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From: Pekka Paalanen <ppaalanen@gmail.com>
To: Thomas Zimmermann <tzimmermann@suse.de>
Cc: linux-fbdev@vger.kernel.org, deller@gmx.de, javierm@redhat.com,
	dri-devel@lists.freedesktop.org, geert@linux-m68k.org,
	kraxel@redhat.com, sam@ravnborg.org
Subject: Re: [PATCH v2 4/5] fbdev: Improve performance of cfb_imageblit()
Date: Tue, 22 Feb 2022 15:01:11 +0200	[thread overview]
Message-ID: <20220222150111.506d2cee@eldfell> (raw)
In-Reply-To: <20220221195410.9172-5-tzimmermann@suse.de>

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On Mon, 21 Feb 2022 20:54:09 +0100
Thomas Zimmermann <tzimmermann@suse.de> wrote:

> Improve the performance of sys_imageblit() by manually unrolling

sys?

> the inner blitting loop and moving some invariants out. The compiler
> failed to do this automatically. This change keeps cfb_imageblit()
> in sync with sys_imagebit().

This is correct here.

> 
> A microbenchmark measures the average number of CPU cycles
> for sys_imageblit() after a stabilizing period of a few minutes

sys?

> (i7-4790, FullHD, simpledrm, kernel with debugging).
> 
> sys_imageblit(), new: 15724 cycles

sys?

> cfb_imageblit(): old: 30566 cycles
> 
> In the optimized case, cfb_imageblit() is now ~2x faster than before.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>  drivers/video/fbdev/core/cfbimgblt.c | 51 +++++++++++++++++++++++-----
>  1 file changed, 42 insertions(+), 9 deletions(-)

Just noticed some confusion in the commit message.


Thanks,
pq

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  reply	other threads:[~2022-02-22 13:01 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-02-21 19:54 [PATCH v2 0/5] fbdev: Improve performance of fbdev console Thomas Zimmermann
2022-02-21 19:54 ` [PATCH v2 1/5] fbdev: Improve performance of sys_fillrect() Thomas Zimmermann
2022-02-21 19:54 ` [PATCH v2 2/5] fbdev: Improve performance of sys_imageblit() Thomas Zimmermann
2022-02-21 19:54 ` [PATCH v2 3/5] fbdev: Remove trailing whitespaces from cfbimgblt.c Thomas Zimmermann
2022-02-21 19:54 ` [PATCH v2 4/5] fbdev: Improve performance of cfb_imageblit() Thomas Zimmermann
2022-02-22 13:01   ` Pekka Paalanen [this message]
2022-02-22 18:48     ` Thomas Zimmermann
2022-02-21 19:54 ` [PATCH v2 5/5] drm: Add TODO item for optimizing format helpers Thomas Zimmermann

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