From: David Howells <dhowells@redhat.com>
To: Christoph Hellwig <hch@infradead.org>
Cc: dhowells@redhat.com, Pavel Begunkov <asml.silence@gmail.com>,
Matthew Wilcox <willy@infradead.org>,
Jens Axboe <axboe@kernel.dk>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-fsdevel@vger.kernel.org, linux-block@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 01/29] iov_iter: Switch to using a table of operations
Date: Mon, 23 Nov 2020 10:31:14 +0000 [thread overview]
Message-ID: <516984.1606127474@warthog.procyon.org.uk> (raw)
In-Reply-To: <20201123080506.GA30578@infradead.org>
Christoph Hellwig <hch@infradead.org> wrote:
> Please run performance tests. I think the indirect calls could totally
> wreck things like high performance direct I/O, especially using io_uring
> on x86.
Here's an initial test using fio and null_blk. I left null_blk in its default
configuration and used the following command line:
fio --ioengine=libaio --direct=1 --gtod_reduce=1 --name=readtest --filename=/dev/nullb0 --bs=4k --iodepth=128 --time_based --runtime=120 --readwrite=randread --iodepth_low=96 --iodepth_batch=16 --numjobs=4
I borrowed some of the parameters from an email I found online, so I'm not
sure if they're that useful.
I tried three different sets of patches: none, just the first (which adds the
jump table without getting rid of the conditional branches), and all of them.
I'm not sure which stats are of particular interest here, so I took the two
summary stats from the output of fio and also added together the "issued rwts:
total=a,b,c,d" from each test thread (only the first of which is non-zero).
The CPU is an Intel(R) Core(TM) i3-4170 CPU @ 3.70GHz, so 4 single-thread
cores, and 16G of RAM. No virtualisation is involved.
Unpatched:
READ: bw=4109MiB/s (4308MB/s), 1025MiB/s-1029MiB/s (1074MB/s-1079MB/s), io=482GiB (517GB), run=120001-120001msec
READ: bw=4097MiB/s (4296MB/s), 1020MiB/s-1029MiB/s (1070MB/s-1079MB/s), io=480GiB (516GB), run=120001-120001msec
READ: bw=4113MiB/s (4312MB/s), 1025MiB/s-1031MiB/s (1075MB/s-1082MB/s), io=482GiB (517GB), run=120001-120001msec
READ: bw=4125MiB/s (4325MB/s), 1028MiB/s-1033MiB/s (1078MB/s-1084MB/s), io=483GiB (519GB), run=120001-120001msec
nullb0: ios=126017326/0, merge=53/0, ticks=3538817/0, in_queue=3538817, util=100.00%
nullb0: ios=125655193/0, merge=55/0, ticks=3548157/0, in_queue=3548157, util=100.00%
nullb0: ios=126133014/0, merge=58/0, ticks=3545621/0, in_queue=3545621, util=100.00%
nullb0: ios=126512562/0, merge=57/0, ticks=3531600/0, in_queue=3531600, util=100.00%
sum issued rwts = 126224632
sum issued rwts = 125861368
sum issued rwts = 126340344
sum issued rwts = 126718648
Just first patch:
READ: bw=4106MiB/s (4306MB/s), 1023MiB/s-1030MiB/s (1073MB/s-1080MB/s), io=481GiB (517GB), run=120001-120001msec
READ: bw=4126MiB/s (4327MB/s), 1029MiB/s-1034MiB/s (1079MB/s-1084MB/s), io=484GiB (519GB), run=120001-120001msec
READ: bw=4109MiB/s (4308MB/s), 1025MiB/s-1029MiB/s (1075MB/s-1079MB/s), io=481GiB (517GB), run=120001-120001msec
READ: bw=4097MiB/s (4296MB/s), 1023MiB/s-1025MiB/s (1073MB/s-1074MB/s), io=480GiB (516GB), run=120001-120001msec
nullb0: ios=125939152/0, merge=62/0, ticks=3534917/0, in_queue=3534917, util=100.00%
nullb0: ios=126554181/0, merge=61/0, ticks=3532067/0, in_queue=3532067, util=100.00%
nullb0: ios=126012346/0, merge=54/0, ticks=3530504/0, in_queue=3530504, util=100.00%
nullb0: ios=125653775/0, merge=54/0, ticks=3537438/0, in_queue=3537438, util=100.00%
sum issued rwts = 126144952
sum issued rwts = 126765368
sum issued rwts = 126215928
sum issued rwts = 125864120
All patches:
nullb0: ios=10477062/0, merge=2/0, ticks=284992/0, in_queue=284992, util=95.87%
nullb0: ios=10405246/0, merge=2/0, ticks=291886/0, in_queue=291886, util=99.82%
nullb0: ios=10425583/0, merge=1/0, ticks=291699/0, in_queue=291699, util=99.22%
nullb0: ios=10438845/0, merge=3/0, ticks=292445/0, in_queue=292445, util=99.31%
READ: bw=4118MiB/s (4318MB/s), 1028MiB/s-1032MiB/s (1078MB/s-1082MB/s), io=483GiB (518GB), run=120001-120001msec
READ: bw=4109MiB/s (4308MB/s), 1024MiB/s-1030MiB/s (1073MB/s-1080MB/s), io=481GiB (517GB), run=120001-120001msec
READ: bw=4108MiB/s (4308MB/s), 1026MiB/s-1029MiB/s (1076MB/s-1079MB/s), io=481GiB (517GB), run=120001-120001msec
