From: Borislav Petkov <bp@alien8.de>
To: Wedson Almeida Filho <wedsonaf@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>, Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
x86@kernel.org, linux-kernel@vger.kernel.org,
Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>
Subject: Re: [PATCH] x86: Use asm-goto to implement mutex fast path on x86-64
Date: Tue, 2 Jul 2013 00:44:21 +0200 [thread overview]
Message-ID: <20130701224421.GL23515@pd.tnic> (raw)
In-Reply-To: <CANeycqoq8LwLMoXEYdPE6m9eKVB7pRLw1hkSCjJ=jjDj9ej-Cw@mail.gmail.com>
On Mon, Jul 01, 2013 at 03:35:47PM -0700, Wedson Almeida Filho wrote:
> On Mon, Jul 1, 2013 at 3:28 PM, Borislav Petkov <bp@alien8.de> wrote:
> >
> > perf stat --repeat 10 -a --sync --pre 'make -s clean; echo 1 > /proc/sys/vm/drop_caches' make -s -j64 bzImage
>
> How many CPUs do you have in your system? Maybe -j64 vs -jNUM_CPUs
> affects your measurements as well.
8. But that shouldn't matter since I made the non-differing measurements two
mails back with -j64.
Also -j9, i.e. -j$(($NUM_CPUS+1)) gives "121.613217871 seconds time
elapsed" because with -j9 the probability of some core not executing a
make thread for whatever reason is higher than with -j64. But it is only
as high as an additional 1s with this workload.
I think with -j64 Ingo meant to saturate the scheduler to make sure
there always are runnable threads more than cores available so that we
can maximize the core utilization with threads running our workload.
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--
next prev parent reply other threads:[~2013-07-01 22:44 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-28 10:54 [PATCH] x86: Use asm-goto to implement mutex fast path on x86-64 Wedson Almeida Filho
2013-06-28 11:19 ` Ingo Molnar
2013-06-28 14:09 ` Borislav Petkov
2013-06-28 14:12 ` H. Peter Anvin
2013-06-28 15:15 ` Peter Zijlstra
2013-06-28 16:41 ` [PATCH] x86, cpufeature: Use new CC_HAVE_ASM_GOTO Borislav Petkov
2013-07-05 14:24 ` [tip:x86/cpu] " tip-bot for Borislav Petkov
2013-06-29 23:56 ` [PATCH] x86: Use asm-goto to implement mutex fast path on x86-64 Wedson Almeida Filho
2013-06-30 22:00 ` Borislav Petkov
2013-07-01 7:50 ` Ingo Molnar
2013-07-01 10:23 ` Borislav Petkov
2013-07-01 11:11 ` Ingo Molnar
2013-07-01 12:29 ` Borislav Petkov
2013-07-01 12:50 ` Ingo Molnar
2013-07-01 14:48 ` Borislav Petkov
2013-07-01 22:28 ` Borislav Petkov
2013-07-01 22:35 ` Wedson Almeida Filho
2013-07-01 22:44 ` Borislav Petkov [this message]
2013-07-02 6:39 ` Ingo Molnar
2013-07-02 10:29 ` Borislav Petkov
2013-07-01 14:30 ` H. Peter Anvin
2013-07-01 14:36 ` Borislav Petkov
2013-07-01 14:45 ` H. Peter Anvin
2013-07-01 14:50 ` Borislav Petkov
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20130701224421.GL23515@pd.tnic \
--to=bp@alien8.de \
--cc=a.p.zijlstra@chello.nl \
--cc=akpm@linux-foundation.org \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@kernel.org \
--cc=mingo@redhat.com \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--cc=wedsonaf@gmail.com \
--cc=x86@kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.