From: "Emilio G. Cota" <cota@braap.org>
To: Pranith Kumar <bobby.prani@gmail.com>
Cc: qemu-devel <qemu-devel@nongnu.org>,
"Richard Henderson" <rth@twiddle.net>,
"Alex Bennée" <alex.bennee@linaro.org>,
"Peter Maydell" <peter.maydell@linaro.org>,
"Paolo Bonzini" <pbonzini@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v2 1/3] compiler: define QEMU_CACHELINE_SIZE
Date: Tue, 6 Jun 2017 12:11:52 -0400 [thread overview]
Message-ID: <20170606161152.GA6109@flamenco> (raw)
In-Reply-To: <CAJhHMCDHLrU5NEuZGJqkVcJyQnXYsrdcYbNiNw4DAgiT=0R9pQ@mail.gmail.com>
On Tue, Jun 06, 2017 at 01:39:45 -0400, Pranith Kumar wrote:
> On Mon, Jun 5, 2017 at 6:49 PM, Emilio G. Cota <cota@braap.org> wrote:
> > This is a constant used as a hint for padding structs to hopefully avoid
> > false cache line sharing.
> >
> > The constant can be set at configure time by defining QEMU_CACHELINE_SIZE
> > via --extra-cflags. If not set there, we try to obtain the value from
> > the machine running the configure script. If we fail, we default to
> > reasonable values, i.e. 128 bytes for ppc64 and 64 bytes for all others.
(snip)
> Is there any reason not to use sysconf(_SC_LEVEL1_DCACHE_LINESIZE)?
I tried using sysconf, but it doesn't work on the PowerPC machine I have
access to (it returns 0). It might be a machine-specific thing though-I
don't know. Here's the machine's `uname -a':
Linux gcc2-power8.osuosl.org 3.10.0-514.10.2.el7.ppc64le #1 SMP Fri Mar \
3 16:16:38 GMT 2017 ppc64le ppc64le ppc64le GNU/Linux
E.
next prev parent reply other threads:[~2017-06-06 16:11 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-05 22:49 [Qemu-devel] [PATCH v2 0/3] tcg: allocate TB structs preceding translated code Emilio G. Cota
2017-06-05 22:49 ` [Qemu-devel] [PATCH v2 1/3] compiler: define QEMU_CACHELINE_SIZE Emilio G. Cota
2017-06-06 5:39 ` Pranith Kumar
2017-06-06 8:18 ` Richard Henderson
2017-06-06 16:11 ` Emilio G. Cota [this message]
2017-06-06 17:39 ` Richard Henderson
2017-06-06 20:28 ` Geert Martin Ijewski
2017-06-06 21:38 ` Emilio G. Cota
2017-06-06 22:01 ` Geert Martin Ijewski
2017-06-05 22:49 ` [Qemu-devel] [PATCH v2 2/3] tests: use QEMU_CACHELINE_SIZE instead of hard-coding it Emilio G. Cota
2017-06-06 5:40 ` Pranith Kumar
2017-06-05 22:49 ` [Qemu-devel] [PATCH v2 3/3] tcg: allocate TB structs before the corresponding translated code Emilio G. Cota
2017-06-06 5:36 ` Pranith Kumar
2017-06-06 17:13 ` Emilio G. Cota
2017-06-06 8:24 ` Richard Henderson
2017-06-06 16:25 ` Emilio G. Cota
2017-06-06 17:02 ` Richard Henderson
2017-06-06 17:31 ` Emilio G. Cota
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