From mboxrd@z Thu Jan  1 00:00:00 1970
From: Timur Tabi <timur@tabi.org>
Subject: Re: [PATCH 2/2] Convert PowerPC macro spin_event_timeout() to
 architecture independent macro
Date: Wed, 31 Jul 2013 23:43:18 -0500
Message-ID: <51F9E766.604@tabi.org>
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To: Goel Arpit-B44344 <B44344@freescale.com>
Cc: "linux-m32r-ja@ml.linux-m32r.org" <linux-m32r-ja@ml.linux-m32r.org>, "linux-m68k@vger.kernel.org" <linux-m68k@vger.kernel.org>, "heiko.carstens@de.ibm.com" <heiko.carstens@de.ibm.com>, "sparclinux@vger.kernel.org" <sparclinux@vger.kernel.org>, "sam@ravnborg.org" <sam@ravnborg.org>, "linux-s390@vger.kernel.org" <linux-s390@vger.kernel.org>, "jesper.nilsson@axis.com" <jesper.nilsson@axis.com>, "linux@arm.linux.org.uk" <linux@arm.linux.org.uk>, "takata@linux-m32r.org" <takata@linux-m32r.org>, Geert Uytterhoeven <geert@linux-m68k.org>, Arnd Bergmann <arnd@arndb.de>, Rob Herring <rob.herring@calxeda.com>, "john.stultz@linaro.org" <john.stultz@linaro.org>, Stephen Warren <swarren@nvidia.com>, "linux-arm-kernel@lists.infradead.org" <linux-arm-kernel@lists.infradead.org>, "linux-m32r@ml.linux-m32r.org" <linux-m32r@ml.linux-m32r.org>, "gregkh@linuxfoundation.org" <gregkh@linuxf>
List-Id: linux-m68k@vger.kernel.org

Goel Arpit-B44344 wrote:
> PowerPC uses hardware timer registers provided by PowerPC architecture to implement spin_event_timeout(). These registers make
> PowerPC implementation of spin_event_timeout() more granular in comparison to ones using generic USECS_PER_JIFFY framework. This
> would handle those cases more granularly in which evaluation of "condition" is taking time or fails.

LOL, it seems I forgot how my own code works.  Thanks for the reminder. 
  For some reason, I thought the PowerPC version was also using 
'jiffies'.  The concern about using 'jiffies' makes a lot more sense now.

Almost every architecture has a timebase counter.  Wouldn't it make more 
sense to port tb_ticks_per_usec, get_tbl(), and tb_ticks_since() to 
other architectures instead?  I don't think 'jiffies' is granular enough 
for spin_event_timeout().