Al Boldi wrote:
Ingo Molnar wrote:
* Al Boldi <[email protected]> wrote:
The problem is that consecutive runs don't give consistent results
and sometimes stalls. You may want to try that.
well, there's a natural saturation point after a few hundred tasks
(depending on your CPU's speed), at which point there's no idle time
left. From that point on things get slower progressively (and the
ability of the shell to start new ping tasks is impacted as well),
but that's expected on an overloaded system, isnt it?
Of course, things should get slower with higher load, but it should be
consistent without stalls.
To see this problem, make sure you boot into /bin/sh with the normal
VGA console (ie. not fb-console). Then try each loop a few times to
show different behaviour; loops like:
# for ((i=0; i<3333; i++)); do ping 10.1 -A > /dev/null & done
# for ((i=0; i<3333; i++)); do nice -99 ping 10.1 -A > /dev/null & done
# { for ((i=0; i<3333; i++)); do
ping 10.1 -A > /dev/null &
done } > /dev/null 2>&1
Especially the last one sometimes causes a complete console lock-up,
while the other two sometimes stall then surge periodically.
ok. I think i might finally have found the bug causing this. Could you
try the fix below, does your webserver thread-startup test work any
better?
It seems to help somewhat, but the problem is still visible. Even v20.3 on
2.6.22.5 didn't help.
It does look related to ia-boosting, so I turned off __update_curr like Roman
mentioned, which had an enormous smoothing effect, but then nice levels
completely break down and lockup the system.
There is another way to show the problem visually under X (vesa-driver), by
starting 3 gears simultaneously, which after laying them out side-by-side
need some settling time before smoothing out. Without __update_curr it's
absolutely smooth from the start.
I posted a LOT of stuff using the glitch1 script, and finally found a
set of tuning values which make the test script run smooth. See back
posts, I don't have them here.
--
Bill Davidsen <[email protected]>
"We have more to fear from the bungling of the incompetent than from
the machinations of the wicked." - from Slashdot
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