From: "Martin J. Bligh" <Martin.Bligh@us.ibm.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Pavel Machek <pavel@elf.ucw.cz>,
Andrea Arcangeli <andrea@suse.de>,
Mikael Pettersson <mikpe@csd.uu.se>,
john stultz <johnstul@us.ibm.com>,
Marcelo Tosatti <marcelo@conectiva.com.br>,
lkml <linux-kernel@vger.kernel.org>,
Leah Cunningham <leahc@us.ibm.com>,
wilhelm.nuesser@sap.com, paramjit@us.ibm.com, msw@redhat.com
Subject: Re: [PATCH] tsc-disable_B9
Date: Mon, 26 Aug 2002 13:19:24 -0700 [thread overview]
Message-ID: <160380000.1030393164@flay> (raw)
In-Reply-To: <1030388713.2776.11.camel@irongate.swansea.linux.org.uk>
>> It's not correlating it to real time that's the problem. It's getting resceduled
>> inbetween calls that hurts. Take your example.
>>
>> rdtsc
>> mov %eax,%ebx
>> <- get rescheduled here
>> rdtsc
>>
>> Broken. May even take negative "time".
>
> Statistically irrelevant. When you have 100,000 samples all the
> pre-emption ones drop into the dud sample filter with IRQ disturbance
> and so on.
OK, so let's take a better example. People are (I think) mainly using rdtsc
to provide a monotonically increasing counter for database "transaction
order" stamping. I think that's really the case we're worried about.
M.
next prev parent reply other threads:[~2002-08-26 20:20 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-08-08 1:53 [PATCH] tsc-disable_B9 john stultz
2002-08-08 2:15 ` [PATCH] cyclone-timer_A9 john stultz
2002-08-08 13:18 ` Alan Cox
2002-08-09 2:03 ` john stultz
2002-08-08 13:17 ` [PATCH] tsc-disable_B9 Alan Cox
2002-08-09 2:30 ` john stultz
2002-08-09 9:17 ` Alan Cox
2002-08-09 17:46 ` john stultz
2002-08-09 18:49 ` george anzinger
2002-08-09 20:58 ` john stultz
2002-08-13 1:23 ` James Cleverdon
2002-08-11 20:16 ` Alan Cox
2002-08-15 16:56 ` Andrea Arcangeli
2002-08-16 11:15 ` Alan Cox
2002-08-16 13:19 ` Mikael Pettersson
2002-08-21 13:12 ` Andrea Arcangeli
2002-08-21 14:10 ` Alan Cox
2002-08-21 14:33 ` Andrea Arcangeli
2002-08-21 15:01 ` Alan Cox
2002-08-21 16:13 ` Andrea Arcangeli
2002-08-21 16:25 ` Alan Cox
2002-08-21 17:17 ` Andrea Arcangeli
2002-08-21 17:34 ` Alan Cox
2002-08-26 16:10 ` Pavel Machek
2002-08-26 18:45 ` Martin J. Bligh
2002-08-26 19:00 ` Pavel Machek
2002-08-26 19:05 ` Alan Cox
2002-08-26 20:19 ` Martin J. Bligh [this message]
2002-08-26 19:18 ` Richard B. Johnson
2002-08-26 19:42 ` Pavel Machek
2002-08-26 20:23 ` Alan Cox
2002-08-26 22:49 ` Andrea Arcangeli
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=160380000.1030393164@flay \
--to=martin.bligh@us.ibm.com \
--cc=alan@lxorguk.ukuu.org.uk \
--cc=andrea@suse.de \
--cc=johnstul@us.ibm.com \
--cc=leahc@us.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=marcelo@conectiva.com.br \
--cc=mikpe@csd.uu.se \
--cc=msw@redhat.com \
--cc=paramjit@us.ibm.com \
--cc=pavel@elf.ucw.cz \
--cc=wilhelm.nuesser@sap.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.