Messages in this thread | | | From | Divyesh Shah <> | Date | Mon, 12 Apr 2010 11:37:22 -0700 | Subject | Re: [PATCH] blkio: Changes to more io-controller stats patches to address |
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On Mon, Apr 12, 2010 at 7:30 AM, Vivek Goyal <vgoyal@redhat.com> wrote: > On Fri, Apr 09, 2010 at 07:35:35PM -0700, Divyesh Shah wrote: >> review comments. >> >> Changelog: (in response to Vivek Goyal's comments) >> o group blkiocg_update_blkio_group_dequeue_stats() with other DEBUG functions >> o rename blkiocg_update_set_active_queue_stats() to >> blkiocg_update_avg_queue_size_stats() >> o s/request/io/ in blkiocg_update_request_add_stats() and >> blkiocg_update_request_remove_stats() >> o Call cfq_del_timer() at request dispatch() instead of >> blkiocg_update_idle_time_stats() >> >> Signed-off-by: Divyesh Shah<dpshah@google.com> >> --- >> > > [..] >> @@ -2395,11 +2395,7 @@ static int cfq_dispatch_requests(struct request_queue *q, int force) >> } >> >> cfq_log_cfqq(cfqd, cfqq, "dispatched a request"); >> - /* >> - * This is needed since we don't exactly match the mod_timer() and >> - * del_timer() calls in CFQ. >> - */ >> - blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg); >> + cfq_del_timer(cfqd, cfqq); > > I am trying to think that why do we need this call here. What is that path > which does not delete the timer upon receiving request and lets fix that. > > One of the possible path when you got the request but still leave the > timer on is following. > > cfq_rq_enqueued() > if(request_not_big_enough) > leave_timer_on > cfq_mark_cfqq_must_dispatch(cfqq); > > I guess we need to leave timer on so that if an unplug does not come in, a > timer expirty will dispatch the request from the queue. > > In this case we can probably call here blkiocg_update_idle_time_stats() > directly. Anyway, that's the right thing to do otherwise our idle time > stats are little wrong as we got a request from the application and idle > timer is over. Now this is additional wait time enforced by cfq so that > lots of small requests are not dispatched to disk.
Good point. Will send an updated version of this patch.
> > Thanks > Vivek > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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