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 14:10:33 -0400 [thread overview]
Message-ID: <1119291034.16180.9.camel@mindpipe> (raw)
In-Reply-To: <1119287354.9947.22.camel@cog.beaverton.ibm.com>
On Mon, 2005-06-20 at 10:09 -0700, john stultz wrote:
> As for gettimefoday() syscall performance, I one had some numbers, but
> I
> would need to re-create them. I'll see if I can grab a slower box and
> give you some hard numbers.
I ran some tests lately that showed gettimeofday() to be 50x slower than
rdtsc() on my 600Mhz machine. Many userspace apps that need a cheap
high res timer have to use rdtsc now due to the excessive overhead of
gettimeofday(). It would be more correct if these apps could use
gettimeofday() for various reasons (cpufreq and SMP issues).
So this patch is addressing a real problem. I'd be interested to see if
the performance is good enough to replace rdtsc in these cases.
Lee
next prev parent reply other threads:[~2005-06-20 18:07 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 [this message]
2005-06-20 21:53 ` john stultz
2005-06-20 23:44 ` Lee Revell
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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