From: Zlatko Calusic <Zlatko.Calusic@CARNet.hr>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: Steve Bergman <steve@netplus.net>,
Andrea Arcangeli <andrea@e-mind.com>,
brent verner <damonbrent@earthlink.net>,
"Garst R. Reese" <reese@isn.net>,
Kalle Andersson <kalle.andersson@mbox303.swipnet.se>,
Ben McCann <bmccann@indusriver.com>,
bredelin@ucsd.edu, linux-kernel@vger.rutgers.edu,
linux-mm@kvack.org, Alan Cox <alan@lxorguk.ukuu.org.uk>,
"Stephen C. Tweedie" <sct@redhat.com>
Subject: Re: Results: 2.2.0-pre5 vs arcavm10 vs arcavm9 vs arcavm7
Date: 07 Jan 1999 19:44:18 +0100 [thread overview]
Message-ID: <87iueiudml.fsf@atlas.CARNet.hr> (raw)
In-Reply-To: Linus Torvalds's message of "Thu, 7 Jan 1999 09:35:41 -0800 (PST)"
[-- Attachment #1: Type: text/plain, Size: 4091 bytes --]
Linus Torvalds <torvalds@transmeta.com> writes:
> On Wed, 6 Jan 1999, Steve Bergman wrote:
> >
> > Here are my latest numbers. This is timing a complete kernel compile (make
> > clean;make depend;make;make modules;make modules_install) in 16MB memory with
> > netscape, kde, and various daemons running. I unknowningly had two more daemons
> > running in the background this time than last so the numbers can't be compared
> > directly with my last test (Which I think I only sent to Andrea). But all of
> > these numbers are consistent with *each other*.
> >
> >
> > kernel Time Maj pf Min pf Swaps
> > ---------- ----- ------ ------ -----
> > 2.2.0-pre5 18:19 522333 493803 27984
> > arcavm10 19:57 556299 494163 12035
> > arcavm9 19:55 553783 494444 12077
> > arcavm7 18:39 538520 493287 11526
>
> Don't look too closely at the "swaps" number - I think pre-5 just changed
> accounting a bit. A lot of the "swaps" are really just dropping a virtual
> mapping (that is later picked up again from the page cache or the swap
> cache).
>
> Basically, pre-5 uses the page cache and the swap cache more actively as a
> "victim cache", and that inflates the "swaps" number simply due to the
> accounting issues.
>
> I guess I shouldn't count the simple "drop_pte" operation as a swap at
> all, because it doesn't involve any IO.
>
2.2.0-pre5 works very good, indeed, but it still has some not
sufficiently explored nuisances:
1) Swap performance in pre-5 is much worse compared to pre-4 in
*certain* circumstances. I'm using quite stupid and unintelligent
program to check for raw swap speed (attached below). With 64 MB of
RAM I usually run it as 'hogmem 100 3' and watch for result which is
recently around 6 MB/sec. But when I lately decided to start two
instances of it like "hogmem 50 3 & hogmem 50 3 &" in pre-4 I got 2 x
2.5 MB/sec and in pre-5 it is only 2 x 1 MB/sec and disk is making
very weird and frightening sounds. My conclusion is that now (pre-5)
system behaves much poorer when we have more than one thrashing
task. *Please*, check this, it is a quite serious problem.
2) In pre-5, under heavy load, free memory is hovering around
freepages.min instead of being somewhere between freepages.low &
freepages.max. This could make trouble for bursts of atomic
allocations (networking!).
3) Nitpick #1: /proc/swapstats exist but is only filled with
zeros. Probably it should go away. I believe Stephen added it
recently, but only part of his patch got actually applied.
4) Nitpick #2": "Swap cache:" line in report of Alt-SysRq-M is not
useful as it is laid now. People have repeatedly sent patches (Rik,
Andrea...) to fix this but it is still not fixed, as of pre-5.
5) There is lots of #if 0 constructs in MM code, and also lots of
structures are not anymore used but still take precious memory in
compiled kernel and uncover itself under /proc (/proc/sys/vm/swapctl
for instance). Do you want a patch to remove this cruft?
6) Finally one suggestion of mine. In swapfile.c there is comment:
* We try to cluster swap pages by allocating them
* sequentially in swap. Once we've allocated
* SWAP_CLUSTER_MAX pages this way, however, we resort to
* first-free allocation, starting a new cluster. This
* prevents us from scattering swap pages all over the entire
* swap partition, so that we reduce overall disk seek times
This is good, but clustering of only 32 (SWAP_CLUSTER_MAX) * 4KB =
128KB is too small for today's disk and swap sizes. I tried to enlarge
this value to something like 2 MB and got much much better results.
