From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753936Ab0CYAUF (ORCPT ); Wed, 24 Mar 2010 20:20:05 -0400 Received: from smtp-out.google.com ([216.239.44.51]:25609 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751091Ab0CYAUC (ORCPT ); Wed, 24 Mar 2010 20:20:02 -0400 DomainKey-Signature: a=rsa-sha1; s=beta; d=google.com; c=nofws; q=dns; h=from:subject:to:cc:date:message-id:user-agent: mime-version:content-type:content-transfer-encoding:x-system-of-record; b=u7V3kuxTYyruFiDC9kRYIbV9NumWc9yVD7ArjRCCAwV+VjR9t+yPWeE/6xamgSbMq KH6nnPzmd2h+BVxYPeEiw== From: Divyesh Shah Subject: [PATCH] cfq-iosched: Add additional blktrace log messages in CFQ for easier debugging. To: jens.axboe@oracle.com Cc: linux-kernel@vger.kernel.org, nauman@google.com, vgoyal@redhat.com, ctalbott@google.com Date: Wed, 24 Mar 2010 17:19:34 -0700 Message-ID: <20100325001856.18289.83328.stgit@austin.mtv.corp.google.com> User-Agent: StGIT/0.14.3 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org These extra logging messages have helped us debug some issues we've noticed in earlier IO controller versions and should be useful now as well. The extra logging covers: - idling behavior. Since there are so many conditions based on which we decide to idle or not, this patch adds a log message for some conditions that we've found useful. - workload slices and current prio and workload type Signed-off-by: Divyesh Shah --- block/cfq-iosched.c | 17 +++++++++++++++-- 1 files changed, 15 insertions(+), 2 deletions(-) diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index e6910dc..556124a 100644 --- a/block/cfq-iosched.c +++ b/block/cfq-iosched.c @@ -1646,6 +1646,10 @@ static struct cfq_queue *cfq_set_active_queue(struct cfq_data *cfqd, if (!cfqq) cfqq = cfq_get_next_queue(cfqd); + if (cfqq) + cfq_log_cfqq(cfqd, cfqq, "New timeslice for wl_prio:%d " + "wl_type:%d", cfqd->serving_prio, + cfqd->serving_type); __cfq_set_active_queue(cfqd, cfqq); return cfqq; } @@ -1789,7 +1793,11 @@ static bool cfq_should_idle(struct cfq_data *cfqd, struct cfq_queue *cfqq) * Otherwise, we do only if they are the last ones * in their service tree. */ - return service_tree->count == 1 && cfq_cfqq_sync(cfqq); + if (service_tree->count == 1 && cfq_cfqq_sync(cfqq)) + return 1; + cfq_log_cfqq(cfqd, cfqq, "Not idling. queue_count:%d", + service_tree->count); + return 0; } static void cfq_arm_slice_timer(struct cfq_data *cfqd) @@ -1834,8 +1842,11 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd) * time slice. */ if (sample_valid(cic->ttime_samples) && - (cfqq->slice_end - jiffies < cic->ttime_mean)) + (cfqq->slice_end - jiffies < cic->ttime_mean)) { + cfq_log_cfqq(cfqd, cfqq, "Not idling. think_time:%d", + cic->ttime_mean); return; + } cfq_mark_cfqq_wait_request(cfqq); @@ -2043,6 +2054,7 @@ static void choose_service_tree(struct cfq_data *cfqd, struct cfq_group *cfqg) slice = max(slice, 2 * cfqd->cfq_slice_idle); slice = max_t(unsigned, slice, CFQ_MIN_TT); + cfq_log(cfqd, "workload slice:%d", slice); cfqd->workload_expires = jiffies + slice; cfqd->noidle_tree_requires_idle = false; } @@ -3309,6 +3321,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq) if (cfq_should_wait_busy(cfqd, cfqq)) { cfqq->slice_end = jiffies + cfqd->cfq_slice_idle; cfq_mark_cfqq_wait_busy(cfqq); + cfq_log_cfqq(cfqd, cfqq, "will busy wait"); } /*