Hi,all
You might remember I had issues with massive swapping and wanted to know
whether I can control the amount of cache and buffers and so on.Well I
thought a mem upgrade would do the trick ,but no :-(
Not easy to explain to my boss that it still crawls with 512 MB mem and
that's the max limit in this laptop..Anyone found any solutions ?? Check
this out:
top -bn 1|head -n 30
16:25:46 up 2:56, 4 users, load average: 0.50, 0.46, 0.43
79 processes: 77 sleeping, 2 running, 0 zombie, 0 stopped
CPU states: 9.8% user, 8.5% system, 0.0% nice, 81.7% idle
Mem: 513692K total, 512072K used, 1620K free, 21564K buffers
Swap: 248968K total, 60180K used, 188788K free, 323668K cached
PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND
950 ce 14 0 150M 150M 149M R 18.2 29.9 13:01 vmware
1146 ce 17 0 1000 996 772 R 7.3 0.1 0:00 top
952 ce 9 0 42572 9528 8268 S 0.9 1.8 0:12 vmware-mks
1 root 8 0 524 480 460 S 0.0 0.0 0:03 init
2 root 9 0 0 0 0 SW 0.0 0.0 0:00 keventd
3 root 9 0 0 0 0 SW 0.0 0.0 0:00 kapm-idled
4 root 19 19 0 0 0 SWN 0.0 0.0 0:00
ksoftirqd_CPU0
5 root 9 0 0 0 0 SW 0.0 0.0 0:00 kswapd
6 root 9 0 0 0 0 SW 0.0 0.0 0:00 bdflush
7 root 9 0 0 0 0 SW 0.0 0.0 0:00 kupdated
69 root 9 0 0 0 0 SW 0.0 0.0 0:00 kreiserfsd
92 daemon 9 0 464 380 380 S 0.0 0.0 0:00 portmap
218 root 9 0 648 596 528 S 0.0 0.1 0:00 syslogd
221 root 9 0 1192 460 460 S 0.0 0.0 0:00 klogd
242 root 8 0 676 520 520 S 0.0 0.1 0:00 cardmgr
248 root 9 0 728 620 620 S 0.0 0.1 0:00 rpc.statd
251 root 8 0 512 508 496 S 0.0 0.0 0:00 apmd
262 root 9 0 556 484 484 S 0.0 0.0 0:00 inetd
307 root 9 0 1192 968 856 S 0.0 0.1 0:00 nmbd
309 root 9 0 1168 812 812 S 0.0 0.1 0:00 smbd
316 root 9 0 1240 1028 1028 S 0.0 0.2 0:00 sshd
it just caches like crazy and things start to crawl cause its
swapping.More than 300 MB of cache what on earth is being cached ?? I
can't stand ths anymore I guess I'll have to back down to 2.2 again,but
that'll have other downsides :-( *sigh*
I'm willing to help as much as I can with this I don't want to give up
on Linux just like that.
best regards
Christian
In message "swapping,any updates...", <christian e> wrote:
> Hi,all
>
> You might remember I had issues with massive swapping and wanted to know
> whether I can control the amount of cache and buffers and so on.Well I
> thought a mem upgrade would do the trick ,but no :-(
> Not easy to explain to my boss that it still crawls with 512 MB mem and
> that's the max limit in this laptop..Anyone found any solutions ?? Check
> this out:
> -snipped-
I have just wiped my LKML folder in my mail client to free up some space, so I'm
afraid I haven't read the beginning of your thread. Dunno if this will help but
I have 384MB of RAM and I _don't have_ a swap partition. Hence I don't have any
problem with swap. I've never had my machine start the OOM killer either, and I
quite often run Win2k under vmware (using 128MB of that 384), while running
Gnome/Nautilus (bloatware)/XMMS/xchat/Galeon/StarOffice (bloatware). Maybe you
push your machine harder than I do, but I've never actually needed swap on this
box... No doubt someone will tell me I'm crazy, but I'm not about to waste at
least 384*2 MB of hdd space for something that my machine doesn't seem to
need.