This is very important now that we have swapin readahead to keep pages
as adjacent as possible to each other so hit rate is big. It is
trivial (one liner) and completely safe to make this constant much
bigger, so I'm not even attaching a patch. 512 works very well and
swapping is much faster than with default valuein place. Maybe this
should even be sysctl controllable. If you agree with the last idea,
I'll send you a patch, just confirm.
I promised memory hogger:
[-- Attachment #2: Hogmem.c --]
[-- Type: application/octet-stream, Size: 1067 bytes --]
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <limits.h>
#include <signal.h>
#include <time.h>
#include <sys/times.h>
#define MB (1024 * 1024)
int nr, intsize, i, t;
clock_t st;
struct tms dummy;
void intr(int intnum)
{
clock_t et = times(&dummy);
printf("\nMemory speed: %.2f MB/sec\n", (2 * t * CLK_TCK * nr + (double) i * CLK_TCK * intsize / MB) / (et - st));
exit(EXIT_SUCCESS);
}
int main(int argc, char **argv)
{
int max, nr_times, *area, c;
setbuf(stdout, 0);
signal(SIGINT, intr);
signal(SIGTERM, intr);
intsize = sizeof(int);
if (argc < 2 || argc > 3) {
fprintf(stderr, "Usage: hogmem <MB> [times]\n");
exit(EXIT_FAILURE);
}
nr = atoi(argv[1]);
if (argc == 3)
nr_times = atoi(argv[2]);
else
nr_times = INT_MAX;
area = malloc(nr * MB);
max = nr * MB / intsize;
st = times(&dummy);
for (c = 0; c < nr_times; c++)
{
for (i = 0; i < max; i++)
area[i]++;
t++;
putchar('.');
}
i = 0;
intr(0);
/* notreached */
exit(EXIT_SUCCESS);
}
[-- Attachment #3: Type: text/plain, Size: 74 bytes --]
OK, that's it for today. Don't bang heads too hard and enjoy!
--
Zlatko
next prev parent reply other threads:[~1999-01-07 18:46 UTC|newest]
Thread overview: 243+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <199812290146.BAA12687@terrorserver.swansea.linux.org.uk>
1998-12-31 18:00 ` 2.2.0 Bug summary Andrea Arcangeli
1998-12-31 18:34 ` [patch] new-vm improvement [Re: 2.2.0 Bug summary] Andrea Arcangeli
1999-01-01 0:16 ` Steve Bergman
1999-01-01 17:16 ` Andrea Arcangeli
1999-01-01 16:44 ` Andrea Arcangeli
1999-01-01 20:02 ` Andrea Arcangeli
1999-01-01 23:46 ` Steve Bergman
1999-01-02 6:55 ` Linus Torvalds
1999-01-02 8:33 ` Steve Bergman
1999-01-02 14:48 ` Andrea Arcangeli
1999-01-02 15:38 ` Andrea Arcangeli
1999-01-02 18:10 ` Linus Torvalds
1999-01-02 20:52 ` Andrea Arcangeli
1999-01-03 2:59 ` Andrea Arcangeli
1999-01-04 18:08 ` [patch] arca-vm-6, killed kswapd [Re: [patch] new-vm improvement , [Re: 2.2.0 Bug summary]] Andrea Arcangeli
1999-01-04 20:56 ` Linus Torvalds
1999-01-04 21:10 ` Rik van Riel
1999-01-04 22:04 ` Alan Cox
1999-01-04 21:55 ` Linus Torvalds
1999-01-04 22:51 ` Andrea Arcangeli
1999-01-05 0:32 ` Andrea Arcangeli
1999-01-05 0:52 ` Zlatko Calusic
1999-01-05 3:02 ` Zlatko Calusic
1999-01-05 11:49 ` Andrea Arcangeli
1999-01-05 13:23 ` Zlatko Calusic
1999-01-05 15:42 ` Andrea Arcangeli
1999-01-05 16:16 ` Zlatko Calusic
