From: Clemens Ladisch <clemens@ladisch.de>
To: David Brownell <david-b@pacbell.net>
Cc: lkml <linux-kernel@vger.kernel.org>,
bob.picco@hp.com, venkatesh.pallipadi@intel.com,
Vojtech Pavlik <vojtech@suse.cz>,
the arch/x86 maintainers <x86@kernel.org>
Subject: Re: [patch 2.6.26] /dev/hpet - fixes and cleanup
Date: Thu, 24 Jul 2008 13:35:57 +0200 [thread overview]
Message-ID: <4888691D.5090307@ladisch.de> (raw)
In-Reply-To: <200807230912.49850.david-b@pacbell.net>
David Brownell wrote:
> I didn't find any software using /dev/hpet, except for
> the example in Documentation/hpet.txt ... presumably I
> was looking in the wrong place. I'd surely have retched
> at anything mmapping hardware registers though. ;)
http://subversion.jackaudio.org/jack/trunk/jack/config/os/gnu-linux/time.c
> > This seems to be the only part of the userspace interface that is
> > used in practice. Because of the availability of POSIX timers, it might
> > make sense to deprecate the HPET ioctl interface.
>
> I'll leave that part up to someone else. If POSIX timers
> are a sufficient userspace interface, great ... then that
> mmap son't really be needed either!
The idea is to be able to get a high-precision timer value without doing
a syscall. (Whether the syscall overhead actually matters in a specific
application is another question.)
Regards,
Clemens
next prev parent reply other threads:[~2008-07-24 11:36 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-22 22:08 [patch 2.6.26] /dev/hpet - fixes and cleanup David Brownell
2008-07-23 7:44 ` Clemens Ladisch
2008-07-23 16:12 ` David Brownell
2008-07-23 16:50 ` David Brownell
2008-07-24 11:35 ` Clemens Ladisch [this message]
2008-07-25 19:55 ` David Brownell
2008-07-29 21:26 ` H. Peter Anvin
2008-07-25 19:58 ` [patch 2.6.26-git] " David Brownell
2008-07-28 7:57 ` Clemens Ladisch
2008-07-28 8:27 ` David Brownell
2008-07-28 9:10 ` Clemens Ladisch
2008-07-29 19:46 ` David Brownell
2008-07-29 19:47 ` [patch 2.6.27-rc1] " David Brownell
2008-07-31 16:46 ` Ingo Molnar
2008-07-31 16:55 ` Ingo Molnar
2008-07-31 19:59 ` David Brownell
2008-07-31 20:50 ` Ingo Molnar
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