Messages in this thread | | | Subject | Re: [PATCH -next 00/11] support concurrent sync io for bfq on a specail occasion | From | "yukuai (C)" <> | Date | Fri, 11 Mar 2022 14:31:58 +0800 |
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friendly ping ...
在 2022/03/05 17:11, Yu Kuai 写道: > 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(). > > This patchset tries to support concurrent sync io if all the sync ios > are issued from the same cgroup: > > 1) Count root_group into 'num_groups_with_pending_reqs', patch 1-5; > > 2) Don't idle if 'num_groups_with_pending_reqs' is 1, patch 6; > > 3) Don't count the group if the group doesn't have pending requests, > while it's child groups may have pending requests, patch 7; > > This is because, for example: > if sync ios are issued from cgroup /root/c1/c2, root, c1 and c2 > will all be counted into 'num_groups_with_pending_reqs', > which makes it impossible to handle sync ios concurrently. > > 4) Decrease 'num_groups_with_pending_reqs' when the last queue completes > all the requests, while child groups may still have pending > requests, patch 8-10; > > This is because, for example: > t1 issue sync io on root group, t2 and t3 issue sync io on the same > child group. num_groups_with_pending_reqs is 2 now. > After t1 stopped, num_groups_with_pending_reqs is still 2. sync io from > t2 and t3 still can't be handled concurrently. > > 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 > v5.17-rc6: 550 Mib/s > v5.17-rc6-patched: 550 Mib/s > > running fio on non-root cgroup > v5.17-rc6: 349 Mib/s > v5.17-rc6-patched: 550 Mib/s > > Yu Kuai (11): > block, bfq: add new apis to iterate bfq entities > block, bfq: apply news apis where root group is not expected > block, bfq: cleanup for __bfq_activate_requeue_entity() > block, bfq: move the increasement of 'num_groups_with_pending_reqs' to > it's caller > block, bfq: count root group into 'num_groups_with_pending_reqs' > block, bfq: do not idle if only one cgroup is activated > block, bfq: only count parent bfqg when bfqq is activated > block, bfq: record how many queues have pending requests in bfq_group > block, bfq: move forward __bfq_weights_tree_remove() > block, bfq: decrease 'num_groups_with_pending_reqs' earlier > block, bfq: cleanup bfqq_group() > > block/bfq-cgroup.c | 13 +++---- > block/bfq-iosched.c | 87 +++++++++++++++++++++++---------------------- > block/bfq-iosched.h | 41 +++++++++++++-------- > block/bfq-wf2q.c | 56 +++++++++++++++-------------- > 4 files changed, 106 insertions(+), 91 deletions(-) >
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