From: Thomas Zimmermann <tzimmermann@suse.de>
To: Pekka Paalanen <ppaalanen@gmail.com>
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 19:48:19 +0100 [thread overview]
Message-ID: <44196aee-dedc-7019-2ca3-2801d8b5c2a8@suse.de> (raw)
In-Reply-To: <20220222150111.506d2cee@eldfell>
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Hi
Am 22.02.22 um 14:01 schrieb Pekka Paalanen:
> 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.
I copied some of the text from the other commit and I could have sworn I
updated it. But apparently not.
Best regards
Thomas
>
>
> Thanks,
> pq
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev
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next prev parent reply other threads:[~2022-02-22 18:48 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
2022-02-22 18:48 ` Thomas Zimmermann [this message]
2022-02-21 19:54 ` [PATCH v2 5/5] drm: Add TODO item for optimizing format helpers Thomas Zimmermann
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