From: David Miller <davem@davemloft.net>
To: carlos@systemhalted.org
Cc: drow@false.org, joseph@codesourcery.com, schwab@linux-m68k.org,
thomas_schwinge@mentor.com, kkojima@rr.iij4u.or.jp,
marcus.shawcroft@linaro.org, katsuki.uwatoko@toshiba.co.jp,
libc-ports@sourceware.org
Subject: Re: [PATCH] Avoid unnecessary busy loop in __lll_timedlock_wait on ARM.
Date: Sat, 09 Feb 2013 06:49:00 -0000 [thread overview]
Message-ID: <20130209.014909.573423212502453699.davem@davemloft.net> (raw)
In-Reply-To: <CAE2sS1isYziYbmy1sgvhVPTp8_3hbNYKsnj_pXrZmjv53=mm6Q@mail.gmail.com>
From: "Carlos O'Donell" <carlos@systemhalted.org>
Date: Fri, 8 Feb 2013 23:18:42 -0500
> I see that sparc32 also has a unique copy of lowlevellock.c Why the
> use of *_24_* atomic primitives? Faster?
On pre-v9 32-bit sparc, we lack any usable atomic compare and
swap.
All we have is an 8-bit spinlock.
So we implement things in a 32-bit word which is composed of a 24-bit
counter and an 8-bit lock.
next prev parent reply other threads:[~2013-02-09 6:49 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-31 8:42 katsuki.uwatoko
2013-02-07 23:33 ` Joseph S. Myers
2013-02-08 0:13 ` katsuki.uwatoko
2013-02-09 4:18 ` Carlos O'Donell
2013-02-09 6:49 ` David Miller [this message]
2013-02-09 14:56 ` Carlos O'Donell
2013-02-10 4:56 ` David Miller
2013-02-10 17:55 ` Carlos O'Donell
2013-02-12 21:41 ` Daniel Jacobowitz
2013-02-12 21:41 ` Daniel Jacobowitz
2013-02-12 21:57 ` Carlos O'Donell
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