pdflush 228 1 WRITE sda8
pdflush 228 32 WRITE sda9
Posted Jan 29, 2009 12:46 UTC (Thu) by eugeniy (subscriber, #24280)
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