From: john stultz <johnstul@us.ibm.com>
To: Richard Cochran <richardcochran@gmail.com>
Cc: Andy Lutomirski <luto@amacapital.net>,
linux-kernel@vger.kernel.org, Kumar Sundararajan <kumar@fb.com>,
Arun Sharma <asharma@fb.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>
Subject: Re: [RFC 0/2] ABI for clock_gettime_ns
Date: Mon, 12 Dec 2011 19:43:02 -0800 [thread overview]
Message-ID: <1323747782.4078.144.camel@work-vm> (raw)
In-Reply-To: <20111213032406.GA9604@netboy.at.omicron.at>
On Tue, 2011-12-13 at 04:24 +0100, Richard Cochran wrote:
> On Mon, Dec 12, 2011 at 05:26:36PM -0800, Andy Lutomirski wrote:
> > On x86-64, clock_gettime is so fast that the overhead converting to and
> > from nanoseconds is non-negligible. clock_gettime_ns is a different
> > interface that is potentially faster. If people like the ABI, I'll
> > implement an optimized version.
>
> I am not so interested in performance optimizations, but do I think
> offering time in nanoseconds is attractive from an application point
> of view. The timespec is impractical for everyone.
>
> While you are at it with new syscalls, why not make a clean break from
> POSIX and fix the uglies?
>
> - New name, to distance ourselves from POSIX (clock_ns_get?)
> - Family of calls, with set/get
> - Sub nanosecond field
> - TAI time base (or according to parameter?)
Having a CLOCK_TAI would be interesting across the board. We already
keep a TAI offset in the ntp code. However, I'm not sure if ntp actually
sets it these days.
thanks
-john
next prev parent reply other threads:[~2011-12-13 3:43 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-13 1:26 [RFC 0/2] ABI for clock_gettime_ns Andy Lutomirski
2011-12-13 1:26 ` [RFC 1/2] Add clock_gettime_ns syscall Andy Lutomirski
2011-12-13 3:32 ` Richard Cochran
2011-12-13 1:26 ` [RFC 2/2] x86-64: Add __vdso_clock_gettime_ns vsyscall Andy Lutomirski
2011-12-13 3:24 ` [RFC 0/2] ABI for clock_gettime_ns Richard Cochran
2011-12-13 3:43 ` john stultz [this message]
2011-12-13 7:09 ` Andy Lutomirski
2011-12-14 7:46 ` Richard Cochran
2011-12-14 16:48 ` john stultz
2011-12-14 17:15 ` Andy Lutomirski
2011-12-14 17:31 ` john stultz
2011-12-14 18:37 ` Richard Cochran
2011-12-14 18:30 ` Richard Cochran
2011-12-14 19:07 ` john stultz
2011-12-14 19:20 ` Andy Lutomirski
2011-12-14 21:34 ` john stultz
2011-12-15 11:35 ` Richard Cochran
2011-12-22 12:03 ` Richard Cochran
2011-12-24 5:59 ` Andy Lutomirski
2011-12-24 6:50 ` Richard Cochran
2011-12-25 4:06 ` Andy Lutomirski
2011-12-14 7:20 ` Richard Cochran
2011-12-14 16:23 ` john stultz
2011-12-14 18:21 ` Richard Cochran
2011-12-14 18:57 ` john stultz
2012-01-07 19:51 ` Richard Cochran
2011-12-21 0:50 ` Arun Sharma
2011-12-21 1:07 ` Andy Lutomirski
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