From: Andi Kleen <ak@suse.de>
To: john stultz <johnstul@us.ibm.com>
Cc: torvalds@transmeta.com, akpm@digeo.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] linux-2.5.66_monotonic-clock_A3
Date: 29 Mar 2003 08:57:14 +0100 [thread overview]
Message-ID: <p73el4qzjtx.fsf@oldwotan.suse.de> (raw)
In-Reply-To: <1048892109.975.150.camel@w-jstultz2.beaverton.ibm.com.suse.lists.linux.kernel>
john stultz <johnstul@us.ibm.com> writes:
> + do {
> + seq = read_seqbegin(&xtime_lock);
> + ret = timer->monotonic_clock();
> + } while (read_seqretry(&xtime_lock, seq));
Why does it need to check xtime lock ? xtime should be independent
of the monotonic time because it can be changed.
Also doing seqlocks around hardware register reads is quite nasty,
because a hardware register read can be hundreds of cycles and you're
very likely to get retries. If you really need a seqlock I would
move it into the low level function and do it after the hardware access.
But as far as I can see it can be just removed.
-Andi
next parent reply other threads:[~2003-03-29 7:45 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1048892109.975.150.camel@w-jstultz2.beaverton.ibm.com.suse.lists.linux.kernel>
2003-03-29 7:57 ` Andi Kleen [this message]
2003-03-31 18:39 ` john stultz
2003-03-28 22:55 john stultz
2003-03-29 0:24 ` john stultz
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