[You may need to tell your distro to ignore the fact you don't have any swap,
I've had to add a #Please, no swap line to the bottom of my /etc/fstab for MDK
8.1 or it continues to warn me. The damned RH installer won't let you install
without any swap (or am I missing a secret flag?).]
Joe.
+-------------------------------------------------+
| Joseph Mathewson <[email protected]> |
+-------------------------------------------------+
On Sun, 06 Jan 2002 16:31:21 +0100
christian e <[email protected]> wrote:
> Hi,all
>
> You might remember I had issues with massive swapping and wanted to know
> whether I can control the amount of cache and buffers and so on.Well I
> thought a mem upgrade would do the trick ,but no :-(
> Not easy to explain to my boss that it still crawls with 512 MB mem and
> that's the max limit in this laptop..Anyone found any solutions ?? Check
> this out:
Besides the fact I couldn't identify the kernel version from your mail, I would
try:
1) Turn off swap, then
2) Use 2.4.17 with patch I send you off LKML.
Then give us a hint if things got better.
Regards,
Stephan
christian e wrote:
> Hi,all
>
Simply try to disable swap (swapoff -a or comment out swap partitions in
/etc/fstab and reboot).
I did this on a 384 MiB SMP box as I had bad interactive performance
with some desktop apps and heavy background disk I/O (video grabing)
around 2.4.10-2.4.13 (I did not reactivate swap since) and it solved my
interactive perf woes.
You might also try Andrea's patches:
http://www.kernel.org/pub/linux/kernel/people/andrea/kernels/v2.4/2.4.17rc2aa2.bz2
or/and Rik's ones:
http://www.surriel.com/patches/2.4/2.4.17-rmap-10c
LB.
Stephan von Krawczynski wrote:
> Besides the fact I couldn't identify the kernel version from your mail, I would
> try:
>
> 1) Turn off swap, then
> 2) Use 2.4.17 with patch I send you off LKML.
>
> Then give us a hint if things got better.
Sorry forgot that.Currently running 2.4.17-mjc1.
Turning off swap is apparently not an option 'cause now VMware won't run
anymore (really a swap happy app if I ever saw one :o) I get this error
when starting to log on to my virtual Windows XP Pro:
AIO: unexpected loss of channel ide0:0 (thread ide 0:0)
and turning swap back on it runs with no problems..*sigh*
Can I make a RAM drive and then use that for swap ??Will the patch you
sent me work with swap turned on ??
For info my system:
Dell latitude cpx j650GT,650 MHz P3
512 MB mem
12 GB hdd
3com 3c575ct pcmcia NIC
Debian woody
kernel 2.4.17-mjc1
running in a dock station with Nvidia TNT2 32 MB graphic card
that should be all..
best regards
Christian
> knobs. It just won't happen. Fixing VM behavior is the only way. It has to
> work satisfactorily _without_ tuning.
Thats something you will never achieve. Virtual memory is about heuristics,
crystal ball gazing and guesswork. There are always some workloads where you
want little caching and some where you want lots of caching - such as a
fileserver.
You can make it right for most people but the last few percent you
will always get by tuning knobs - either directly or via GUI tools like
powertweak
Alan
On Mon, 7 Jan 2002, Alan Cox wrote:
> > knobs. It just won't happen. Fixing VM behavior is the only way. It has to
> > work satisfactorily _without_ tuning.
>
> Thats something you will never achieve. Virtual memory is about heuristics,
> crystal ball gazing and guesswork. There are always some workloads where you
> want little caching and some where you want lots of caching - such as a
> fileserver.
>
> You can make it right for most people but the last few percent you
> will always get by tuning knobs - either directly or via GUI tools like
> powertweak
Thank you, Alan!! Now if the *other* kernel developers would just buy
into this. :)
--
M. Edward "Give me tuning knobs or give me death" Borasky
[email protected]
http://www.borasky-research.net "The Few! The Proud! The Tweakers!"
