Trying out 2.6.0-test4-mm1. Inside KDE, I start OpenOffice.org, Rational Rose and Konsole at a time. All of these take extremely long time to startup. (approx > 5 minutes). Kswapd hogs the CPU all the time.
X becomes unusable till all of them startup, although I can telnet and run top.
Same thing run under 2.4.18 starts up in 3 minutes, X stays usable and kswapd never take more than 2% CPU.
Here a snapshot of Top output when running 2.6.0-test4-mm1:
==============================
4:24pm up 21:19, 6 users, load average: 3.47, 2.04, 1.49
96 processes: 88 sleeping, 8 running, 0 zombie, 0 stopped
CPU states: 11.3% user, 88.6% system, 0.0% nice, 0.0% idle
Mem: 124632K av, 122664K used, 1968K free, 0K shrd, 160K buff
Swap: 1052248K av, 71256K used, 980992K free 43540K cached
PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND
8 root 15 0 0 0 0 SW 66.6 0.0 4:59 kswapd0
2087 wipro 17 0 29576 10M 27408 S 4.6 8.9 0:03 kdeinit
2044 wipro 17 0 118M 22M 103M D 2.7 18.8 0:04 soffice.bin
2292 wipro 18 0 3856 912 3716 S 1.8 0.7 0:02 top
2312 wipro 18 0 3852 912 3716 R 1.8 0.7 0:00 top
540 wipro 15 0 28988 6640 26672 S 0.9 5.3 10:40 kdeinit
1254 wipro 15 0 26340 4916 24716 S 0.9 3.9 0:17 kdeinit
1 root 17 0 1320 268 1288 S 0.0 0.2 0:04 init
2 root 0K 0 0 0 0 SW 0.0 0.0 0:00 migration/0
3 root 34 19 0 0 0 SWN 0.0 0.0 0:00 ksoftirqd/0
4 root 5 -10 0 0 0 SW< 0.0 0.0 0:00 events/0
5 root 5 -10 0 0 0 SW< 0.0 0.0 0:01 kblockd/0
6 root 15 0 0 0 0 SW 0.0 0.0 0:00 pdflush
7 root 15 0 0 0 0 SW 0.0 0.0 0:00 pdflush
9 root 10 -10 0 0 0 SW< 0.0 0.0 0:00 aio/0
10 root 10 -10 0 0 0 SW< 0.0 0.0 0:00 aio_fput/0
11 root 15 0 0 0 0 SW 0.0 0.0 0:00 kseriod
12 root 15 0 0 0 0 SW 0.0 0.0 0:00 kjournald
On Wed, Aug 27, 2003 at 04:38:44PM -0500, [email protected] wrote:
> Here a snapshot of Top output when running 2.6.0-test4-mm1:
> ==============================
> 4:24pm up 21:19, 6 users, load average: 3.47, 2.04, 1.49
> 96 processes: 88 sleeping, 8 running, 0 zombie, 0 stopped
> CPU states: 11.3% user, 88.6% system, 0.0% nice, 0.0% idle
> Mem: 124632K av, 122664K used, 1968K free, 0K shrd, 160K buff
> Swap: 1052248K av, 71256K used, 980992K free 43540K cached
>
> PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND
> 8 root 15 0 0 0 0 SW 66.6 0.0 4:59 kswapd0
> 2087 wipro 17 0 29576 10M 27408 S 4.6 8.9 0:03 kdeinit
> 2044 wipro 17 0 118M 22M 103M D 2.7 18.8 0:04 soffice.bin
This looks odd. At any rate, the 71MB swap should be a big hint you're
in for slow times. 2.4.x likely does okay here because the virtualscan
acts as implicit load control; 2.6.x will likely need explicit load
control to handle that workload on that machine.
-- wli
On Wed, Aug 27, 2003 at 04:38:44PM -0500, [email protected] wrote:
> Trying out 2.6.0-test4-mm1. Inside KDE, I start OpenOffice.org,
> Rational Rose and Konsole at a time. All of these take extremely long
> time to startup. (approx > 5 minutes). Kswapd hogs the CPU all the time.
> X becomes unusable till all of them startup, although I can telnet
> and run top. Same thing run under 2.4.18 starts up in 3 minutes, X
> stays usable and kswapd never take more than 2% CPU.
Also, can you capture vmstat 1 with this?
