Hi, could you please add pointers to the thread(s) where we have already revised this series (if we have). I don't see any reference to that in this cover letter. Paolo > Il giorno 17 mar 2022, alle ore 02:49, yukuai (C) <yukuai3@xxxxxxxxxx> ha scritto: > > friendly ping ... > > 在 2022/03/11 14:31, yukuai (C) 写道: >> 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(-) >>>