The American people are tired of being told what the American people
are tired of.
> On Mon, 7 Jan 2002, Alan Cox wrote:
>
> > > knobs. It just won't happen. Fixing VM behavior is the only way. It has to
> > > work satisfactorily _without_ tuning.
> >
> > Thats something you will never achieve. Virtual memory is about heuristics,
> > crystal ball gazing and guesswork. There are always some workloads where you
> > want little caching and some where you want lots of caching - such as a
> > fileserver.
non sequitur: Linus would like an adaptive VM, which recognizes
apps with the properties you describe. there's no theoretical
or practical reason this cannot be achieved.
> Thank you, Alan!! Now if the *other* kernel developers would just buy
> into this. :)
you have the source. whinging about knobs is just whinging.
all serious knobs require recompilation anyway.
M. Edward (Ed) Borasky wrote:
> Thank you, Alan!! Now if the *other* kernel developers would just buy
> into this. :)
Exactly.Please think about what Alan just said.You just can't satisfy
everyone in every situation without tweaking.That's the way it is.
best regards
Christian
On January 7, 2002 05:06 pm, Alan Cox wrote:
> > knobs. It just won't happen. Fixing VM behavior is the only way. It has
> > to work satisfactorily _without_ tuning.
>
> Thats something you will never achieve. Virtual memory is about heuristics,
> crystal ball gazing and guesswork. There are always some workloads where you
> want little caching and some where you want lots of caching - such as a
> fileserver.
You can get close though. The fact that we aren't close is no proof of
impossibility. If we do give up and decide to ship only 'manual
transmissions', we can be quite sure we'll never get there.
> You can make it right for most people but the last few percent you
> will always get by tuning knobs - either directly or via GUI tools like
> powertweak
Except, as you and others have pointed out, we are far from knowing what the
knobs should be.
--
Daniel
> non sequitur: Linus would like an adaptive VM, which recognizes
> apps with the properties you describe. there's no theoretical
> or practical reason this cannot be achieved.
Oh there is. To compute the correct VM behaviour requires knowledge of
what the workload will do in the future. Now if you can solve the halting
problem and/or invent time travel I'm waiting to hear.
There are heuristics, and Linus goal is the right one. Its just useful to
recognize someone will always have a load you get wrong. Most users don't
understand tweaking vm configurations, yet even windows NT boxes let you do
so. For the critical jobs there will be someone who is willing to make the
effort to learn how to tune it.
> you have the source. whinging about knobs is just whinging.
> all serious knobs require recompilation anyway.
Now that is definitely not the case. I'm not talking
Virtual memory system (Andrea, Marcelo, Rik, Rik rmap, Linus) CONFIG_VM
On Mon, 07 Jan 2002 10:32:53 +0100
christian e <[email protected]> wrote:
> Stephan von Krawczynski wrote:
>
>
> > Besides the fact I couldn't identify the kernel version from your mail, I
would> > try:
> >
> > 1) Turn off swap, then
> > 2) Use 2.4.17 with patch I send you off LKML.
> >
> > Then give us a hint if things got better.
>
> Sorry forgot that.Currently running 2.4.17-mjc1.
Please try a stock 2.4.17 (with the patch), otherwise we will have no idea what
is going on.
> Turning off swap is apparently not an option 'cause now VMware won't run
> anymore (really a swap happy app if I ever saw one :o) I get this error
> when starting to log on to my virtual Windows XP Pro:
>
> AIO: unexpected loss of channel ide0:0 (thread ide 0:0)
>
> and turning swap back on it runs with no problems..*sigh*
Uh, this is no good. How much mem does your XP need? I can't really believe you
need more than the 512 MB you have to get this config running. Really: please
try stock kernel with patch.
> Can I make a RAM drive and then use that for swap ??Will the patch you
> sent me work with swap turned on ??
Yes, it will work of course. But we would like to see this config without swap
running too, won't we?
> For info my system:
>
> Dell latitude cpx j650GT,650 MHz P3
> 512 MB mem
> 12 GB hdd
> 3com 3c575ct pcmcia NIC
Nice box. Must work somehow.
