Re: [PATCH] CFQ scheduler, #2

Mike Galbraith
2003-02-15T09:45:59Z

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At 03:19 PM 2/14/2003 +0100, Jens Axboe wrote:
>Hi,

Greetings

>The version posted the other day did fair queueing of requests between
>processes, but it did not help to provide fair request allocation. This
>version does that too, results are rather remarkable. In addition, the
>following changes were made:
>
>- Fix lost request problem with rbtree aliasing. The default io
> scheduler in 2.5.60 has the same bug, a fix has been sent separetely
> to Linus that addresses this.
>
>- Add front merging.
>
>- Missing queue_lock grab in get_request_wait() before checking request
> list count. Again, a generic kernel bug. A patch will be sent to Linus
> to address that as well.

I gave this a burn, and under hefty load it seems to provide a bit of
anti-thrash benefit.

i(dang, wish I had pine/vi for winders box)log data attached

-Mike

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2.5.61virgin make bzImage reference run
(poor box isn't _rediculously_ overloaded;)
real 8m9.710s
user 7m27.045s
sys 0m34.605s

three consecutive make -j30 bzImage runs

2.5.61cfq2
real 8m41.834s 8m36.908s 8m38.164s
user 7m37.208s 7m36.986s 7m36.456s
sys 0m42.921s 0m43.387s 0m43.312s

2.5.61virgin
real 8m39.723s 8m39.456s 8m42.102s
user 7m39.343s 7m38.800s 7m38.542s
sys 0m43.417s 0m43.322s 0m43.502s

/proc/vmstat 2.5.61cfq2 2.5.61virgin
-----------------------------------------
nr_dirty 20 13
nr_writeback 0 0
nr_pagecache 7308 7593
nr_page_table_pages 85 85
nr_reverse_maps 3229 3198
nr_mapped 599 599
nr_slab 1203 1184
pgpgin 1767432 1911614
pgpgout 1606743 1746497
pswpin 311297 338436
pswpout 371161 406675
pgalloc 3037961 3070811
pgfree 3060825 3093420
pgactivate 142329 135616
pgdeactivate 514672 507026
pgfault 4896877 4928530
pgmajfault 74342 84476
pgscan 2751953 5328260 <== ? hmm
pgrefill 1821561 1972715
pgsteal 528014 575301
pginodesteal 0 0
kswapd_steal 380282 522126
kswapd_inodesteal 7010 7132
pageoutrun 1107 1956
allocstall 3472 1238
pgrotated 358243 413450