From: "Michael S. Tsirkin" <mst@redhat.com>
To: Yunsheng Lin <linyunsheng@huawei.com>
Cc: davem@davemloft.net, kuba@kernel.org, jasowang@redhat.com,
brouer@redhat.com, paulmck@kernel.org, peterz@infradead.org,
will@kernel.org, shuah@kernel.org, linux-kernel@vger.kernel.org,
netdev@vger.kernel.org, linux-kselftest@vger.kernel.org,
linuxarm@openeuler.org
Subject: Re: [PATCH net-next v2 2/2] ptr_ring: make __ptr_ring_empty() checking more reliable
Date: Sun, 27 Jun 2021 02:07:13 -0400 [thread overview]
Message-ID: <20210627020440-mutt-send-email-mst@kernel.org> (raw)
In-Reply-To: <77615160-6f4f-64bf-7de9-b0adaddd5f06@huawei.com>
On Fri, Jun 25, 2021 at 05:20:10PM +0800, Yunsheng Lin wrote:
> On 2021/6/25 14:39, Michael S. Tsirkin wrote:
> > On Fri, Jun 25, 2021 at 11:18:56AM +0800, Yunsheng Lin wrote:
> >> Currently r->queue[] is cleared after r->consumer_head is moved
> >> forward, which makes the __ptr_ring_empty() checking called in
> >> page_pool_refill_alloc_cache() unreliable if the checking is done
> >> after the r->queue clearing and before the consumer_head moving
> >> forward.
> >>
> >> Move the r->queue[] clearing after consumer_head moving forward
> >> to make __ptr_ring_empty() checking more reliable.
> >>
> >> As a side effect of above change, a consumer_head checking is
> >> avoided for the likely case, and it has noticeable performance
> >> improvement when it is tested using the ptr_ring_test selftest
> >> added in the previous patch.
> >>
> >> Using "taskset -c 1 ./ptr_ring_test -s 1000 -m 0 -N 100000000"
> >> to test the case of single thread doing both the enqueuing and
> >> dequeuing:
> >>
> >> arch unpatched patched delta
> >> arm64 4648 ms 4464 ms +3.9%
> >> X86 2562 ms 2401 ms +6.2%
> >>
> >> Using "taskset -c 1-2 ./ptr_ring_test -s 1000 -m 1 -N 100000000"
> >> to test the case of one thread doing enqueuing and another thread
> >> doing dequeuing concurrently, also known as single-producer/single-
> >> consumer:
> >>
> >> arch unpatched patched delta
> >> arm64 3624 ms + 3624 ms 3462 ms + 3462 ms +4.4%
> >> x86 2758 ms + 2758 ms 2547 ms + 2547 ms +7.6%
> >
> > Nice but it's small - could be a fluke.
> > How many tests did you run? What is the variance?
> > Did you try pinning to different CPUs to observe numa effects?
> > Please use perf or some other modern tool for this kind
> > of benchmark. Thanks!
>
> The result is quite stable, and retest using perf stat：
How stable exactly? Try with -r so we can find out.
