From: Javier Martinez Canillas <javierm@redhat.com>
To: Thomas Zimmermann <tzimmermann@suse.de>,
daniel@ffwll.ch, deller@gmx.de, geert@linux-m68k.org
Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org
Subject: Re: [PATCH 2/2] fbdev: Improve performance of sys_imageblit()
Date: Fri, 18 Feb 2022 10:24:15 +0100 [thread overview]
Message-ID: <6c06a344-f998-1f15-0f94-c295d4831654@redhat.com> (raw)
In-Reply-To: <20220217103405.26492-3-tzimmermann@suse.de>
Hello Thomas,
On 2/17/22 11:34, Thomas Zimmermann wrote:
> Improve the performance of sys_imageblit() by manually unrolling
> the inner blitting loop and moving some invariants out. The compiler
> failed to do this automatically. The resulting binary code was even
> slower than the cfb_imageblit() helper, which uses the same algorithm,
> but operates on I/O memory.
>
> A microbenchmark measures the average number of CPU cycles
> for sys_imageblit() after a stabilizing period of a few minutes
> (i7-4790, FullHD, simpledrm, kernel with debugging). The value
> for CFB is given as a reference.
>
> sys_imageblit(), new: 25934 cycles
> sys_imageblit(), old: 35944 cycles
> cfb_imageblit(): 30566 cycles
>
> In the optimized case, sys_imageblit() is now ~30% faster than before
> and ~20% faster than cfb_imageblit().
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
This patch looks good to me as well.
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Best regards,
--
Javier Martinez Canillas
Linux Engineering
Red Hat
next prev parent reply other threads:[~2022-02-18 9:24 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-02-17 10:34 [PATCH 0/2] fbdev: Improve performance of fbdev console Thomas Zimmermann
2022-02-17 10:34 ` [PATCH 1/2] fbdev: Improve performance of sys_fillrect() Thomas Zimmermann
2022-02-18 9:09 ` Javier Martinez Canillas
2022-02-18 9:35 ` Sam Ravnborg
2022-02-17 10:34 ` [PATCH 2/2] fbdev: Improve performance of sys_imageblit() Thomas Zimmermann
2022-02-17 11:05 ` Gerd Hoffmann
2022-02-17 12:08 ` Thomas Zimmermann
2022-02-18 9:24 ` Javier Martinez Canillas [this message]
2022-02-18 10:14 ` Sam Ravnborg
2022-02-18 14:09 ` Thomas Zimmermann
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