Re: 2.6.0 performance problems

[Jens Axboe <axboe@suse.de>]

On Fri, Jan 02 2004, Roger Luethi wrote:
> On Wed, 31 Dec 2003 12:21:19 +0100, Jens Axboe wrote:
> > the qsbench suckiness? Do you have numbers for 2.4.x and 2.6.1-rc with
> > the various io schedulers (it would be interesting to see stock,
> > elevator=deadline, and elevator=noop).
> 
> For 2.6 AS comes out on top. It seems though that AS may be at least
> partially responsible for the exploding variance of run times for
> qsbench.
> 
> I don't think we can compare 2.4 and 2.6 I/O schedulers for these
> loads. The io scheduler can do only so much if the VM evicts the
> wrong pages.

Agree, in case of a thrashing vm it's an impossible job.

> Average, times for ten runs (in seconds, ordered).
> 
> efax		avg
> 2.4.23		228.8 227 227 228 229 229 229 229 230 230 230
> 2.6.0 noop	861.8 833 855 860 865 866 866 867 867 869 870
> 2.6.0 deadline	846.1 813 827 830 845 850 854 856 859 861 866
> 2.6.0 as	850.8 827 834 839 840 840 841 864 864 874 885
> 
> kbuild		avg
> 2.4.23		140.4 116 118 124 125 132 150 153 157 161 168
> 2.6.0 noop	638.2 552 569 596 600 608 631 634 658 712 822
> 2.6.0 deadline	570.0 494 495 517 529 532 545 596 619 670 703
> 2.6.0 as	486.1 406 429 453 468 473 477 510 536 542 567
> 
> qsbench		avg
> 2.4.23		223.8 219 220 221 223 223 223 223 225 230 231
> 2.6.0 noop	380.0 333 343 374 377 382 389 391 391 403 417
> 2.6.0 deadline	368.8 339 361 361 372 372 373 375 377 377 381
> 2.6.0 as	329.3 253 279 281 286 300 355 371 374 388 406

-- 
Jens Axboe