1999-01-05 15:35 ` arca-vm-8 [Re: [patch] arca-vm-6, killed kswapd [Re: [patch] new-vm , improvement , [Re: 2.2.0 Bug summary]]] Andrea Arcangeli
1999-01-06 14:48 ` Andrea Arcangeli
1999-01-06 23:31 ` Andrea Arcangeli
1999-01-07 3:32 ` Results: 2.2.0-pre5 vs arcavm10 vs arcavm9 vs arcavm7 Steve Bergman
1999-01-07 12:02 ` Andrea Arcangeli
1999-01-07 20:27 ` Linus Torvalds
1999-01-07 23:56 ` Andrea Arcangeli
1999-01-07 17:35 ` Linus Torvalds
1999-01-07 18:44 ` Zlatko Calusic [this message]
1999-01-07 19:33 ` Linus Torvalds
1999-01-07 21:10 ` Zlatko Calusic
1999-01-07 19:38 ` Zlatko Calusic
1999-01-07 19:40 ` Andrea Arcangeli
1999-01-09 6:28 ` 2.2.0-pre[56] swap performance poor with > 1 thrashing task Dax Kelson
1999-01-09 6:32 ` Zlatko Calusic
1999-01-09 6:44 ` Linus Torvalds
1999-01-09 18:58 ` Andrea Arcangeli
1999-01-11 9:21 ` Buffer handling (setting PG_referenced on access) Zlatko Calusic
1999-01-11 17:44 ` Linus Torvalds
1999-01-11 20:14 ` Zlatko Calusic
1999-01-16 17:35 ` 2.2.0-pre[56] swap performance poor with > 1 thrashing task Andrea Arcangeli
1999-01-09 7:48 ` Benjamin Redelings I
1999-01-09 6:53 ` Linus Torvalds
1999-01-09 22:39 ` Results: pre6 vs pre6+zlatko's_patch vs pre5 vs arcavm13 Steve Bergman
1999-01-10 0:28 ` Steve Bergman
1999-01-10 5:35 ` Linus Torvalds
1999-01-10 18:33 ` Andrea Arcangeli
1999-01-10 18:43 ` Steve Bergman
1999-01-10 19:08 ` Linus Torvalds
1999-01-10 19:23 ` Vladimir Dergachev
1999-01-10 20:09 ` Andrea Arcangeli
1999-01-10 20:29 ` Steve Bergman
1999-01-10 21:41 ` Linus Torvalds
1999-01-10 23:33 ` testing/pre-7 and do_poll() Chip Salzenberg
1999-01-11 6:02 ` Linus Torvalds
1999-01-11 6:26 ` Chip Salzenberg
1999-01-11 6:46 ` Linus Torvalds
1999-01-11 6:59 ` Chip Salzenberg
1999-01-11 7:02 ` Linus Torvalds
1999-01-11 22:08 ` Shawn Leas
1999-01-11 22:13 ` Linus Torvalds
1999-01-12 0:25 ` estafford
1999-01-12 8:25 ` Shawn Leas
1999-01-12 7:06 ` Gregory Maxwell
1999-01-11 20:20 ` Adam Heath
1999-01-11 16:57 ` Results: pre6 vs pre6+zlatko's_patch vs pre5 vs arcavm13 Steve Bergman
1999-01-11 19:36 ` Andrea Arcangeli
1999-01-11 23:03 ` Andrea Arcangeli
1999-01-11 23:38 ` Zlatko Calusic
1999-01-12 2:02 ` Steve Bergman
1999-01-12 3:21 ` Results: Zlatko's new vm patch Steve Bergman
1999-01-12 5:33 ` Linus Torvalds
1999-01-12 14:49 ` Andrea Arcangeli
1999-01-12 16:58 ` Joseph Anthony
1999-01-12 18:16 ` Stephen C. Tweedie
1999-01-12 20:15 ` Michael K Vance
1999-01-13 19:25 ` Stephen C. Tweedie
1999-01-12 18:24 ` Michael K Vance
1999-01-13 0:01 ` Where to find pre7. Was: " Robert Thorncrantz
1999-01-13 20:47 ` [patch] arca-vm-19 [Re: Results: Zlatko's new vm patch] Andrea Arcangeli
1999-01-14 12:30 ` Andrea Arcangeli
1999-01-15 23:56 ` [patch] NEW: arca-vm-21, swapout via shrink_mmap using PG_dirty Andrea Arcangeli
1999-01-16 16:49 ` Andrea Arcangeli
1999-01-17 23:47 ` Andrea Arcangeli
1999-01-18 5:11 ` Linus Torvalds
1999-01-18 7:28 ` Eric W. Biederman
1999-01-18 10:00 ` Andrea Arcangeli
1999-01-18 9:15 ` Andrea Arcangeli
