Messages in this thread | | | Date | Sat, 21 Aug 2004 12:46:26 +0200 | From | Ingo Molnar <> | Subject | Re: [patch] voluntary-preempt-2.6.8.1-P5 |
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* Lee Revell <rlrevell@joe-job.com> wrote:
> > This one is interesting. What is going on here? > > preemption latency trace v1.0.1 > ------------------------------- > latency: 146 us, entries: 45 (45) > ----------------- > | task: pdflush/33, uid:0 nice:0 policy:0 rt_prio:0 > ----------------- > => started at: find_get_pages_tag+0x19/0x90 > => ended at: find_get_pages_tag+0x61/0x90 > =======> > 00000001 0.000ms (+0.000ms): find_get_pages_tag (pagevec_lookup_tag) > 00000001 0.000ms (+0.000ms): radix_tree_gang_lookup_tag (find_get_pages_tag) > 00000001 0.001ms (+0.000ms): __lookup_tag (radix_tree_gang_lookup_tag) > 00000001 0.007ms (+0.005ms): __lookup_tag (radix_tree_gang_lookup_tag) > > [ 20-30 more of these ]
this is the pagevec code, triggering the radix tree multi-entry-lookup code. Could you try to reduce PAGEVEC_SIZE from 16 to 8 (or 4) in include/linux/pagevec.h - does this reduce these particular latencies?
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