Re: Time sliced CFQ io scheduler

Prakash K. Cheemplavam
2004-12-03T09:54:25Z

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Jens Axboe schrieb:
> On Fri, Dec 03 2004, Andrew Morton wrote:
>
>>Is this a parallel IDE system? SATA? SCSI? If the latter, what driver
>>and what is the TCQ depth?
>
>
> Yeah, that would be interesting to know. Or of the device is on dm or
> raid. And what filesystem is being used?

It is ext3. (The writing-makes-reading-starve problem happen on reiserfs
as well. ext2 is not so bad and xfs behaves best, ie my email client
doesn't get unuasable with my earlier tests, but "only" very slow. But
then I only wrote down 2gb and nothing continuesly.)

> # cd /sys/block/<dev>/queue/iosched
> # echo 6 > idle
> # echo 150 > slice
>
> These are the first I tried, there may be better settings. If you have
> your filesystem on dm/raid, you probably want to do the above for each
> device the dm/raid is composed of.

Yes, I have linux raid (testing md1). Have appield both settings on both
drives and got a interesting new pattern: Now it alternates. My email
client is still not usale while writing though...

0 3 4120 5276 1792 856784 0 0 3880 81372 1528 931 1 17
0 82
0 4 4120 5576 1800 856148 0 0 1292 121136 1379 872 5
12 0 83
0 3 4120 6624 1796 857700 0 0 1548 4464 1324 712 4 7
0 89
1 3 4120 5200 1568 859600 0 0 42608 2308 1679 1392 3
28 0 69
1 3 4120 5212 1472 856672 0 0 12372 94992 1451 1047 1
30 0 69
1 2 4120 5700 1476 856892 0 0 2576 27252 1337 770 2 9
0 89
0 3 4120 5404 1484 860292 0 0 2076 63876 1323 758 2
13 0 85
procs -----------memory---------- ---swap-- -----io---- --system--
----cpu----
r b swpd free buff cache si so bi bo in cs us
sy id wa
1 2 4120 5536 1492 860240 0 0 49248 12 1783 1478 2
26 0 72
0 3 4120 5476 1492 857976 0 0 21852 98552 1500 1021 2
20 0 78
0 3 4120 5340 1552 860104 0 0 2672 36920 1321 717 1
15 0 84
0 4 4120 5436 1588 861080 0 0 2364 20748 1331 716 1
12 0 87
0 3 4120 5092 1632 860012 0 0 59520 0 1810 1591 3
32 0 65
0 3 4120 5568 1616 858252 0 0 58232 0 1833 1519 2
30 0 68
0 2 4120 5508 1548 857784 0 0 3864 70500 1347 767 1
13 0 86
0 2 4120 5376 1488 857760 0 0 5164 41440 1317 800 2
15 0 83
0 3 4120 5256 1484 858448 0 0 6452 111292 1342 829 2
22 0 76
0 3 4120 5832 1488 858768 0 0 2060 26624 1320 769 2 5
0 93
3 4 4120 5564 1492 859644 0 0 20568 12 1426 1048 1
25 0 75
0 2 4120 5448 1516 857548 0 0 41056 47636 1746 1355 2
29 0 69
0 2 4120 5572 1524 858020 0 0 2332 25020 1330 737 1
10 0 89
0 3 4120 5508 1568 858020 0 0 4152 130164 1338 844 2
20 0 78
1 3 4120 6260 1588 858840 0 0 836 14288 1314 747 1 3
0 96
1 3 4120 5192 1644 860304 0 0 41628 12 1677 2226 2
31 0 67
2 3 4120 5308 1588 857448 0 0 53324 1456 2044 9456 2
60 0 38

Prakash

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