From: john stultz <johnstul@us.ibm.com>
To: Arun Sharma <asharma@fb.com>
Cc: linux-kernel@vger.kernel.org, Kumar Sundararajan <kumar@fb.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@elte.hu>, Thomas Gleixner <tglx@linutronix.de>,
Andy Lutomirski <luto@MIT.EDU>
Subject: Re: [PATCH 2/2] Add a thread cpu time implementation to vDSO
Date: Mon, 12 Dec 2011 15:09:21 -0800 [thread overview]
Message-ID: <1323731361.4078.102.camel@work-vm> (raw)
In-Reply-To: <1323718578-1157-3-git-send-email-asharma@fb.com>
On Mon, 2011-12-12 at 11:36 -0800, Arun Sharma wrote:
> From: Kumar Sundararajan <kumar@fb.com>
>
> This primarily speeds up clock_gettime(CLOCK_THREAD_CPUTIME_ID, ..)
> via a new vsyscall. We also add a direct vsyscall that returns
> time in ns (RFC: the direct vsyscall doesn't have a corresponding
> regular syscall, although clock_gettime() is pretty close).
I'm still not super psyched about providing a vdso-only API.
If a nanosecond interface like thread_cpu_time() is actually a big win
over clock_gettime(CLOCK_THREAD_CPUTIME,...) it seems it should have its
own syscall as well, no?
Possibly something like clock_gettime_ns(), which would return the same
values as clock_gettime() but in nanoseconds rather then a timespec?
thanks
-john
next prev parent reply other threads:[~2011-12-12 23:09 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-12 19:36 [PATCH 0/2] Add a thread cpu time implementation to vDSO Arun Sharma
2011-12-12 19:36 ` [PATCH 1/2] Extend VVAR support to multiple pages Arun Sharma
2011-12-12 19:36 ` [PATCH 2/2] Add a thread cpu time implementation to vDSO Arun Sharma
2011-12-12 20:13 ` Eric Dumazet
2011-12-12 21:19 ` Arun Sharma
2011-12-12 21:27 ` Eric Dumazet
2011-12-12 21:33 ` Andrew Lutomirski
2011-12-12 22:14 ` Arun Sharma
2011-12-13 8:52 ` Peter Zijlstra
2011-12-13 18:15 ` Arun Sharma
2011-12-13 18:53 ` Peter Zijlstra
2011-12-12 20:15 ` Andrew Lutomirski
2011-12-12 22:49 ` Arun Sharma
2011-12-12 23:01 ` Andrew Lutomirski
2011-12-13 0:40 ` Arun Sharma
2011-12-12 23:09 ` john stultz [this message]
2011-12-12 23:20 ` Arun Sharma
2011-12-12 23:32 ` john stultz
2011-12-12 23:41 ` Andrew Lutomirski
2011-12-12 23:52 ` john stultz
2011-12-13 0:26 ` Arun Sharma
-- strict thread matches above, loose matches on Subject: below --
2011-12-19 19:51 [PATCH 0/2] Add a thread cpu time implementation to vDSO (v2) Arun Sharma
2011-12-19 19:51 ` [PATCH 2/2] Add a thread cpu time implementation to vDSO Arun Sharma
2011-12-19 19:58 ` Arun Sharma
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