Messages in this thread | | | Subject | [PATCH v2 0/3]CFQ: add think time check for service tree and group | From | Shaohua Li <> | Date | Tue, 12 Jul 2011 09:37:52 +0800 |
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Hi, Currently when the last queue of a service tree/group is empty, CFQ doesn't expire the queue. This is to allow requests from the tree/group come soon, so tree/group doesn't miss its share. But if the think time is big, the assumption isn't correct. idling the queue is just wasting bandwidth.
Originally I was hoping this can resolve Vivek's fsync issue, but it doesn't. The fsync issue is caused by queue idling. But since think time check only helps for think time above default queue idle time (8ms), think time check doesn't help for the fsync issue.
On the other hand, think time check is still helpful for queues with think time. I had test case in follow patches show throughput improvement without sacrifice tree/group shares.
v1->v2: 1. addressed some good comments from Vivek 2. add more test to make sure the patches don't change behavior of queues without think time.
Thanks, Shaohua
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