lkml.org 
[lkml]   [2011]   [Feb]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 3/6 v4] cfq-iosched: Introduce vdisktime and io weight for CFQ queue
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
>


\
 
 \ /
  Last update: 2011-02-15 02:49    [from the cache]
©2003-2014 Jasper Spaans. Advertise on this site