> ---------------unpatched ptr_ring.c begin----------------------------------
>
> perf stat ./ptr_ring_test -s 1000 -m 0 -N 100000000
> ptr_ring(size:1000) perf simple test for 100000000 times, took 2385198 us
>
> Performance counter stats for './ptr_ring_test -s 1000 -m 0 -N 100000000':
>
> 2385.49 msec task-clock # 1.000 CPUs utilized
> 26 context-switches # 0.011 K/sec
> 0 cpu-migrations # 0.000 K/sec
> 57 page-faults # 0.024 K/sec
> 6202023521 cycles # 2.600 GHz
> 17424187640 instructions # 2.81 insn per cycle
> <not supported> branches
> 6506477 branch-misses
>
> 2.385785170 seconds time elapsed
>
> 2.384014000 seconds user
> 0.000000000 seconds sys
>
>
> root@(none):~# perf stat ./ptr_ring_test -s 1000 -m 0 -N 100000000
> ptr_ring(size:1000) perf simple test for 100000000 times, took 2383385 us
>
> Performance counter stats for './ptr_ring_test -s 1000 -m 0 -N 100000000':
>
> 2383.67 msec task-clock # 1.000 CPUs utilized
> 26 context-switches # 0.011 K/sec
> 0 cpu-migrations # 0.000 K/sec
> 57 page-faults # 0.024 K/sec
> 6197278066 cycles # 2.600 GHz
> 17424207772 instructions # 2.81 insn per cycle
> <not supported> branches
> 6495766 branch-misses
>
> 2.383941170 seconds time elapsed
>
> 2.382215000 seconds user
> 0.000000000 seconds sys
>
>
> root@(none):~# perf stat ./ptr_ring_test -s 1000 -m 0 -N 100000000
> ptr_ring(size:1000) perf simple test for 100000000 times, took 2390858 us
>
> Performance counter stats for './ptr_ring_test -s 1000 -m 0 -N 100000000':
>
> 2391.16 msec task-clock # 1.000 CPUs utilized
> 25 context-switches # 0.010 K/sec
> 0 cpu-migrations # 0.000 K/sec
> 57 page-faults # 0.024 K/sec
> 6216704120 cycles # 2.600 GHz
> 17424243041 instructions # 2.80 insn per cycle
> <not supported> branches
> 6483886 branch-misses
>
> 2.391420440 seconds time elapsed
>
> 2.389647000 seconds user
> 0.000000000 seconds sys
>
>
> root@(none):~# perf stat ./ptr_ring_test -s 1000 -m 0 -N 100000000
> ptr_ring(size:1000) perf simple test for 100000000 times, took 2389810 us
>
> Performance counter stats for './ptr_ring_test -s 1000 -m 0 -N 100000000':
>
> 2390.10 msec task-clock # 1.000 CPUs utilized
> 26 context-switches # 0.011 K/sec
> 0 cpu-migrations # 0.000 K/sec
> 58 page-faults # 0.024 K/sec
> 6213995715 cycles # 2.600 GHz
> 17424227499 instructions # 2.80 insn per cycle
> <not supported> branches
> 6474069 branch-misses
>
> 2.390367070 seconds time elapsed
>
> 2.388644000 seconds user
> 0.000000000 seconds sys
>
> ---------------unpatched ptr_ring.c end----------------------------------
>
>
>
> ---------------patched ptr_ring.c begin----------------------------------
> root@(none):~# perf stat ./ptr_ring_test_opt -s 1000 -m 0 -N 100000000
> ptr_ring(size:1000) perf simple test for 100000000 times, took 2198894 us
>
> Performance counter stats for './ptr_ring_test_opt -s 1000 -m 0 -N 100000000':
>
> 2199.18 msec task-clock # 1.000 CPUs utilized
> 23 context-switches # 0.010 K/sec
> 0 cpu-migrations # 0.000 K/sec
> 56 page-faults # 0.025 K/sec
> 5717671859 cycles # 2.600 GHz
> 16124164124 instructions # 2.82 insn per cycle
> <not supported> branches
> 6564829 branch-misses
>
> 2.199445990 seconds time elapsed
>
> 2.197859000 seconds user
> 0.000000000 seconds sys
>
>
> root@(none):~# perf stat ./ptr_ring_test_opt -s 1000 -m 0 -N 100000000
> ptr_ring(size:1000) perf simple test for 100000000 times, took 2222337 us
>
> Performance counter stats for './ptr_ring_test_opt -s 1000 -m 0 -N 100000000':
