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From: William Lee Irwin III <wli@holomorphy.com>
To: Ralf Baechle <ralf@linux-mips.org>
Cc: Theodore Ts'o <tytso@mit.edu>, Andrew Morton <akpm@osdl.org>,
	Anton Blanchard <anton@samba.org>,
	arnd@arndb.de, richm@oldelvet.org.uk, linux-arch@vger.kernel.org
Subject: Re: Using get_cycles for add_timer_randomness
Date: Mon, 16 Aug 2004 09:49:47 -0700	[thread overview]
Message-ID: <20040816164947.GC11200@holomorphy.com> (raw)
In-Reply-To: <20040816164420.GA22312@linux-mips.org>

On Mon, Aug 16, 2004 at 09:22:28AM -0700, William Lee Irwin III wrote:
>> AFAICT most of those return 0 from get_cycles().

On Mon, Aug 16, 2004 at 06:44:20PM +0200, Ralf Baechle wrote:
> The cycle counter on MIPS processors [1] is only 32-bit.  I've been
> pondering to construct a 64-bit value in get_cycles() which would seriously
> slow down the function compared to the current single instruction
> implementation; fortunately a quick survey of all get_cycles() users a
> while ago did look like non of them actually requires the full 64-bit.

What does it return when the 32-bit cycle counter is not present? (It was
not obvious to me; it looks like it returns whatever's in $9.)


-- wli

  reply	other threads:[~2004-08-16 16:50 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <200308160303.17612.arnd@arndb.de>
     [not found] ` <20040810162435.GK24690@krispykreme>
     [not found]   ` <20040814183623.GB5637@krispykreme>
2004-08-15 22:48     ` Using get_cycles for add_timer_randomness Andrew Morton
2004-08-15 23:46       ` Richard Mortimer
2004-08-15 23:59       ` David S. Miller
2004-08-16 16:17       ` Theodore Ts'o
2004-08-16 16:22         ` William Lee Irwin III
2004-08-16 16:44           ` Ralf Baechle
2004-08-16 16:49             ` William Lee Irwin III [this message]
2004-08-19 18:26               ` Ralf Baechle
2004-08-16 18:53 Luck, Tony
  -- strict thread matches above, loose matches on Subject: below --
2004-08-16 21:29 Luck, Tony

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