Re: Performance of ext4

Holger Kiehl
2008-06-18T05:58:22Z

On Tue, 17 Jun 2008, Holger Kiehl wrote:

> Doing several test with '-m 0' I was unable to reproduce this and I could
> now do several runs with afdbench. However the results do show that with
> ext4-patch-queue it actually slower:
>
> For ext3: 5449.76 files per second 15.58 MiB/s
> For ext4: 5162.16 files per second 15.48 MiB/s
> For ext4+patch-queue: 4963.6975 files per second 14.73 MiB/s
>
> On the positive side the bonnie++ numbers got much better:
>
> Version 1.03 ------Sequential Output------ --Sequential Input-
> --Random-
> -Per Chr- --Block-- -Rewrite- -Per Chr- --Block--
> --Seeks--
> Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec
> %CP
> ext3 16G 51501 97 210601 91 100479 32 55528 98 301589 44 1198
> 5
> 16G 52702 98 215540 94 99339 32 55376 97 300933 44 1159
> 4
> 16G 52426 99 212584 94 99091 31 55656 98 301669 44 1160
> 4
> ext4 16G 52965 98 224199 89 108440 32 56389 99 303792 42 1526
> 4
> 16G 52792 98 223980 92 107685 32 56350 98 303066 42 1532
> 4
> 16G 52994 98 222354 92 107802 32 56386 99 303727 41 1455
> 4
> ext4(patchqueue)16G 59727 98 252733 52 110177 25 55821 98 296739 42 1553
> 5
> 16G 61047 99 239242 48 111664 25 55706 98 297151 42 1545
> 4
> 16G 60503 99 241532 47 109655 25 55671 98 297648 42 1552
> 3
>
> ext3 and ext4 tests where done with 2.6.25.4 and those with patch-queue was
> 2.6.26-rc5. I will do another test run with 2.6.26-rc5 without patch-queue
> just to make sure that the slowdown does not happen due to changes in the
> 2.6.26 branch.
>
Here the results without patch queue:

Version 1.03 ------Sequential Output------ --Sequential Input- --Random-
-Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP /sec %CP
16G 52133 98 221378 95 106873 32 55707 99 297065 42 1546 4
16G 52042 98 220931 93 107715 32 55939 98 298810 42 1543 3
16G 52975 98 220976 93 108060 31 56426 98 298906 42 1452 4

For afdbench: 5336.41 files per second 15.63 MiB/s

So it seems that for afdbench the ext4-patch-queue is a slowdown.

I forgot to mention that for bonnie ext4-patch-queue reduces CPU-load
a lot. For block writting it is nearly halved.

Holger