From: Jonas Oreland <jonas@mysql.com>
To: Ray Bryant <raybry@mpdtxmail.amd.com>
Cc: Andi Kleen <ak@suse.de>, Daniel Jacobowitz <dan@debian.org>,
john stultz <johnstul@us.ibm.com>, Andrew Morton <akpm@osdl.org>,
lkml <linux-kernel@vger.kernel.org>,
discuss@x86-64.org
Subject: Re: [discuss] Re: [PATCH] x86-64: Fix bad assumption that dualcore cpus have synced TSCs
Date: Thu, 22 Sep 2005 10:00:47 +0200 [thread overview]
Message-ID: <433264AF.5060800@mysql.com> (raw)
In-Reply-To: <200509211046.25555.raybry@mpdtxmail.amd.com>
Ray Bryant wrote:
> On Wednesday 21 September 2005 10:04, Andi Kleen wrote:
>
>
>>We handle this, but single socket dual core was special cased because
>>I was told previously it should be ok.
>>
>>-Andi
>
>
> AFAIK there is a processor state bit that enables/disables this behavior.
> Apparently some BIOS's are setting this one way for desktop systems and the
> other way for servers. If it is thought to be important I can track that
> down and see if it can be externally documented. (It may actually be in the
> bios and kernel developer guide...)
>
Hi,
This would be very good (for us single socket dual core users)
I tried a very small benchmark:
clock_gettime(CLOCK_REALTIME): elapsed 7336657 -> 733.665700ns/call
clock_gettime(CLOCK_PROCESS_CPUTIME_ID): elapsed 763247 -> 76.324700ns/call
It's a factor 10 faster if the TSC were to be in sync.
/Jonas
next prev parent reply other threads:[~2005-09-22 7:57 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-19 19:16 [PATCH] x86-64: Fix bad assumption that dualcore cpus have synced TSCs john stultz
2005-09-19 19:31 ` Andi Kleen
2005-09-19 19:42 ` john stultz
2005-09-19 19:49 ` [discuss] " Andi Kleen
2005-09-20 18:59 ` john stultz
2005-09-21 4:03 ` Daniel Jacobowitz
2005-09-21 15:15 ` Ray Bryant
2005-09-21 15:04 ` Andi Kleen
2005-09-21 15:46 ` Ray Bryant
2005-09-22 8:00 ` Jonas Oreland [this message]
2005-09-21 20:17 ` Andrew Morton
2005-10-07 12:26 ` Vladimir B. Savkin
2005-10-07 12:31 ` Andi Kleen
2005-10-07 14:15 ` Vladimir B. Savkin
2005-10-07 14:21 ` [discuss] " Velu Erwan
2005-10-08 10:11 ` Vladimir B. Savkin
2005-10-10 18:03 ` john stultz
2005-10-10 18:12 ` Vladimir B. Savkin
2005-10-10 18:19 ` Jonas Oreland
2005-10-11 7:35 ` Vladimir B. Savkin
2005-10-11 8:06 ` Andi Kleen
2005-10-11 16:27 ` Jonas Oreland
2005-10-25 7:35 ` x86-64: Syncing dualcore cpus TSCs Jonas Oreland
2005-10-25 7:42 ` Andi Kleen
2005-10-26 0:05 ` David Lang
-- strict thread matches above, loose matches on Subject: below --
2005-09-20 19:13 [discuss] Re: [PATCH] x86-64: Fix bad assumption that dualcore cpus have synced TSCs Langsdorf, Mark
2005-09-20 19:24 ` Scott Lampert
2005-09-20 19:30 ` john stultz
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=433264AF.5060800@mysql.com \
--to=jonas@mysql.com \
--cc=ak@suse.de \
--cc=akpm@osdl.org \
--cc=dan@debian.org \
--cc=discuss@x86-64.org \
--cc=johnstul@us.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=raybry@mpdtxmail.amd.com \
/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.