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From: "Alex Bennée" <alex.bennee@linaro.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Sergey Fedorov <sergey.fedorov@linaro.org>,
	qemu-devel@nongnu.org, mttcg@listserver.greensocs.com,
	fred.konrad@greensocs.com, a.rigo@virtualopensystems.com,
	serge.fdrv@gmail.com, cota@braap.org, bobby.prani@gmail.com,
	rth@twiddle.net, peter.maydell@linaro.org, patches@linaro.org,
	claudio.fontana@huawei.com, mark.burton@greensocs.com,
	jan.kiszka@siemens.com
Subject: Re: [Qemu-devel] [PATCH v3 00/11] Reduce lock contention on TCG hot-path
Date: Thu, 14 Jul 2016 13:02:01 +0100	[thread overview]
Message-ID: <87wpko4edi.fsf@linaro.org> (raw)
In-Reply-To: <148a0c48-f58c-6d95-8b97-6449670019ac@redhat.com>


Paolo Bonzini <pbonzini@redhat.com> writes:

> On 12/07/2016 22:13, Sergey Fedorov wrote:
>> From: Sergey Fedorov <serge.fdrv@gmail.com>
<snip>
>
> Have you measured performance with the series?  In any case, it's nice
> to see MTTCG finally taking shape!

Here are some numbers on the multi-threaded pigz test:

Before:

retry.py called with ['./arm-linux-user/qemu-arm', './pigz.armhf', '-c', '-9', 'linux-4.6.3.tar']
Source code is @ pull-tcg-20160708-104-g9ec3025 or heads/review/hot-patch-v3
run 1: ret=0 (PASS), time=32.285497 (1/1)
run 2: ret=0 (PASS), time=32.035293 (2/2)
run 3: ret=0 (PASS), time=31.784781 (3/3)
run 4: ret=0 (PASS), time=32.035136 (4/4)
run 5: ret=0 (PASS), time=32.285612 (5/5)
Results summary:
0: 5 times (100.00%), avg time 32.085 (0.04 varience/0.21 deviation)

After:

Ran command 5 times, 5 passes
retry.py called with ['./arm-linux-user/qemu-arm', './pigz.armhf', '-c', '-9', 'linux-4.6.3.tar']
Source code is @ pull-tcg-20160708-115-gf317fa8 or heads/review/hot-patch-v3
run 1: ret=0 (PASS), time=29.281950 (1/1)
run 2: ret=0 (PASS), time=29.285588 (2/2)
run 3: ret=0 (PASS), time=29.282065 (3/3)
run 4: ret=0 (PASS), time=29.282397 (4/4)
run 5: ret=0 (PASS), time=29.282045 (5/5)
Results summary:
0: 5 times (100.00%), avg time 29.283 (0.00 varience/0.00 deviation)
Ran command 5 times, 5 passes

Which gives a roughly 10% improvement for heavily threaded code.

Looking at the perf data it looks like the hotest part of the code now
is cpu_get_tb_cpu_state which is required to get the initial hash to
search for the next tb.

--
Alex Bennée

  parent reply	other threads:[~2016-07-14 12:02 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-12 20:13 [Qemu-devel] [PATCH v3 00/11] Reduce lock contention on TCG hot-path Sergey Fedorov
2016-07-12 20:13 ` [Qemu-devel] [PATCH v3 01/11] util/qht: Document memory ordering assumptions Sergey Fedorov
2016-07-12 23:19   ` Emilio G. Cota
2016-07-13  7:36     ` Paolo Bonzini
2016-07-13 17:50       ` Sergey Fedorov
2016-07-14 13:56         ` Paolo Bonzini
2016-07-14 14:08           ` Sergey Fedorov
2016-07-13 11:13   ` Paolo Bonzini
2016-07-13 18:03     ` Sergey Fedorov
2016-07-14  8:05       ` Paolo Bonzini
2016-07-15 12:37     ` Sergey Fedorov
2016-07-15 12:51       ` Paolo Bonzini
2016-07-15 13:18         ` Sergey Fedorov
2016-07-12 20:13 ` [Qemu-devel] [PATCH v3 02/11] cpu-exec: Pass last_tb by value to tb_find_fast() Sergey Fedorov
2016-07-12 20:13 ` [Qemu-devel] [PATCH v3 03/11] tcg: Prepare safe tb_jmp_cache lookup out of tb_lock Sergey Fedorov
2016-07-14 12:14   ` Alex Bennée
2016-07-12 20:13 ` [Qemu-devel] [PATCH v3 04/11] tcg: Prepare safe access to tb_flushed " Sergey Fedorov
2016-07-14 12:45   ` Alex Bennée
2016-07-14 12:55     ` Sergey Fedorov
2016-07-14 13:12       ` Alex Bennée
2016-07-12 20:13 ` [Qemu-devel] [PATCH v3 05/11] target-i386: Remove redundant HF_SOFTMMU_MASK Sergey Fedorov
2016-07-14 12:19   ` Alex Bennée
2016-07-12 20:13 ` [Qemu-devel] [PATCH v3 06/11] tcg: Introduce tb_mark_invalid() and tb_is_invalid() Sergey Fedorov
2016-07-14 10:25   ` Alex Bennée
2016-07-14 11:10     ` Sergey Fedorov
2016-07-14 11:48       ` Paolo Bonzini
2016-07-14 12:04         ` Alex Bennée
2016-07-14 12:53   ` Alex Bennée
2016-07-14 13:00     ` Sergey Fedorov
2016-07-14 13:12       ` Paolo Bonzini
2016-07-14 13:15       ` Alex Bennée
2016-07-12 20:13 ` [Qemu-devel] [PATCH v3 07/11] tcg: Prepare TB invalidation for lockless TB lookup Sergey Fedorov
2016-07-14 12:59   ` Alex Bennée
2016-07-14 13:11     ` Sergey Fedorov
2016-07-12 20:13 ` [Qemu-devel] [PATCH v3 08/11] tcg: set up tb->page_addr before insertion Sergey Fedorov
2016-07-12 20:13 ` [Qemu-devel] [PATCH v3 09/11] tcg: cpu-exec: remove tb_lock from the hot-path Sergey Fedorov
2016-07-12 20:13 ` [Qemu-devel] [PATCH v3 10/11] tcg: Avoid bouncing tb_lock between tb_gen_code() and tb_add_jump() Sergey Fedorov
2016-07-14 13:01   ` Alex Bennée
2016-07-14 13:13     ` Sergey Fedorov
2016-07-12 20:13 ` [Qemu-devel] [PATCH v3 11/11] tcg: Merge tb_find_slow() and tb_find_fast() Sergey Fedorov
2016-07-14 13:02   ` Alex Bennée
2016-07-13  7:39 ` [Qemu-devel] [PATCH v3 00/11] Reduce lock contention on TCG hot-path Paolo Bonzini
2016-07-13 17:00   ` Sergey Fedorov
2016-07-14  9:55     ` Alex Bennée
2016-07-14 11:13       ` Sergey Fedorov
2016-07-13 18:06   ` Sergey Fedorov
2016-07-14 12:02   ` Alex Bennée [this message]
2016-07-14 12:10     ` Paolo Bonzini
2016-07-14 13:13       ` Alex Bennée

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