From: "Emilio G. Cota" <cota@braap.org>
To: QEMU Developers <qemu-devel@nongnu.org>,
MTTCG Devel <mttcg@listserver.greensocs.com>
Cc: "Alex Bennée" <alex.bennee@linaro.org>,
"Paolo Bonzini" <pbonzini@redhat.com>,
"Richard Henderson" <rth@twiddle.net>,
"Sergey Fedorov" <serge.fdrv@gmail.com>
Subject: [Qemu-devel] [PATCH v2 0/3] atomics: fix RCU perf. regression + update documentation
Date: Tue, 24 May 2016 16:06:11 -0400 [thread overview]
Message-ID: <1464120374-8950-1-git-send-email-cota@braap.org> (raw)
v1: https://lists.gnu.org/archive/html/qemu-devel/2016-05/msg03661.html
Patch 1 hasn't changed from v1 (where it was patch 2 though).
Patches 2 and 3 fix a not-so-small-after-all RCU performance regression
we introduced when transitioning to __atomic primitives. I got
an arm64 machine to test today and a workload that issues a lot of
atomic_read_rcu's, such as a 100%-lookup qht-bench test,
can gain ~12% in performance. [ in v1's 0/2 message I mentioned rcutorture;
It turns out it's not as dependent on atomic_read_rcu as I thought,
so it's not a good benchmark to measure this effect. ]
Thanks,
Emilio
next reply other threads:[~2016-05-24 20:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-24 20:06 Emilio G. Cota [this message]
2016-05-24 20:06 ` [Qemu-devel] [PATCH v2 1/3] docs/atomics: update atomic_read/set comparison with Linux Emilio G. Cota
2016-05-25 12:13 ` Paolo Bonzini
2016-05-24 20:06 ` [Qemu-devel] [PATCH v2 2/3] atomics: emit an smp_read_barrier_depends() barrier only for Sparc and Thread Sanitizer Emilio G. Cota
2016-05-24 20:09 ` Sergey Fedorov
2016-05-24 20:44 ` Emilio G. Cota
2016-05-25 12:16 ` Paolo Bonzini
2016-05-25 15:06 ` Emilio G. Cota
2016-05-24 20:06 ` [Qemu-devel] [PATCH v2 3/3] atomics: do not emit consume barrier for atomic_rcu_read Emilio G. Cota
2016-05-25 12:20 ` Paolo Bonzini
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