Frederic Weisbecker wrote:
On Sat, Oct 10, 2009 at 01:22:16AM +0400, Michael Tokarev wrote:
Marcelo Tosatti wrote:
[snip]
Would be useful to collect sar (sar -B -b -u) output every one second
in both host/guest. You already mentioned load was low, but this should
give more details.
Here we go: http://www.corpit.ru/mjt/hrtimer-interrupt-too-slow/
Two incindents - cases when hrtimer: interrupt is too slow were
reported in the guest (with Marcelo's patch so that min_delta is
increased to 50% only), happened at 11:44:48 and 21:46:56 (as
shown in guest-dmesg file). For both, there's `sar -BWbd' output
for a 2-minute interval (starting one minute before the delay
and ending one minute after) from both host and guest.
Was there swapping going on?
Not as far as I can see, and sar output agrees.
But I can read this from you guest traces:
pgpgin/s pgpgout/s fault/s majflt/s pgfree/s pgscank/s pgscand/s pgsteal/s %vmeff
11:44:45 0.00 32.32 174.75 0.00 176.77 0.00 0.00 0.00 0.00
11:44:46 0.00 16.00 789.00 0.00 323.00 0.00 0.00 0.00 0.00
11:44:47 0.00 32.32 907.07 0.00 277.78 0.00 0.00 0.00 0.00
11:44:48 27.59 22.99 44.83 0.00 150.57 0.00 0.00 0.00 0.00
11:44:49 0.00 33.68 22.11 0.00 218.95 0.00 0.00 0.00 0.00
11:44:50 0.00 101.01 17.17 0.00 151.52 0.00 0.00 0.00 0.00
11:44:51 0.00 15.69 16.67 0.00 126.47 0.00 0.00 0.00 0.00
[...]
21:46:52 0.00 40.00 17.00 0.00 82.00 0.00 0.00 0.00 0.00
21:46:53 0.00 31.68 18.81 0.00 94.06 0.00 0.00 0.00 0.00
21:46:54 0.00 31.68 16.83 0.00 90.10 0.00 0.00 0.00 0.00
21:46:55 0.00 108.00 17.00 0.00 89.00 0.00 0.00 0.00 0.00
21:46:56 9.76 482.93 3890.24 0.00 439.02 0.00 0.00 0.00 0.00
21:46:57 0.00 760.00 8627.00 0.00 1133.00 0.00 0.00 0.00 0.00
21:46:58 0.00 84.85 2612.12 0.00 138.38 0.00 0.00 0.00 0.00
21:46:59 0.00 16.00 17.00 0.00 90.00 0.00 0.00 0.00 0.00
21:47:00 0.00 36.36 17.17 0.00 90.91 0.00 0.00 0.00 0.00
So it looks like there was some swapping in when the hrtimer (spuriously)
hanged.
It's not swapping. Swapping is in a separate table, with columns titled
pswpin/s and pswpout/s -- first table.
On my home machine with no swap at all, 4gig memory and 2gig free,
pgpgin and pgpgout are increasing too.
Also, while in the second case (21:46:56) there's actually some
noticeable activity (page faults at least), in first case that
activity is modest.
Note there's no documentation for /proc/vmstat file :)
/mjt
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