Hi'all,
Anyone remember this thread:
"severe slowdown with 2.4 series w/heavy disk access"
http://hypermail.spyroid.com/linux-kernel/archived/2001/week52/0266.html
It describes the tendency of 2.4 series kernels to slowdown under I/O load.
Well, that problem still seems to be alive and kicking. And no, it is not
related to reiserfs as I previously suggested in this thread:
"Abysmal interactive performance on 2.4.linus", archived here:
http://www.uwsg.iu.edu/hypermail/linux/kernel/0111.1/0911.html
I removed the last reiserfs partition quite some time ago, currently running
mostly ext3 with ext2 root fs.
The systems use IDE disks, I don't have any SCSI-systems handy to test whether
this might be IDE-only (anyone?). Currently running 2.4.18 (with preempt and
lowlatency, but the problems are NOT related to those patches as they also hit
unpatched kernels) on SMP (Abit BP-6 yeah yeah I know but it does not seem to
be specific to the BP-6).
Does anyone else see these problems? Specifically, does anyone with a
SCSI-based system see this happening? Also, does anyone who uses only ext2 (no
ext3 or reiserfs, let alone jfs/xfs or any other journaling fs) see this?
Cheers//Frank
[ BTW: I'm moving to Sweden, and am looking for a project/job in V?stra
G?taland, preferrably G?teborg... Anyone know anything interesting? ]
--
WWWWW ________________________
## o o\ / Frank de Lange \
}# \| / \
\ `--| _/ <Hacker for Hire> \
`---' \ /
\ [email protected] /
`------------------------'
[ "Omnis enim res, quae dando non deficit, dum habetur
et non datur, nondum habetur, quomodo habenda est." ]
To clear up some potential confusion, the problems I'm talking about are NOT
related to the (erroneous) memory-related questions in the thread I pointed at.
It is the slowdowns which bother me, not the fact that the system 'uses up all
memory' (which is a good thing (tm)). Read a bit further into the thread and
you'll end up here:
http://hypermail.spyroid.com/linux-kernel/archived/2001/week52/0309.html
quote Alan Cox: "The free behaviour is correct (free memory is wasted memory).
The delays are obviously not"
That's why I'm asking these questions. The delays should not be there, but they
are, reproducible, over many different kernels and with several filesystems.
Cheers//Frank
[ Moving to Sweden, looking for a project/job in V?stra G?taland... ]
--
WWWWW ________________________
## o o\ / Frank de Lange \
}# \| / \
\ `--| _/ <Hacker for Hire> \
`---' \ +31-320-252965 /
\ [email protected] /
`------------------------'
[ "Omnis enim res, quae dando non deficit, dum habetur
et non datur, nondum habetur, quomodo habenda est." ]
Hi Frank,
>Hi'all,
>Anyone remember this thread:
> "severe slowdown with 2.4 series w/heavy disk access"
>http://hypermail.spyroid.com/linux-kernel/archived/2001/week52/0266.html
>It describes the tendency of 2.4 series kernels to slowdown under I/O
>load.
[..snip..]
I tried copying a 650MB file to the same file system on an IDE disk
and...
(This is while the copy is running)
$ time ls -l
total 1284548
-rw-r--r-- 1 shane shane 685183312 Apr 19 18:13 650MB_tar_ball
-rw-r--r-- 1 shane shane 628895744 Apr 19 18:44 X
0.00user 0.00system 0:00.00elapsed 0%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (191major+35minor)pagefaults 0swaps
$ time ls -l
total 1287624
-rw-r--r-- 1 shane shane 685183312 Apr 19 18:13 650MB_tar_ball
-rw-r--r-- 1 shane shane 632041472 Apr 19 18:44 X
0.01user 0.00system 0:00.00elapsed 500%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (191major+35minor)pagefaults 0swaps
$ time ls -l
total 1290188
-rw-r--r-- 1 shane shane 685183312 Apr 19 18:13 650MB_tar_ball
-rw-r--r-- 1 shane shane 634662912 Apr 19 18:44 X
0.01user 0.00system 0:00.00elapsed 500%CPU (0avgtext+0avgdata
0maxresident)k
0inputs+0outputs (191major+35minor)pagefaults 0swaps
vmstat 1 was running as well
procs memory swap io system cpu
r w b swpd free buf cache si so bi bo in cs us sy id
0 0 0 53580 12296 3008 258120 0 0 0 0 180 87 0 0 100
1 0 0 53580 12296 3008 258120 0 0 0 0 176 67 0 0 100
3 0 0 53580 120492 3008 149836 0 0 2316 0 240 232 1 13 86
2 0 0 53580 59432 3008 210596 0 0 30208 0 852 1491 3 42 55
0 1 0 53580 4740 3012 264864 0 0 30212 0 652 1107 1 39 60
0 1 1 53580 4600 3012 264696 0 0 23048 5760 586 885 2 31 67
1 1 2 53580 4492 3016 264784 0 0 2560 17540 504 207 0 7 93
0 1 1 53580 4324 3016 264944 0 0 2560 18304 501 256 0 6 94
0 1 1 53580 4284 3016 264968 0 0 2048 16128 509 244 0 6 94
0 1 1 53580 4488 3016 264740 0 0 2048 18020 499 206 0 5 95
1 0 0 53604 4216 3028 266368 0 0 9732 10192 539 438 0 18 82
0 1 1 53604 4424 3028 266056 0 0 6144 18148 525 395 2 6 92
1 0 0 53604 3924 2904 266860 0 6019968 3900 614 866 0 35 65
1 0 0 53604 4668 2908 265728 0 0 29188 0 634 1077 0 39 61
...
This is on a UP AMD Tbird, 384MB, on an IDE disk on a Promise TX133
controller. The Gnome desktop was responsive throughout the copy.
This is with the 2.4.19-pre6aa1 kernel. Give it a try...if you want.
Regards,
Shane