Re: unresponsiveness on linux desktop during file copy

From: Robert Hancock
Date: Sun May 17 2009 - 04:54:24 EST


Satish Eerpini wrote:
Do you believe this was working better on an earlier kernel? If so you
might drop back and see if these commands work better. If so that
would suggest a regression of some type.

I remember good performance with 2.6.26.x series, ... but I could not
try that out, ,... things on a 2.6.27.23 kernel seem no better :

Linux 2.6.27.23 (satish) 05/16/2009

12:11:18 PM CPU %user %nice %system %iowait %steal %idle
12:11:21 PM all 0.00 0.00 3.92 75.65 0.00 20.42
12:11:24 PM all 0.00 0.00 3.55 67.85 0.00 28.59
12:11:27 PM all 0.16 0.00 4.51 45.09 0.00 50.24
12:11:30 PM all 0.00 0.00 3.59 44.77 0.00 51.63
12:11:33 PM all 0.16 0.00 5.25 82.51 0.00 12.08
Average: all 0.06 0.00 4.17 63.24 0.00 32.53

the average disk speed was about 10.5 MB/s, indeed the average IOWAIT
is more than that in the latest kernel, I will see if I can test it on
a 2.6.26.x kernel or earlier one and send you guys the stats.

High iowait during a file copy with no other activity is entirely normal. If you have a core that has nothing to do but wait for IO to complete, you'll get iowait time. This isn't indicating a problem.
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