From: Lee Revell <rlrevell@joe-job.com>
To: john stultz <johnstul@us.ibm.com>
Cc: Roman Zippel <zippel@linux-m68k.org>,
lkml <linux-kernel@vger.kernel.org>,
Andrew Morton <akpm@osdl.org>,
George Anzinger <george@mvista.com>,
Ulrich Windl <ulrich.windl@rz.uni-regensburg.de>
Subject: Re: [PATCH 1/6] new timeofday core subsystem for -mm (v.B3)
Date: Mon, 20 Jun 2005 19:44:56 -0400 [thread overview]
Message-ID: <1119311096.17701.3.camel@mindpipe> (raw)
In-Reply-To: <1119304422.9947.90.camel@cog.beaverton.ibm.com>
On Mon, 2005-06-20 at 14:53 -0700, john stultz wrote:
> Yea, honestly I doubt gettimefoday performance will ever be as good as
> rdtsc. I mean, that's a single instruction vs syscall overhead +
> hardware clock reading + frequency conversion + ntp adjustment. Its
> just not a fair comparison.
Of course not, the patch would have to be magic for that to happen.
But some user space apps are now *required* to use rdtsc for timing due
to the massive performance difference. If we only took a 5x or 10x
performance hit vs rdtsc, rather than the current 50x, it might be
enough that user space apps won't have to do this.
Lee
next prev parent reply other threads:[~2005-06-21 0:05 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-06-18 2:56 [PATCH 1/6] new timeofday core subsystem for -mm (v.B3) john stultz
2005-06-18 2:58 ` [PATCH 2/6] new timeofday i386 arch specific changes, part 1 " john stultz
2005-06-18 2:59 ` [PATCH 3/6] new timeofday i386 arch specific changes, part 2 " john stultz
2005-06-18 3:01 ` [PATCH 4/6] new timeofday i386 arch specific changes, part 3 " john stultz
2005-06-18 3:02 ` [PATCH 5/6] new timeofday i386 arch specific changes, part 4 " john stultz
2005-06-18 3:04 ` [PATCH 6/6] new timeofday i386 specific timesources " john stultz
2005-06-18 12:02 ` [PATCH 1/6] new timeofday core subsystem " Roman Zippel
2005-06-20 7:01 ` Ulrich Windl
2005-06-20 10:22 ` Roman Zippel
2005-06-20 10:31 ` Ulrich Windl
2005-06-20 10:54 ` Roman Zippel
2005-06-20 11:04 ` Christoph Hellwig
2005-06-20 17:09 ` john stultz
2005-06-20 18:10 ` Lee Revell
2005-06-20 21:53 ` john stultz
2005-06-20 23:44 ` Lee Revell [this message]
2005-06-21 14:55 ` Chris Friesen
2005-06-21 17:20 ` john stultz
2005-06-21 6:26 ` Ulrich Windl
2005-06-20 22:05 ` Roman Zippel
2005-06-20 23:40 ` Lee Revell
2005-06-20 23:55 ` john stultz
2005-06-21 15:08 ` Roman Zippel
2005-06-22 0:57 ` john stultz
2005-06-22 2:39 ` john stultz
2005-06-22 19:45 ` Roman Zippel
2005-06-23 0:29 ` john stultz
2005-06-23 21:59 ` Roman Zippel
2005-06-24 0:33 ` john stultz
2005-06-24 10:58 ` Roman Zippel
2005-06-21 6:42 ` Ulrich Windl
2005-06-21 15:13 ` Roman Zippel
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