Regards,
Stephan
On Mon, 7 Jan 2002, christian e wrote:
> M. Edward (Ed) Borasky wrote:
>
> > Thank you, Alan!! Now if the *other* kernel developers would just buy
> > into this. :)
>
> Exactly.Please think about what Alan just said.You just can't satisfy
> everyone in every situation without tweaking.That's the way it is.
There are a few things to keep in mind, however:
1) the default settings shouldn't result in any system
falling apart, it really should work everywhere
(though possibly slower than after tweaking)
2) the tunables should make sense and be easy enough
to tune without first needing to understand all of
the VM internals
regards,
Rik
--
Shortwave goes a long way: irc.starchat.net #swl
http://www.surriel.com/ http://distro.conectiva.com/
Stephan von Krawczynski wrote:
>
> Please try a stock 2.4.17 (with the patch), otherwise we will have no idea what
> is going on.
Just patched the kernel and booted it up..To begin with it looked OK and
there wasn't any swapping.Even firing up VMware didn't cause it to swap..
Then all of a sudden the mouse started moving all over the screen and
left and right clicking on everything on it's own. ?? Really weird..
Ran like that for 5 minutes then the machine crashed hard.
Now I've booted up with the std 2.4.17 again..
> Uh, this is no good. How much mem does your XP need? I can't really believe you
> need more than the 512 MB you have to get this config running. Really: please
> try stock kernel with patch.
I assigned 192 MB for XP that should be more than enough..And as long as
Linux doesn't swap it is..
> Nice box. Must work somehow.
I really hope so..*sigh* :-(
best regards
christian
On Mon, 07 Jan 2002 18:55:39 +0100
christian e <[email protected]> wrote:
> Stephan von Krawczynski wrote:
> > Please try a stock 2.4.17 (with the patch), otherwise we will have no idea
what> > is going on.
>
>
> Just patched the kernel and booted it up..To begin with it looked OK and
> there wasn't any swapping.Even firing up VMware didn't cause it to swap..
That is fine.
> Then all of a sudden the mouse started moving all over the screen and
> left and right clicking on everything on it's own. ?? Really weird..
> Ran like that for 5 minutes then the machine crashed hard.
This is for sure no VM issue. This is strange, is this with VMware started,
inside XP? Does this happen under Linux-only, too (with no vmware running)?
It doesn't even look quite like a linux issue at all. Just guessing: do you
have a virus-checker for XP at hand? Only to make sure...
> I assigned 192 MB for XP that should be more than enough..And as long as
> Linux doesn't swap it is..
This can be driven without swap for sure.
Regards,
Stephan
On 6 January 2002 13:31, christian e wrote:
> You might remember I had issues with massive swapping and wanted to know
> whether I can control the amount of cache and buffers and so on. Well I
> thought a mem upgrade would do the trick ,but no :-(
You have to face it: Linus will never accept VM subsystem with lots on tuning
knobs. It just won't happen. Fixing VM behavior is the only way. It has to
work satisfactorily _without_ tuning.
> Not easy to explain to my boss that it still crawls with 512 MB mem and
> that's the max limit in this laptop..Anyone found any solutions ?? Check
> this out:
>
> top -bn 1|head -n 30
Can you send full top output along with /proc/meminfo and /proc/slabinfo?
Last time you had mighty X (>100MB) too listed there...
> 16:25:46 up 2:56, 4 users, load average: 0.50, 0.46, 0.43
> 79 processes: 77 sleeping, 2 running, 0 zombie, 0 stopped
> CPU states: 9.8% user, 8.5% system, 0.0% nice, 81.7% idle
> Mem: 513692K total, 512072K used, 1620K free, 21564K buffers
> Swap: 248968K total, 60180K used, 188788K free, 323668K cached
>
> PID USER PRI NI SIZE RSS SHARE STAT %CPU %MEM TIME COMMAND
> 950 ce 14 0 150M 150M 149M R 18.2 29.9 13:01 vmware
> 1146 ce 17 0 1000 996 772 R 7.3 0.1 0:00 top
> 952 ce 9 0 42572 9528 8268 S 0.9 1.8 0:12 vmware-mks
Well, vmware uses binary-only kernel module, can you confirm bad behaviour
without vmware?