1999-01-18 17:49 ` Linus Torvalds
1999-01-18 19:22 ` Andrea Arcangeli
1999-01-10 20:40 ` Results: pre6 vs pre6+zlatko's_patch vs pre5 vs arcavm13 Andrea Arcangeli
1999-01-10 20:50 ` Linus Torvalds
1999-01-10 21:01 ` Andrea Arcangeli
1999-01-10 21:51 ` Steve Bergman
1999-01-10 22:50 ` Results: arcavm15, et. al Steve Bergman
1999-01-11 0:20 ` Steve Bergman
1999-01-11 13:21 ` Andrea Arcangeli
1999-01-11 3:47 ` Results: pre6 vs pre6+zlatko's_patch vs pre5 vs arcavm13 Gregory Maxwell
1999-01-06 23:35 ` arca-vm-8 [Re: [patch] arca-vm-6, killed kswapd [Re: [patch] new-vm , improvement , [Re: 2.2.0 Bug summary]]] Linus Torvalds
1999-01-07 4:30 ` Eric W. Biederman
1999-01-07 17:56 ` Linus Torvalds
1999-01-07 18:18 ` Rik van Riel
1999-01-07 19:19 ` arca-vm-8 [Re: [patch] arca-vm-6, killed kswapd [Re: [patch] Alan Cox
1999-01-07 18:55 ` arca-vm-8 [Re: [patch] arca-vm-6, killed kswapd [Re: [patch] new-vm , improvement , [Re: 2.2.0 Bug summary]]] Zlatko Calusic
1999-01-07 22:57 ` Linus Torvalds
1999-01-08 1:16 ` Linus Torvalds
1999-01-08 10:45 ` Andrea Arcangeli
1999-01-08 19:06 ` Linus Torvalds
1999-01-09 9:43 ` MM deadlock [was: Re: arca-vm-8...] Savochkin Andrey Vladimirovich
1999-01-09 18:00 ` Linus Torvalds
1999-01-09 18:41 ` Andrea Arcangeli
1999-01-10 21:41 ` Stephen C. Tweedie
1999-01-10 21:47 ` Linus Torvalds
1999-01-09 21:50 ` Linus Torvalds
1999-01-10 11:56 ` Savochkin Andrey Vladimirovich
1999-01-10 17:59 ` Andrea Arcangeli
1999-01-10 22:33 ` Stephen C. Tweedie
1999-01-10 16:59 ` Stephen C. Tweedie
1999-01-10 18:13 ` Andrea Arcangeli
1999-01-10 18:35 ` Linus Torvalds
1999-01-10 19:45 ` Alan Cox
1999-01-10 19:03 ` Andrea Arcangeli
1999-01-10 21:39 ` Stephen C. Tweedie
1999-01-10 19:09 ` Linus Torvalds
1999-01-10 20:33 ` Alan Cox
1999-01-10 20:07 ` Linus Torvalds
1999-01-10 22:18 ` Stephen C. Tweedie
1999-01-10 22:49 ` Stephen C. Tweedie
1999-01-11 6:04 ` Eric W. Biederman
1999-01-12 16:06 ` Stephen C. Tweedie
1999-01-12 17:54 ` Linus Torvalds
1999-01-12 18:44 ` Zlatko Calusic
1999-01-12 19:05 ` Andrea Arcangeli
1999-01-13 17:48 ` Stephen C. Tweedie
1999-01-13 18:07 ` 2.2.0-pre6 ain't nice =( Kalle Andersson
1999-01-13 19:05 ` MM deadlock [was: Re: arca-vm-8...] Alan Cox
1999-01-13 19:23 ` MOLNAR Ingo
1999-01-13 19:26 ` Andrea Arcangeli
1999-01-14 11:02 ` Mike Jagdis
1999-01-14 22:38 ` Andrea Arcangeli
1999-01-15 7:40 ` Agus Budy Wuysang
1999-01-14 10:48 ` Mike Jagdis
1999-01-12 21:46 ` Rik van Riel
1999-01-13 6:52 ` Zlatko Calusic
1999-01-13 13:45 ` Andrea Arcangeli
1999-01-13 13:58 ` Chris Evans
1999-01-13 15:07 ` Andrea Arcangeli
1999-01-13 22:11 ` Stephen C. Tweedie
1999-01-13 14:59 ` Rik van Riel
1999-01-13 18:10 ` Andrea Arcangeli
1999-01-13 22:14 ` Stephen C. Tweedie
1999-01-14 14:53 ` Dr. Werner Fink
1999-01-21 16:50 ` Stephen C. Tweedie
1999-01-21 19:53 ` Andrea Arcangeli
1999-01-22 13:55 ` Stephen C. Tweedie
1999-01-22 19:45 ` Andrea Arcangeli
1999-01-23 23:20 ` Alan Cox
1999-01-24 0:19 ` Linus Torvalds
