From: Andrea Arcangeli <andrea@suse.de>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>,
linux-kernel@vger.kernel.org, John Stultz <johnstul@us.ibm.com>,
Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [patch, v2.6.22-rc6] sys_time() speedup
Date: Wed, 27 Jun 2007 02:22:08 +0200 [thread overview]
Message-ID: <20070627002208.GB6670@v2.random> (raw)
In-Reply-To: <20070626101440.8f9ab65b.akpm@linux-foundation.org>
On Tue, Jun 26, 2007 at 10:14:40AM -0700, Andrew Morton wrote:
> On my machine, time(2) doesn't do any syscall at all - it uses the vsyscall
> page. I'd be surprised if a database uses sys_time() either.
Large boxes unfortunately can't always use vsyscalls... that's a real
pity. I also had to disable the vsyscalls64 to generate some number.
I think there shall be a perfectly accurate but not monotone mode for
gettimeofday so we can enable rdtscp (via sysctl or/and prctl). Aware
apps can enable the prctl, aware or brave admins can turn on the
sysctl. Vojtech and others should have proper patches to merge for
this.
next prev parent reply other threads:[~2007-06-27 0:22 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-06-25 20:06 [patch, v2.6.22-rc6] sys_time() speedup Ingo Molnar
2007-06-25 21:09 ` Roman Zippel
2007-06-25 21:17 ` Jesper Juhl
2007-06-25 22:00 ` Roman Zippel
2007-06-25 22:20 ` Jesper Juhl
2007-06-25 22:49 ` Roman Zippel
2007-06-26 16:18 ` Ingo Molnar
2007-06-26 16:39 ` Roman Zippel
2007-06-26 16:49 ` Andrea Arcangeli
2007-06-26 17:13 ` Ray Lee
2007-06-27 0:15 ` Andrea Arcangeli
2007-06-26 17:08 ` Roman Zippel
2007-06-26 17:35 ` Andrew Morton
2007-06-25 22:15 ` Andrew Morton
2007-06-26 2:20 ` Stephen Rothwell
2007-06-26 15:26 ` Ingo Molnar
2007-06-26 17:14 ` Andrew Morton
2007-06-27 0:22 ` Andrea Arcangeli [this message]
2007-06-26 15:43 ` Andrea Arcangeli
2007-06-26 17:36 ` Andrew Morton
2007-06-25 22:02 ` Eric Dumazet
2007-06-26 0:22 ` Mark Lord
2007-06-26 14:58 ` Ingo Molnar
2007-06-26 16:59 ` john stultz
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