>
> 2222.63 msec task-clock # 1.000 CPUs utilized
> 23 context-switches # 0.010 K/sec
> 0 cpu-migrations # 0.000 K/sec
> 57 page-faults # 0.026 K/sec
> 5778632853 cycles # 2.600 GHz
> 16124210769 instructions # 2.79 insn per cycle
> <not supported> branches
> 6603904 branch-misses
>
> 2.222901020 seconds time elapsed
>
> 2.221312000 seconds user
> 0.000000000 seconds sys
>
>
> root@(none):~# perf stat ./ptr_ring_test_opt -s 1000 -m 0 -N 100000000
> ptr_ring(size:1000) perf simple test for 100000000 times, took 2251980 us
>
> Performance counter stats for './ptr_ring_test_opt -s 1000 -m 0 -N 100000000':
>
> 2252.28 msec task-clock # 1.000 CPUs utilized
> 25 context-switches # 0.011 K/sec
> 0 cpu-migrations # 0.000 K/sec
> 57 page-faults # 0.025 K/sec
> 5855668335 cycles # 2.600 GHz
> 16124310588 instructions # 2.75 insn per cycle
> <not supported> branches
> 6777279 branch-misses
>
> 2.252543340 seconds time elapsed
>
> 2.250897000 seconds user
> 0.000000000 seconds sys
>
>
> root@(none):~#
> root@(none):~# perf stat ./ptr_ring_test_opt -s 1000 -m 0 -N 100000000
> ptr_ring(size:1000) perf simple test for 100000000 times, took 2209415 us
>
> Performance counter stats for './ptr_ring_test_opt -s 1000 -m 0 -N 100000000':
>
> 2209.70 msec task-clock # 1.000 CPUs utilized
> 24 context-switches # 0.011 K/sec
> 0 cpu-migrations # 0.000 K/sec
> 58 page-faults # 0.026 K/sec
> 5745003772 cycles # 2.600 GHz
> 16124198886 instructions # 2.81 insn per cycle
> <not supported> branches
> 6508414 branch-misses
>
> 2.209973960 seconds time elapsed
>
> 2.208354000 seconds user
> 0.000000000 seconds sys
>
>
> root@(none):~# perf stat ./ptr_ring_test_opt -s 1000 -m 0 -N 100000000
> ptr_ring(size:1000) perf simple test for 100000000 times, took 2211409 us
>
> Performance counter stats for './ptr_ring_test_opt -s 1000 -m 0 -N 100000000':
>
> 2211.70 msec task-clock # 1.000 CPUs utilized
> 24 context-switches # 0.011 K/sec
> 0 cpu-migrations # 0.000 K/sec
> 57 page-faults # 0.026 K/sec
> 5750136694 cycles # 2.600 GHz
> 16124176577 instructions # 2.80 insn per cycle
> <not supported> branches
> 6553023 branch-misses
>
> 2.211968470 seconds time elapsed
>
> 2.210303000 seconds user
> 0.000000000 seconds sys
>
> ---------------patched ptr_ring.c end----------------------------------
>
> >
> >>
>
next prev parent reply other threads:[~2021-06-27 6:07 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-25 3:18 [PATCH net-next v2 0/2] add benchmark selftest and optimization for ptr_ring Yunsheng Lin
2021-06-25 3:18 ` [PATCH net-next v2 1/2] selftests/ptr_ring: add benchmark application " Yunsheng Lin
2021-06-25 3:36 ` Jason Wang
2021-06-25 3:52 ` Yunsheng Lin
2021-06-27 6:09 ` Michael S. Tsirkin
2021-06-28 1:42 ` Yunsheng Lin
2021-06-25 6:37 ` Michael S. Tsirkin
2021-06-25 7:40 ` Yunsheng Lin
2021-06-25 3:18 ` [PATCH net-next v2 2/2] ptr_ring: make __ptr_ring_empty() checking more reliable Yunsheng Lin
2021-06-25 6:32 ` Michael S. Tsirkin
2021-06-25 7:21 ` Yunsheng Lin
2021-06-25 7:30 ` Michael S. Tsirkin
2021-06-25 8:33 ` Yunsheng Lin
2021-06-27 6:03 ` Michael S. Tsirkin
2021-06-28 2:17 ` Yunsheng Lin
2021-06-25 6:39 ` Michael S. Tsirkin
2021-06-25 9:20 ` Yunsheng Lin
2021-06-27 6:07 ` Michael S. Tsirkin [this message]
2021-06-28 2:11 ` [Linuxarm] " Yunsheng Lin
2021-06-25 6:42 ` [PATCH net-next v2 0/2] add benchmark selftest and optimization for ptr_ring Michael S. Tsirkin
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