From: Jim Rees <rees@umich.edu>
To: "Patrick J. LoPresti" <lopresti@gmail.com>
Cc: john stultz <johnstul@us.ibm.com>, linux-nfs@vger.kernel.org
Subject: Re: Proposal: Use hi-res clock for file timestamps
Date: Fri, 13 Aug 2010 15:57:14 -0400 [thread overview]
Message-ID: <20100813195714.GB12061@merit.edu> (raw)
In-Reply-To: <AANLkTin-dksybH0ANypheovXXubwd+SRCpurdVRU7-Z=@mail.gmail.com>
Patrick J. LoPresti wrote:
On Fri, Aug 13, 2010 at 11:45 AM, john stultz <johnstul@us.ibm.com> wrote:
> On those TSC broken systems that use the hpet or acpi_pm, a
> getnstimeofday call can take 0.5-1.3us, so the penalty can be quite
> severe.
So you are saying my proposal is a bad idea forever? (But then why
even bother having nanosecond resolution on ext4?)
How about using getnstimeofday() only if the kernel clocksource is tsc?
Presumably anyone running into this problem would have modern high
performance hardware with working tsc.
next prev parent reply other threads:[~2010-08-13 19:57 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-13 18:25 Proposal: Use hi-res clock for file timestamps Patrick J. LoPresti
2010-08-13 18:45 ` john stultz
2010-08-13 18:57 ` Patrick J. LoPresti
2010-08-13 19:09 ` john stultz
2010-08-13 20:53 ` Patrick J. LoPresti
2010-08-14 16:45 ` Patrick J. LoPresti
2010-08-15 1:50 ` Bret Towe
2010-08-13 19:57 ` Jim Rees [this message]
2010-08-13 20:26 ` john stultz
2010-08-13 20:52 ` Jim Rees
2010-08-17 14:54 ` Andi Kleen
2010-08-17 17:41 ` J. Bruce Fields
2010-08-17 18:29 ` Andi Kleen
2010-08-17 18:50 ` Patrick J. LoPresti
2010-08-17 19:04 ` J. Bruce Fields
2010-08-17 19:18 ` Patrick J. LoPresti
2010-08-17 19:39 ` Alan Cox
2010-08-17 19:29 ` J. Bruce Fields
2010-08-17 19:52 ` Alan Cox
2010-08-18 5:53 ` Neil Brown
2010-08-18 14:46 ` Patrick J. LoPresti
2010-08-18 17:32 ` J. Bruce Fields
2010-08-18 18:15 ` Chuck Lever
2010-08-18 23:41 ` Neil Brown
2010-08-19 0:52 ` Neil Brown
2010-08-19 2:08 ` J. Bruce Fields
2010-08-19 2:44 ` Neil Brown
2010-08-19 22:46 ` J. Bruce Fields
2010-08-18 23:47 ` Neil Brown
2010-08-18 17:50 ` Andi Kleen
2010-08-18 18:54 ` J. Bruce Fields
2010-08-18 19:25 ` Andi Kleen
2010-08-18 19:30 ` J. Bruce Fields
2010-08-17 19:34 ` Patrick J. LoPresti
2010-08-17 19:54 ` Alan Cox
2010-08-17 19:43 ` Patrick J. LoPresti
2010-08-17 19:45 ` J. Bruce Fields
2010-08-18 18:12 ` J. Bruce Fields
2010-08-19 1:41 ` john stultz
2010-08-19 2:31 ` J. Bruce Fields
2010-08-19 3:17 ` john stultz
2010-08-19 22:53 ` J. Bruce Fields
2010-08-18 18:20 ` David Woodhouse
2010-08-18 18:32 ` Patrick J. LoPresti
2010-08-18 18:53 ` Andi Kleen
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