From: Andi Kleen <ak@suse.de>
To: Ingo Molnar <mingo@elte.hu>
Cc: jbohac@suse.cz, linux-kernel@vger.kernel.org,
Vojtech Pavlik <vojtech@suse.cz>,
arjan@infradead.org, tglx@linutronix.de, johnstul@us.ibm.com,
Andrew Morton <akpm@osdl.org>
Subject: Re: [-mm patch] x86_64 GTOD: offer scalable vgettimeofday
Date: Thu, 1 Feb 2007 13:01:51 +0100 [thread overview]
Message-ID: <200702011301.51834.ak@suse.de> (raw)
In-Reply-To: <20070201114644.GB26453@elte.hu>
On Thursday 01 February 2007 12:46, Ingo Molnar wrote:
>
> * jbohac@suse.cz <jbohac@suse.cz> wrote:
>
> > Inter-CPU monotonicity can not, however, be guaranteed in a vsyscall,
> > so vsyscall is not used by default. [...]
>
> note that this is not actually the case. My patch below, ontop of -mm,
> implements a fully monotonic gettimeofday as an optional vsyscall
> feature.
>
> The 'price' paid for it is lower resolution - but it's still good for
> those benchmarking TPC-C runs - and /alot/ simpler. It's also quite a
> bit faster than any TSC based vgettimeofday, because it doesnt have to
> do an RDTSC (or RDTSCP) instruction nor any approximation of the time.
I believe that should be also a separate clock_gettime() CLOCK_
Global settings for these things are bad. Even if you run TPC-C you don't
want your other programs that rely on monotonic time to break.
-Andi
next prev parent reply other threads:[~2007-02-01 12:02 UTC|newest]
Thread overview: 68+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-02-01 9:59 [patch 0/9] x86_64: reliable TSC-based gettimeofday jbohac
2007-02-01 9:59 ` [patch 1/9] Fix HPET init race jbohac
2007-02-02 2:34 ` Andrew Morton
2007-02-06 16:44 ` Jiri Bohac
2007-02-07 0:12 ` Andrew Morton
2007-02-10 12:31 ` Andi Kleen
2007-07-26 20:58 ` Robin Holt
2007-02-01 9:59 ` [patch 2/9] Remove the support for the VXTIME_PMTMR timer mode jbohac
2007-02-01 11:13 ` Andi Kleen
2007-02-01 13:13 ` Jiri Bohac
2007-02-01 13:13 ` Andi Kleen
2007-02-01 13:59 ` Jiri Bohac
2007-02-01 14:18 ` Andi Kleen
2007-02-01 9:59 ` [patch 3/9] Remove the support for the VXTIME_HPET " jbohac
2007-02-01 9:59 ` [patch 4/9] Remove the TSC synchronization on SMP machines jbohac
2007-02-01 11:14 ` Andi Kleen
2007-02-01 13:17 ` Jiri Bohac
2007-02-01 15:16 ` Vojtech Pavlik
2007-02-02 7:14 ` Andi Kleen
2007-02-13 0:34 ` Christoph Lameter
2007-02-13 6:40 ` Arjan van de Ven
2007-02-13 8:28 ` Andi Kleen
2007-02-13 8:41 ` Arjan van de Ven
2007-02-13 17:09 ` Christoph Lameter
2007-02-13 17:20 ` Andi Kleen
2007-02-13 22:18 ` Vojtech Pavlik
2007-02-13 22:38 ` Andrea Arcangeli
2007-02-14 6:59 ` Vojtech Pavlik
2007-02-13 23:55 ` Christoph Lameter
2007-02-14 0:18 ` Paul Mackerras
2007-02-14 0:25 ` john stultz
2007-02-02 7:13 ` Andi Kleen
2007-02-01 21:05 ` mbligh
2007-02-03 1:16 ` H. Peter Anvin
2007-02-01 9:59 ` [patch 5/9] Add all the necessary structures to the vsyscall page jbohac
2007-02-01 11:17 ` Andi Kleen
2007-02-01 9:59 ` [patch 6/9] Add the "Master Timer" jbohac
2007-02-01 11:22 ` Andi Kleen
2007-02-01 13:29 ` Jiri Bohac
2007-02-01 9:59 ` [patch 7/9] Adapt the time initialization code jbohac
2007-02-01 11:26 ` Andi Kleen
2007-02-01 13:41 ` Jiri Bohac
2007-02-01 10:00 ` [patch 8/9] Add time_update_mt_guess() jbohac
2007-02-01 11:28 ` Andi Kleen
2007-02-01 13:54 ` Jiri Bohac
2007-02-01 10:00 ` [patch 9/9] Make use of the Master Timer jbohac
2007-02-01 11:36 ` Andi Kleen
2007-02-01 14:29 ` Jiri Bohac
2007-02-01 15:23 ` Vojtech Pavlik
2007-02-02 7:05 ` Andi Kleen
2007-02-02 7:04 ` Andi Kleen
2007-02-01 11:20 ` [patch 0/9] x86_64: reliable TSC-based gettimeofday Andi Kleen
2007-02-01 11:53 ` Andrea Arcangeli
2007-02-01 12:02 ` Andi Kleen
2007-02-01 12:54 ` Andrea Arcangeli
2007-02-01 12:17 ` Ingo Molnar
2007-02-01 14:52 ` Jiri Bohac
2007-02-01 16:56 ` john stultz
2007-02-01 19:41 ` Vojtech Pavlik
2007-02-01 11:34 ` Ingo Molnar
2007-02-01 11:46 ` [-mm patch] x86_64 GTOD: offer scalable vgettimeofday Ingo Molnar
2007-02-01 12:01 ` Andi Kleen [this message]
2007-02-01 12:14 ` Ingo Molnar
2007-02-01 12:17 ` [-mm patch] x86_64 GTOD: offer scalable vgettimeofday II Andi Kleen
2007-02-01 12:24 ` Ingo Molnar
2007-02-01 12:45 ` Andi Kleen
2007-02-02 4:22 ` [patch 0/9] x86_64: reliable TSC-based gettimeofday Andrew Morton
2007-02-02 7:07 ` Andi Kleen
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=200702011301.51834.ak@suse.de \
--to=ak@suse.de \
--cc=akpm@osdl.org \
--cc=arjan@infradead.org \
--cc=jbohac@suse.cz \
--cc=johnstul@us.ibm.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=tglx@linutronix.de \
--cc=vojtech@suse.cz \
/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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).