Messages in this thread | | | Subject | Re: [patch] voluntary-preempt-2.6.9-rc3-mm3-T3 | From | Lee Revell <> | Date | Wed, 13 Oct 2004 12:52:23 -0400 |
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On Tue, 2004-10-12 at 05:17, Ingo Molnar wrote: > * Lee Revell <rlrevell@joe-job.com> wrote: > > > Just to recap, these are the three problem areas that still produce > > latencies over 500 usec on my machine. > > > > journal_clean_checkpoint_list > > you might want to send this trace to Andrew too - the primary master of > ext3 latency-breaking. >
OK, Andrew, here it is. This is one of the last 2 or 3 code paths that can still produce latencies > 200 usecs on a typical machine.
--
Also, I am still seeing some long latencies in the ext3 journaling code:
preemption latency trace v1.0.7 on 2.6.9-rc3-mm3-VP-T3 ------------------------------------------------------- latency: 607 us, entries: 1087 (1087) | [VP:1 KP:1 SP:1 HP:1 #CPUS:1] ----------------- | task: kjournald/687, uid:0 nice:0 policy:0 rt_prio:0 ----------------- => started at: journal_commit_transaction+0x75/0x2830 => ended at: __journal_clean_checkpoint_list+0xb2/0xf0 =======> 00000001 0.000ms (+0.003ms): journal_commit_transaction (kjournald)
Here is the loop:
00000002 0.003ms (+0.001ms): kfree (journal_commit_transaction) 00000001 0.004ms (+0.001ms): journal_refile_buffer (journal_commit_transaction) 00000003 0.006ms (+0.000ms): __journal_refile_buffer (journal_refile_buffer) 00000003 0.006ms (+0.001ms): __journal_unfile_buffer (journal_refile_buffer) 00000002 0.008ms (+0.000ms): journal_remove_journal_head (journal_refile_buffer) 00000003 0.008ms (+0.000ms): __journal_remove_journal_head (journal_remove_journal_head) 00000003 0.009ms (+0.000ms): __brelse (__journal_remove_journal_head) 00000003 0.010ms (+0.000ms): journal_free_journal_head (journal_remove_journal_head) 00000003 0.010ms (+0.001ms): kmem_cache_free (journal_free_journal_head) 00000001 0.011ms (+0.000ms): __brelse (journal_commit_transaction)
[end loop]
00000002 0.012ms (+0.000ms): kfree (journal_commit_transaction) 00000001 0.013ms (+0.000ms): journal_refile_buffer (journal_commit_transaction)
Lee
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