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authorJens Axboe <jens.axboe@oracle.com>2007-01-18 20:11:44 -0500
committerJens Axboe <axboe@carl.home.kernel.dk>2007-02-11 17:14:45 -0500
commit9ede209e83693cf3f6b64f61ab4b65f2f809cb50 (patch)
treea91ad6e7fd1b8589ecf4c8e5e027a397d89ccd6f
parent28f95cbc3ec01f2c7d248e1a4a384f37e9c2ab16 (diff)
cfq-iosched: improve continue or break logic in cfq_dispatch
This improves performance considerably for sync requests when you have command queuing enabled. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
-rw-r--r--block/cfq-iosched.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 6aa5523f514c..b6491c020f26 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1057,6 +1057,14 @@ cfq_dispatch_requests(request_queue_t *q, int force)
1057 if (prev_cfqq == cfqq) 1057 if (prev_cfqq == cfqq)
1058 break; 1058 break;
1059 1059
1060 /*
1061 * So we have dispatched before in this round, if the
1062 * next queue has idling enabled (must be sync), don't
1063 * allow it service until the previous have continued.
1064 */
1065 if (cfqd->rq_in_driver && cfq_cfqq_idle_window(cfqq))
1066 break;
1067
1060 cfq_clear_cfqq_must_dispatch(cfqq); 1068 cfq_clear_cfqq_must_dispatch(cfqq);
1061 cfq_clear_cfqq_wait_request(cfqq); 1069 cfq_clear_cfqq_wait_request(cfqq);
1062 del_timer(&cfqd->idle_slice_timer); 1070 del_timer(&cfqd->idle_slice_timer);
@@ -1066,14 +1074,6 @@ cfq_dispatch_requests(request_queue_t *q, int force)
1066 max_dispatch = 1; 1074 max_dispatch = 1;
1067 1075
1068 dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch); 1076 dispatched += __cfq_dispatch_requests(cfqd, cfqq, max_dispatch);
1069
1070 /*
1071 * If the dispatch cfqq has idling enabled and is still
1072 * the active queue, break out.
1073 */
1074 if (cfq_cfqq_idle_window(cfqq) && cfqd->active_queue)
1075 break;
1076
1077 prev_cfqq = cfqq; 1077 prev_cfqq = cfqq;
1078 } 1078 }
1079 1079