Messages in this thread | | | Subject | Re: [PATCH -next v5 0/3] support concurrent sync io for bfq on a specail occasion | From | "yukuai (C)" <> | Date | Sat, 14 May 2022 17:29:09 +0800 |
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在 2022/05/05 9:00, yukuai (C) 写道: > Hi, Paolo > > Can you take a look at this patchset? It has been quite a long time > since we spotted this problem... >
friendly ping ... > Thanks, > Kuai > > 在 2022/04/28 20:08, Yu Kuai 写道: >> Changes in v5: >> - rename bfq_add_busy_queues() to bfq_inc_busy_queues() in patch 1 >> - fix wrong definition in patch 1 >> - fix spelling mistake in patch 2: leaset -> least >> - update comments in patch 3 >> - add reviewed-by tag in patch 2,3 >> >> Changes in v4: >> - split bfq_update_busy_queues() to bfq_add/dec_busy_queues(), >> suggested by Jan Kara. >> - remove unused 'in_groups_with_pending_reqs', >> >> Changes in v3: >> - remove the cleanup patch that is irrelevant now(I'll post it >> separately). >> - instead of hacking wr queues and using weights tree >> insertion/removal, >> using bfq_add/del_bfqq_busy() to count the number of groups >> (suggested by Jan Kara). >> >> Changes in v2: >> - Use a different approch to count root group, which is much simple. >> >> Currently, bfq can't handle sync io concurrently as long as they >> are not issued from root group. This is because >> 'bfqd->num_groups_with_pending_reqs > 0' is always true in >> bfq_asymmetric_scenario(). >> >> The way that bfqg is counted into 'num_groups_with_pending_reqs': >> >> Before this patchset: >> 1) root group will never be counted. >> 2) Count if bfqg or it's child bfqgs have pending requests. >> 3) Don't count if bfqg and it's child bfqgs complete all the requests. >> >> After this patchset: >> 1) root group is counted. >> 2) Count if bfqg have at least one bfqq that is marked busy. >> 3) Don't count if bfqg doesn't have any busy bfqqs. >> >> The main reason to use busy state of bfqq instead of 'pending requests' >> is that bfqq can stay busy after dispatching the last request if idling >> is needed for service guarantees. >> >> With the above changes, concurrent sync io can be supported if only >> one group is activated. >> >> fio test script(startdelay is used to avoid queue merging): >> [global] >> filename=/dev/nvme0n1 >> allow_mounted_write=0 >> ioengine=psync >> direct=1 >> ioscheduler=bfq >> offset_increment=10g >> group_reporting >> rw=randwrite >> bs=4k >> >> [test1] >> numjobs=1 >> >> [test2] >> startdelay=1 >> numjobs=1 >> >> [test3] >> startdelay=2 >> numjobs=1 >> >> [test4] >> startdelay=3 >> numjobs=1 >> >> [test5] >> startdelay=4 >> numjobs=1 >> >> [test6] >> startdelay=5 >> numjobs=1 >> >> [test7] >> startdelay=6 >> numjobs=1 >> >> [test8] >> startdelay=7 >> numjobs=1 >> >> test result: >> running fio on root cgroup >> v5.18-rc1: 550 Mib/s >> v5.18-rc1-patched: 550 Mib/s >> >> running fio on non-root cgroup >> v5.18-rc1: 349 Mib/s >> v5.18-rc1-patched: 550 Mib/s >> >> Note that I also test null_blk with "irqmode=2 >> completion_nsec=100000000(100ms) hw_queue_depth=1", and tests show >> that service guarantees are still preserved. >> >> Previous versions: >> RFC: >> https://lore.kernel.org/all/20211127101132.486806-1-yukuai3@huawei.com/ >> v1: >> https://lore.kernel.org/all/20220305091205.4188398-1-yukuai3@huawei.com/ >> v2: >> https://lore.kernel.org/all/20220416093753.3054696-1-yukuai3@huawei.com/ >> v3: >> https://lore.kernel.org/all/20220427124722.48465-1-yukuai3@huawei.com/ >> v4: >> https://lore.kernel.org/all/20220428111907.3635820-1-yukuai3@huawei.com/ >> >> Yu Kuai (3): >> block, bfq: record how many queues are busy in bfq_group >> block, bfq: refactor the counting of 'num_groups_with_pending_reqs' >> block, bfq: do not idle if only one group is activated >> >> block/bfq-cgroup.c | 1 + >> block/bfq-iosched.c | 48 +++----------------------------------- >> block/bfq-iosched.h | 57 +++++++-------------------------------------- >> block/bfq-wf2q.c | 35 +++++++++++++++++----------- >> 4 files changed, 35 insertions(+), 106 deletions(-) >>
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