1999-01-24 18:33 ` Gregory Maxwell
1999-01-25 0:21 ` Linus Torvalds
1999-01-25 1:28 ` Alan Cox
1999-01-25 3:35 ` pmonta
1999-01-25 4:17 ` Linus Torvalds
1999-01-24 20:33 ` Alan Cox
1999-01-25 0:27 ` Linus Torvalds
1999-01-25 1:38 ` Alan Cox
1999-01-25 1:04 ` Andrea Arcangeli
1999-01-25 2:10 ` Alan Cox
1999-01-25 3:16 ` Garst R. Reese
1999-01-25 10:49 ` Alan Cox
1999-01-25 14:06 ` Rik van Riel
1999-01-25 21:59 ` Gerard Roudier
1999-01-26 11:45 ` Thomas Sailer
1999-01-26 20:48 ` Gerard Roudier
1999-01-26 21:24 ` Thomas Sailer
1999-01-27 0:25 ` David Lang
1999-01-27 16:05 ` Stephen C. Tweedie
1999-01-27 20:11 ` Gerard Roudier
1999-01-26 13:06 ` Stephen C. Tweedie
1999-01-26 14:28 ` Alan Cox
1999-01-26 14:15 ` MOLNAR Ingo
1999-01-26 14:36 ` yodaiken
1999-01-26 15:21 ` MOLNAR Ingo
1999-01-27 10:31 ` yodaiken
1999-01-26 15:46 ` Alan Cox
1999-01-26 16:45 ` Stephen C. Tweedie
1999-01-30 7:01 ` yodaiken
1999-02-01 13:07 ` Stephen C. Tweedie
1999-01-26 16:37 ` Stephen C. Tweedie
1999-01-27 11:35 ` Jakub Jelinek
1999-01-26 14:21 ` Rik van Riel
1999-01-25 16:25 ` Stephen C. Tweedie
1999-01-25 16:52 ` Andrea Arcangeli
1999-01-25 18:27 ` Linus Torvalds
1999-01-25 18:43 ` Stephen C. Tweedie
1999-01-25 18:49 ` Linus Torvalds
1999-01-25 18:43 ` Linus Torvalds
1999-01-25 19:15 ` Stephen C. Tweedie
1999-01-26 1:57 ` Andrea Arcangeli
1999-01-26 18:37 ` Andrea Arcangeli
1999-01-27 12:13 ` Stephen C. Tweedie
1999-01-22 16:29 ` Eric W. Biederman
1999-01-25 13:14 ` Dr. Werner Fink
1999-01-25 17:56 ` Stephen C. Tweedie
1999-01-25 19:10 ` Andrea Arcangeli
1999-01-25 20:49 ` Dr. Werner Fink
1999-01-25 20:56 ` Linus Torvalds
1999-01-26 12:23 ` Rik van Riel
1999-01-26 15:44 ` Andrea Arcangeli
1999-01-27 14:52 ` Stephen C. Tweedie
1999-01-28 19:12 ` Dr. Werner Fink
1999-01-13 17:55 ` [PATCH] " Stephen C. Tweedie
1999-01-13 18:52 ` Andrea Arcangeli
1999-01-13 22:10 ` Stephen C. Tweedie
1999-01-13 22:30 ` Linus Torvalds
1999-01-11 11:20 ` Pavel Machek
1999-01-11 17:35 ` Stephen C. Tweedie
1999-01-11 14:11 ` Savochkin Andrey Vladimirovich
1999-01-11 17:55 ` Linus Torvalds
1999-01-11 18:37 ` Andrea Arcangeli
1999-01-08 2:56 ` arca-vm-8 [Re: [patch] arca-vm-6, killed kswapd [Re: [patch] new-vm , improvement , [Re: 2.2.0 Bug summary]]] Eric W. Biederman
1999-01-09 0:50 ` David S. Miller
1999-01-09 2:13 ` Stephen C. Tweedie
1999-01-09 2:34 ` Andrea Arcangeli
1999-01-09 9:30 ` Stephen C. Tweedie
1999-01-09 12:11 ` Andrea Arcangeli
1999-01-07 14:11 ` Andrea Arcangeli
1999-01-07 18:19 ` Linus Torvalds
1999-01-07 20:35 ` Andrea Arcangeli
1999-01-07 23:51 ` Linus Torvalds
1999-01-08 0:04 ` Andrea Arcangeli
1999-01-04 22:43 ` [patch] arca-vm-6, killed kswapd [Re: [patch] new-vm improvement , [Re: 2.2.0 Bug summary]] Andrea Arcangeli
1999-01-04 22:29 ` Andrea Arcangeli
1999-01-05 13:33 ` [patch] new-vm improvement [Re: 2.2.0 Bug summary] Ben McCann
1999-01-02 20:04 ` Steve Bergman
1999-01-02 3:03 ` Andrea Arcangeli
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