-- wli
On Thu, 28 Aug 2003 07:38, [email protected] wrote:
> Trying out 2.6.0-test4-mm1. Inside KDE, I start OpenOffice.org, Rational
> Rose and Konsole at a time. All of these take extremely long time to
> startup. (approx > 5 minutes). Kswapd hogs the CPU all the time. X becomes
> unusable till all of them startup, although I can telnet and run top. Same
> thing run under 2.4.18 starts up in 3 minutes, X stays usable and kswapd
> never take more than 2% CPU.
Yes I can reproduce this with a memory heavy load as well on low memory
(linking at the end of a big kernel compile is standard problem). I actually
found the best workaround was to increase the swappiness instead of
decreasing it.
Try
echo 100 > /proc/sys/vm/swappiness
time it
then try
echo 0 > /proc/sys/vm/swappiness
you'll see that at low swappiness kswapd0 can use ridiculous amounts of cpu
trying to avoid swap. The default is 60.
Con
On Wednesday, 27 August 2003, at 16:38:44 -0500,
[email protected] wrote:
> Same thing run under 2.4.18 starts up in 3 minutes, X stays usable and kswapd never take more than 2% CPU.
>
OpenOffice is know to have severe performance problems with kernels
2.5.x and 2.6.x kernels in the presence of any CPU hog in the box. It is
a known problem that seems to have been corrected in OO 1.1.0-RC3. Note
I am talking about the symptom, not about the cause of your overall
system slowness.
Regards,
--
Jose Luis Domingo Lopez
Linux Registered User #189436 Debian Linux Sid (Linux 2.6.0-test4-mm1)
Con - With swappiness set to 100, the apps do start up in 3 minutes and kswapd doesn't hog the CPU. But X is still unusable till all of them have started up.
Wli - Sorry, vmstat segfaults on 2.6!
[email protected] wrote
On Thu, 28 Aug 2003 07:38, [email protected] wrote:
> Trying out 2.6.0-test4-mm1. Inside KDE, I start OpenOffice.org, Rational
> Rose and Konsole at a time. All of these take extremely long time to
> startup. (approx > 5 minutes). Kswapd hogs the CPU all the time. X becomes
> unusable till all of them startup, although I can telnet and run top. Same
> thing run under 2.4.18 starts up in 3 minutes, X stays usable and kswapd
> never take more than 2% CPU.
Yes I can reproduce this with a memory heavy load as well on low memory
(linking at the end of a big kernel compile is standard problem). I actually
found the best workaround was to increase the swappiness instead of
decreasing it.
Try
echo 100 > /proc/sys/vm/swappiness
time it
then try
echo 0 > /proc/sys/vm/swappiness
you'll see that at low swappiness kswapd0 can use ridiculous amounts of cpu
trying to avoid swap. The default is 60.
Con
Con Kolivas <[email protected]> wrote:
>
> On Thu, 28 Aug 2003 07:38, [email protected] wrote:
> > Trying out 2.6.0-test4-mm1. Inside KDE, I start OpenOffice.org, Rational
> > Rose and Konsole at a time. All of these take extremely long time to
> > startup. (approx > 5 minutes). Kswapd hogs the CPU all the time. X becomes
> > unusable till all of them startup, although I can telnet and run top. Same
> > thing run under 2.4.18 starts up in 3 minutes, X stays usable and kswapd
> > never take more than 2% CPU.
>
> Yes I can reproduce this with a memory heavy load as well on low memory
> (linking at the end of a big kernel compile is standard problem).
It could be that recent changes to page reclaim which improve I/O
scheduling have exacerbated this.
Does this make a difference?
diff -puN mm/vmscan.c~a mm/vmscan.c
--- 25/mm/vmscan.c~a Wed Aug 27 12:51:36 2003
+++ 25-akpm/mm/vmscan.c Wed Aug 27 12:51:48 2003
@@ -360,8 +360,6 @@ shrink_list(struct list_head *page_list,
* See swapfile.c:page_queue_congested().
*/
if (PageDirty(page)) {
- if (referenced)
- goto keep_locked;
if (!is_page_cache_freeable(page))
goto keep_locked;
if (!mapping)
_
On Thu, 28 Aug 2003 05:53, Andrew Morton wrote:
> Con Kolivas <[email protected]> wrote:
> > On Thu, 28 Aug 2003 07:38, [email protected] wrote:
> > > Trying out 2.6.0-test4-mm1. Inside KDE, I start OpenOffice.org,
> > > Rational Rose and Konsole at a time. All of these take extremely long
> > > time to startup. (approx > 5 minutes). Kswapd hogs the CPU all the
> > > time. X becomes unusable till all of them startup, although I can
> > > telnet and run top. Same thing run under 2.4.18 starts up in 3 minutes,
> > > X stays usable and kswapd never take more than 2% CPU.