> it just caches like crazy and things start to crawl cause its
> swapping.More than 300 MB of cache what on earth is being cached ?? I
> can't stand ths anymore I guess I'll have to back down to 2.2 again,but
> that'll have other downsides :-( *sigh*
> I'm willing to help as much as I can with this I don't want to give up
> on Linux just like that.
You may try -aa and Rik's VM.
I'm CC'ing them, maybe they are interested...
I use a proggy below to flush caches. It triggers OOM condition. But before
it gets OOM-killed, it forces kernel to discard excessive caches. At least it
has to work that way, but it isn't (on stock kernel), which confirms your
observation that kernel is over-reluctant to flush caches.
#include <stdlib.h>
int main() {
void *p;
unsigned size = 1<<20;
unsigned long total=0;
while(size) {
p = malloc(size);
if(!p) size>>=1;
else {
memset(p, 0x77, size);
total+=size;
printf("Allocated %9u bytes, %12lu total\n",size,total);
}
}
return 0;
}
How2use:
* do repeatedly:
* top c b n 1 >topN (N=1,2,3,4,...)
* same for 'cat /proc/meminfo' and 'cat /proc/slabinfo'
* ./oom_trigger (will(should be) oom killed)
* try to figure out what cache isn't freed as it should :-)
To get clearer picture I do
* killall5 -15; sleep 3; killall5 -9 several times
first, but that will ruin your test case it seems.
Anyway, if you'll spot something unusual in those debug printouts,
please inform lkml
--
vda
[email protected] wrote:
> On 6 January 2002 13:31, christian e wrote:
> [...]
> Well, vmware uses binary-only kernel module, can you confirm bad behaviour
> without vmware?
>
VMware modules are far from GPL but they are provided with source.
Quite handy when some kernel structs change...
LB.
On Mon, 7 Jan 2002, Daniel Phillips wrote:
> On January 7, 2002 05:06 pm, Alan Cox wrote:
> > You can make it right for most people but the last few percent you
> > will always get by tuning knobs - either directly or via GUI tools like
> > powertweak
>
> Except, as you and others have pointed out, we are far from knowing what the
> knobs should be.
Hauling out my Gilbert and Sullivan: "I've got a little list" :-)
1. The time slice. Currently this is a #define. Make it a variable and
give me a sysctl to set it.
2. The processor change penalty in the scheduler. Again a #define. Make
it a variable and give me a sysctl to set it.
3. The "memory map" change penalty in the scheduler. Currently
hard-coded to 1 in "sched.c". Make it a variable and give me a sysctl to
set it.
4. The DMA, lowmem and highmem balance ratios and maxima in
"page_alloc.c". Currently these are hard coded. From the code, it looks
like the values I *really* want to change, the watermarks for each zone,
are computed at boot time and can't be changed once the system boots.
But I'd like to be able to change the watermarks at run time if at all
possible.
5. The minimum and maximum fraction of memory that can be allocated to
page cache for each zone.
--
M. Edward "Lord High Executioner" Borasky
[email protected]
http://www.borasky-research.net
http://groups.yahoo.com/group/meta-trading-coach
How to Stop A Folksinger Cold # 5
"Where have all the flowers gone..."
Beats me.
Fran?ois Cami wrote:
> try 2.4.17 with -aa patch, and then :
> echo 500 > /proc/sys/vm/vm_mapped_ratio
> tell me if it solved your problems...
>
> Cheers
>
> Fran?ois
>
I've just downloaded 2.4.18pre2 and the 2.4.18pre2aa2.So far it looks
very good.Is not even swapping yet.I'll leave it running until tomorrow
and then try and load the box some more.
best regards
Christian