READ: bw=4112MiB/s (4312MB/s), 1025MiB/s-1031MiB/s (1075MB/s-1081MB/s), io=482GiB (517GB), run=120001-120001msec
nullb0: ios=126282410/0, merge=58/0, ticks=3557384/0, in_queue=3557384, util=100.00%
nullb0: ios=126004837/0, merge=67/0, ticks=3565235/0, in_queue=3565235, util=100.00%
nullb0: ios=125988876/0, merge=59/0, ticks=3563026/0, in_queue=3563026, util=100.00%
nullb0: ios=126118279/0, merge=57/0, ticks=3566122/0, in_queue=3566122, util=100.00%
sum issued rwts = 126494904
sum issued rwts = 126214200
sum issued rwts = 126198200
sum issued rwts = 126328312
David
next prev parent reply other threads:[~2020-11-23 10:31 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-21 14:13 [PATCH 00/29] RFC: iov_iter: Switch to using an ops table David Howells
2020-11-21 14:13 ` [PATCH 01/29] iov_iter: Switch to using a table of operations David Howells
2020-11-21 14:31 ` Pavel Begunkov
2020-11-23 23:21 ` Pavel Begunkov
2020-11-21 18:21 ` Linus Torvalds
2020-12-11 1:30 ` Al Viro
2020-11-22 13:33 ` David Howells
2020-11-22 13:58 ` David Laight
2020-11-22 19:22 ` Linus Torvalds
2020-11-22 22:34 ` David Laight
2020-11-22 22:46 ` David Laight
2020-11-23 8:05 ` Christoph Hellwig
2020-11-23 10:31 ` David Howells [this message]
2020-11-23 23:42 ` Pavel Begunkov
2020-11-24 12:50 ` David Howells
2020-11-24 15:30 ` Jens Axboe
2020-11-27 17:14 ` David Howells
2020-11-23 11:14 ` David Howells
2020-12-03 6:45 ` [iov_iter] 9bd0e337c6: will-it-scale.per_process_ops -4.8% regression kernel test robot
2020-12-03 17:47 ` Linus Torvalds
2020-12-03 17:50 ` Jens Axboe
2020-12-04 11:50 ` David Howells
2020-12-04 11:51 ` David Howells
2020-12-07 13:10 ` Oliver Sang
2020-12-07 13:20 ` David Howells
2020-11-21 14:13 ` [PATCH 02/29] iov_iter: Split copy_page_to_iter() David Howells
2020-11-21 14:13 ` [PATCH 03/29] iov_iter: Split iov_iter_fault_in_readable David Howells
2020-11-21 14:13 ` [PATCH 04/29] iov_iter: Split the iterate_and_advance() macro David Howells
2020-11-21 14:14 ` [PATCH 05/29] iov_iter: Split copy_to_iter() David Howells
2020-11-21 14:14 ` [PATCH 06/29] iov_iter: Split copy_mc_to_iter() David Howells
2020-11-21 14:14 ` [PATCH 07/29] iov_iter: Split copy_from_iter() David Howells
2020-11-21 14:14 ` [PATCH 08/29] iov_iter: Split the iterate_all_kinds() macro David Howells
2020-11-21 14:14 ` [PATCH 09/29] iov_iter: Split copy_from_iter_full() David Howells
2020-11-21 14:14 ` [PATCH 10/29] iov_iter: Split copy_from_iter_nocache() David Howells
2020-11-21 14:14 ` [PATCH 11/29] iov_iter: Split copy_from_iter_flushcache() David Howells
2020-11-21 14:14 ` [PATCH 12/29] iov_iter: Split copy_from_iter_full_nocache() David Howells
2020-11-21 14:15 ` [PATCH 13/29] iov_iter: Split copy_page_from_iter() David Howells
2020-11-21 14:15 ` [PATCH 14/29] iov_iter: Split iov_iter_zero() David Howells
2020-11-21 14:15 ` [PATCH 15/29] iov_iter: Split copy_from_user_atomic() David Howells
2020-11-21 14:15 ` [PATCH 16/29] iov_iter: Split iov_iter_advance() David Howells
2020-11-21 14:15 ` [PATCH 17/29] iov_iter: Split iov_iter_revert() David Howells
2020-11-21 14:15 ` [PATCH 18/29] iov_iter: Split iov_iter_single_seg_count() David Howells
2020-11-21 14:15 ` [PATCH 19/29] iov_iter: Split iov_iter_alignment() David Howells
2020-11-21 14:15 ` [PATCH 20/29] iov_iter: Split iov_iter_gap_alignment() David Howells
2020-11-21 14:16 ` [PATCH 21/29] iov_iter: Split iov_iter_get_pages() David Howells
2020-11-21 14:16 ` [PATCH 22/29] iov_iter: Split iov_iter_get_pages_alloc() David Howells
2020-11-21 14:16 ` [PATCH 23/29] iov_iter: Split csum_and_copy_from_iter() David Howells
2020-11-21 14:16 ` [PATCH 24/29] iov_iter: Split csum_and_copy_from_iter_full() David Howells
2020-11-21 14:16 ` [PATCH 25/29] iov_iter: Split csum_and_copy_to_iter() David Howells
2020-11-21 14:16 ` [PATCH 26/29] iov_iter: Split iov_iter_npages() David Howells
2020-11-21 14:16 ` [PATCH 27/29] iov_iter: Split dup_iter() David Howells
2020-11-21 14:17 ` [PATCH 28/29] iov_iter: Split iov_iter_for_each_range() David Howells
2020-11-21 14:17 ` [PATCH 29/29] iov_iter: Remove iterate_all_kinds() and iterate_and_advance() David Howells
2020-11-21 14:34 ` [PATCH 00/29] RFC: iov_iter: Switch to using an ops table Pavel Begunkov
2020-11-21 18:23 ` Linus Torvalds
2020-12-11 3:24 ` Matthew Wilcox
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