> >
> > Yes I can reproduce this with a memory heavy load as well on low memory
> > (linking at the end of a big kernel compile is standard problem).
>
> It could be that recent changes to page reclaim which improve I/O
> scheduling have exacerbated this.
>
> Does this make a difference?
Tried it. No change.
kswapd0 can hit 90% cpu at times unless the swappiness is increased.
Con
I faced a similar problem with 2.6.0-test4-mm2 while using unstable kde
3.1.9x(?)
In fact I was not able to do anything and my system became unresponsive,
with kswapd0
hogging 60% CPU. Later X got killed ... I did not face such a situation in
any of the previous
releases (I have been using 2.5 since 2.5.70 )
[ I have 256 MB RAM and 256 SWAP with P4 2.0 GHz]
Tariq Firoz
----- Original Message -----
From: "Andrew Morton" <[email protected]>
To: "Con Kolivas" <[email protected]>
Cc: <[email protected]>; <[email protected]>
Sent: Thursday, August 28, 2003 1:23 AM
Subject: Re: 2.6.0-test4-mm1 - kswap hogs cpu OO takes ages to start!
> Con Kolivas <[email protected]> wrote:
> >
> > On Thu, 28 Aug 2003 07:38, [email protected] wrote:
> > > Trying out 2.6.0-test4-mm1. Inside KDE, I start OpenOffice.org,
Rational
> > > Rose and Konsole at a time. All of these take extremely long time to
> > > startup. (approx > 5 minutes). Kswapd hogs the CPU all the time. X
becomes
> > > unusable till all of them startup, although I can telnet and run top.
Same
> > > thing run under 2.4.18 starts up in 3 minutes, X stays usable and
kswapd
> > > never take more than 2% CPU.
> >
> > Yes I can reproduce this with a memory heavy load as well on low memory
> > (linking at the end of a big kernel compile is standard problem).
>
> It could be that recent changes to page reclaim which improve I/O
> scheduling have exacerbated this.
>
> Does this make a difference?
>
> diff -puN mm/vmscan.c~a mm/vmscan.c
> --- 25/mm/vmscan.c~a Wed Aug 27 12:51:36 2003
> +++ 25-akpm/mm/vmscan.c Wed Aug 27 12:51:48 2003
> @@ -360,8 +360,6 @@ shrink_list(struct list_head *page_list,
> * See swapfile.c:page_queue_congested().
> */
> if (PageDirty(page)) {
> - if (referenced)
> - goto keep_locked;
> if (!is_page_cache_freeable(page))
> goto keep_locked;
> if (!mapping)
>
> _
>
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to [email protected]
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>
On Thu, 28 Aug 2003, Con Kolivas wrote:
> > Does this make a difference?
>
> Tried it. No change.
>
> kswapd0 can hit 90% cpu at times unless the swappiness is increased.
Looks like the problem is that cache and process pages are on
the same lists, forcing kswapd to scan the lists endlessly.
One thing you could try is splitting the lists, at least the
active list, like done in 2.4-rmap15...
--
"Debugging is twice as hard as writing the code in the first place.
Therefore, if you write the code as cleverly as possible, you are,
by definition, not smart enough to debug it." - Brian W. Kernighan
But eventually, kswapd does stop scanning and machine is back to normal after a 2 min freeze.
BTW, how is it cured at swappiness ==100?
>
>
> On Thu, 28 Aug 2003, Con Kolivas wrote:
>
> > > Does this make a difference?
> >
> > Tried it. No change.
> >
> > kswapd0 can hit 90% cpu at times unless the swappiness is increased.
>
> Looks like the problem is that cache and process pages are on
> the same lists, forcing kswapd to scan the lists endlessly.
>
> One thing you could try is splitting the lists, at least the
> active list, like done in 2.4-rmap15...
>
> --
> "Debugging is twice as hard as writing the code in the first place.
> Therefore, if you write the code as cleverly as possible, you are,
> by definition, not smart enough to debug it." - Brian W. Kernighan
>