From: Dave Watson <davejwatson@fb.com>
To: Andy Lutomirski <luto@amacapital.net>
Cc: <kernel-team@fb.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Linux API <linux-api@vger.kernel.org>,
Paul Turner <pjt@google.com>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Subject: Re: [RFC PATCH 0/3] restartable sequences benchmarks
Date: Thu, 22 Oct 2015 15:10:54 -0700 [thread overview]
Message-ID: <20151022221054.GA2949757@devbig217.prn1.facebook.com> (raw)
In-Reply-To: <CALCETrWXR0BMeEygiLoT5gbyYpGxren_Fch=S4RSryfqwdxH8g@mail.gmail.com>
On Thu, Oct 22, 2015 at 12:11:42PM -0700, Andy Lutomirski wrote:
> On Thu, Oct 22, 2015 at 11:06 AM, Dave Watson <davejwatson@fb.com> wrote:
> >
> > RSS CPUIDLE LATENCYMS
> > jemalloc 4.0.0 31G 33% 390
> > jemalloc + this patch 25G 33% 390
> > jemalloc + this patch using lsl 25G 30% 420
> > jemalloc + PT's rseq patch 25G 32% 405
> > glibc malloc 2.20 27G 30% 420
> > tcmalloc gperftools trunk (2.2) 21G 30% 480
>
> Slightly confused. This is showing a space efficiency improvement but
> not a performance improvement? Is the idea that percpu free lists are
> more space efficient than per-thread free lists?
>
> --Andy
Correct - the service was already tuned such that most requests hit
the (very large) thread free lists to avoided taking expensive locks
talking to the central arena. There were more threads than cpus, so
the memory win is just needing fewer free lists.
prev parent reply other threads:[~2015-10-22 22:11 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-10-22 18:06 [RFC PATCH 0/3] restartable sequences benchmarks Dave Watson
2015-10-22 18:06 ` [RFC PATCH 1/3] restartable sequences: user-space per-cpu critical sections Dave Watson
2015-10-22 18:53 ` kbuild test robot
2015-10-22 19:35 ` kbuild test robot
2015-10-22 18:06 ` [RFC PATCH 2/3] restartable sequences: x86 ABI Dave Watson
2015-10-22 18:07 ` [RFC PATCH 3/3] restartable sequences: basic user-space self-tests Dave Watson
2015-10-22 19:11 ` [RFC PATCH 0/3] restartable sequences benchmarks Andy Lutomirski
2015-10-22 22:10 ` Dave Watson [this message]
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