Messages in this thread Patch in this message | | | Date | Sat, 21 Feb 2004 09:40:41 +1100 | From | Nick Piggin <> | Subject | Re: High read Latency test (Anticipatory I/O scheduler) |
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John Chatelle wrote:
> I haven't seen much duplicated results regarding the Robert Love article >in the February 2004 Linux Journal article, also reachable in the hyperlink: > http://www.linuxjournal.com/article.php?sid=6931 > > Although the 1st simple test: "Write starved reads" gets results comparable >to the results reported in the Article, Our results for the 2nd test: "High >Read latency" delivers results opposite our expectations... > >
Hi John, Can you try the following patch please? If that doesn't help, can you show me what /sys/block/hda/queue/iosched/est_time says after your test has been running for a couple of minutes.
Thanks Nick
linux-2.6-npiggin/drivers/block/as-iosched.c | 2 ++ 1 files changed, 2 insertions(+)
diff -puN drivers/block/as-iosched.c~as-exit-prob drivers/block/as-iosched.c --- linux-2.6/drivers/block/as-iosched.c~as-exit-prob 2004-02-21 09:38:54.000000000 +1100 +++ linux-2.6-npiggin/drivers/block/as-iosched.c 2004-02-21 09:39:22.000000000 +1100 @@ -734,8 +734,10 @@ static int as_can_break_anticipation(str if (aic->ttime_samples == 0) { if (ad->new_ttime_mean > ad->antic_expire) return 1; +#if 0 if (ad->exit_prob > 128) return 1; +#endif } else if (aic->ttime_mean > ad->antic_expire) { /* the process thinks too much between requests */ return 1; _
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