From: David Brownell <david-b@pacbell.net>
To: Clemens Ladisch <clemens@ladisch.de>
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: Fri, 25 Jul 2008 12:55:35 -0700 [thread overview]
Message-ID: <200807251255.35675.david-b@pacbell.net> (raw)
In-Reply-To: <4888691D.5090307@ladisch.de>
On Thursday 24 July 2008, Clemens Ladisch wrote:
> David Brownell wrote:
> > > 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.)
On x86_64 the vsyscall stuff should kick in for gettimeofday()
when HPET is in use, eliminating the need for /dev/hpet mmapping.
I don't really know vsyscalls ... but if that could be done on
i386 systems, the last argument for /dev/hpet would seem gone...
next prev parent reply other threads:[~2008-07-25 19:55 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
2008-07-25 19:55 ` David Brownell [this message]
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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