Re: [BUG] /proc/<pid>/stat access stalls badly for swapping process, 2.4.0-test10

From: Linus Torvalds (torvalds@transmeta.com)
Date: Fri Nov 10 2000 - 12:07:48 EST


In article <Pine.Linu.4.10.10011100732250.601-100000@mikeg.weiden.de>,
Mike Galbraith <mikeg@wen-online.de> wrote:
>>
>> (This schenario, btw, is much harder to trigger on SMP than on UP. And
>> it's completely separate from the issue of simple disk bandwidth issues
>> which can obviously cause no end of stalls on anything that needs the
>> disk, and which can also happen on SMP).
>
>Unfortunately, it didn't help in the scenario I'm running.
>
>time make -j30 bzImage:
>
>real 14m19.987s (within stock variance)
>user 6m24.480s
>sys 1m12.970s

Note that the above kin of "throughput performance" should not have been
affected, and was not what I was worried about.

>procs memory swap io system cpu
> r b w swpd free buff cache si so bi bo in cs us sy id
>31 2 1 12 1432 4440 12660 0 12 27 151 202 848 89 11 0
>34 4 1 1908 2584 536 5376 248 1904 602 763 785 4094 63 32 5
>13 19 1 64140 67728 604 33784 106500 84612 43625 21683 19080 52168 28 22 50

Looks like there was a big delay in vmstat there - that could easily be
due to simple disk throughput issues..

Does it feel any different under the original load that got the original
complaint? The patch may have just been buggy and ineffective, for all I
know.

                Linus
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