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Message-ID: <b5ee609d-e104-bc91-f0d4-21e27d411ab8@huawei.com>
Date: Fri, 8 Apr 2022 14:50:47 +0800
From: "yukuai (C)" <yukuai3@...wei.com>
To: <tj@...nel.org>, <axboe@...nel.dk>, <paolo.valente@...aro.org>,
<jack@...e.cz>
CC: <cgroups@...r.kernel.org>, <linux-block@...r.kernel.org>,
<linux-kernel@...r.kernel.org>, <yi.zhang@...wei.com>
Subject: Re: [PATCH -next 00/11] support concurrent sync io for bfq on a
specail occasion
friendly ping ...
在 2022/04/01 11:43, yukuai (C) 写道:
> friendly ping ...
>
> 在 2022/03/25 15:30, yukuai (C) 写道:
>> friendly ping ...
>>
>> 在 2022/03/17 9:49, yukuai (C) 写道:
>>> 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(-)
>>>>>
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