Messages in this thread |  | | | Date | Tue, 15 Feb 2011 09:46:28 +0800 | | From | Gui Jianfeng <> | | Subject | Re: [PATCH 3/6 v4] cfq-iosched: Introduce vdisktime and io weight for CFQ queue |
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Vivek Goyal wrote: > On Thu, Feb 10, 2011 at 03:47:16PM +0800, Gui Jianfeng wrote: > > [..] >> +/* >> + * The time when a CFQ queue is put onto a service tree is recoreded in >> + * cfqq->reposition_time. Currently, we check the first priority CFQ queues >> + * on each service tree, and select the workload type that contains the lowest >> + * reposition_time CFQ queue among them. >> + */ >> static enum wl_type_t cfq_choose_wl(struct cfq_data *cfqd, >> struct cfq_group *cfqg, enum wl_prio_t prio) >> { >> struct cfq_entity *cfqe; >> + struct cfq_queue *cfqq; >> + unsigned long lowest_start_time; >> int i; >> - bool key_valid = false; >> - unsigned long lowest_key = 0; >> + bool time_valid = false; >> enum wl_type_t cur_best = SYNC_NOIDLE_WORKLOAD; >> >> + /* >> + * TODO: We may take io priority and io class into account when >> + * choosing a workload type. But for the time being just make use of >> + * reposition_time only. >> + */ >> for (i = 0; i <= SYNC_WORKLOAD; ++i) { >> - /* select the one with lowest rb_key */ >> cfqe = cfq_rb_first(service_tree_for(cfqg, prio, i)); >> - if (cfqe && >> - (!key_valid || time_before(cfqe->rb_key, lowest_key))) { >> - lowest_key = cfqe->rb_key; >> + cfqq = cfqq_of_entity(cfqe); >> + if (cfqe && (!time_valid || >> + time_before(cfqq->reposition_time, >> + lowest_start_time))) { >> + lowest_start_time = cfqq->reposition_time; > > Gui, > > Have you had a chance to run some mixed workloads in a group (some sync, > some async and some sync-idle queues), and see how latency and throughput > of sync-idle workload changes due to this "resposition_time" logic. I > just want to make sure that latency of sync-noidle workload does not > go up as that's the workload that people care and gets noticed first.
Hi Vivek
Will do some tests.
Thanks, Gui
> > Thanks > Vivek >
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