From: Afzal Mohammed <afzal.mohd.ma@gmail.com>
To: yalin wang <yalin.wang2010@gmail.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>,
adaplas@gmail.com, plagnioj@jcrosoft.com,
linux-fbdev@vger.kernel.org,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] fbdev/riva:change to use generice function to implement reverse_order()
Date: Mon, 24 Aug 2015 13:53:48 +0000 [thread overview]
Message-ID: <20150824134148.GA3394@afzalpc> (raw)
In-Reply-To: <F9B74F97-EF3F-4051-B54B-B6CDD2946374@gmail.com>
Hi,
On Mon, Aug 24, 2015 at 04:31:13PM +0800, yalin wang wrote:
>
> i only submit the bit reverse patch for arm / arm64 arch,
yes, saw later git blaming it on you :)
> > Not for this case, but once measured on ARM, iirc, a 32-bit asm bit
> > reversal as compared to doing it in C was taking 1 cycle as opposed to
> > ~225 cycles!, of course writing optimized C could have made it fare
> > better, but still would reach no-way near asm bit reversal.
The above measurement was done not in Linux, rather on a baremetal
code, but seeing the efficient Kernel C implementation, realized that
the gain would not be that much, it would be good to know if there are
measurements for Kernel bitreversal in C & asm (on supported arch)
Regards
afzal
WARNING: multiple messages have this Message-ID (diff)
From: Afzal Mohammed <afzal.mohd.ma@gmail.com>
To: yalin wang <yalin.wang2010@gmail.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>,
adaplas@gmail.com, plagnioj@jcrosoft.com,
linux-fbdev@vger.kernel.org,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [RFC] fbdev/riva:change to use generice function to implement reverse_order()
Date: Mon, 24 Aug 2015 19:11:48 +0530 [thread overview]
Message-ID: <20150824134148.GA3394@afzalpc> (raw)
In-Reply-To: <F9B74F97-EF3F-4051-B54B-B6CDD2946374@gmail.com>
Hi,
On Mon, Aug 24, 2015 at 04:31:13PM +0800, yalin wang wrote:
>
> i only submit the bit reverse patch for arm / arm64 arch,
yes, saw later git blaming it on you :)
> > Not for this case, but once measured on ARM, iirc, a 32-bit asm bit
> > reversal as compared to doing it in C was taking 1 cycle as opposed to
> > ~225 cycles!, of course writing optimized C could have made it fare
> > better, but still would reach no-way near asm bit reversal.
The above measurement was done not in Linux, rather on a baremetal
code, but seeing the efficient Kernel C implementation, realized that
the gain would not be that much, it would be good to know if there are
measurements for Kernel bitreversal in C & asm (on supported arch)
Regards
afzal
next prev parent reply other threads:[~2015-08-24 13:53 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-10 10:12 [RFC] fbdev/riva:change to use generice function to implement reverse_order() yalin wang
2015-08-10 10:12 ` yalin wang
2015-08-20 11:02 ` Tomi Valkeinen
2015-08-20 11:02 ` Tomi Valkeinen
2015-08-20 11:30 ` yalin wang
2015-08-20 11:30 ` yalin wang
2015-08-21 6:41 ` Tomi Valkeinen
2015-08-21 6:41 ` Tomi Valkeinen
2015-08-21 7:46 ` yalin wang
2015-08-21 7:46 ` yalin wang
2015-08-21 8:01 ` Tomi Valkeinen
2015-08-21 8:01 ` Tomi Valkeinen
2015-08-22 7:53 ` Afzal Mohammed
2015-08-22 7:53 ` Afzal Mohammed
2015-08-24 8:31 ` yalin wang
2015-08-24 8:31 ` yalin wang
2015-08-24 13:41 ` Afzal Mohammed [this message]
2015-08-24 13:53 ` Afzal Mohammed
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