From: Misbah khan <misbah_khan@engineer.com>
To: linuxppc-embedded@ozlabs.org
Subject: Re: floating point support in the driver.
Date: Fri, 1 Aug 2008 05:00:09 -0700 (PDT) [thread overview]
Message-ID: <18772952.post@talk.nabble.com> (raw)
In-Reply-To: <200808011332.25368.laurentp@cse-semaphore.com>
I am not very clear Why floating point support in the Kernel should be
avoided ?
We want our DSP algorithm to run at the boot time and since kernel thread
having higher priority , i assume that it would be faster than user
application.
If i really have to speed up my application execution what mechanism will
you suggest me to try ?
After using Hardware VFP support also i am still laging the timing
requirement by 800 ms in my case
---- Misbah <><
Laurent Pinchart-4 wrote:
>
> On Friday 01 August 2008, Misbah khan wrote:
>>
>> Hi all,
>>
>> I have a DSP algorithm which i am running in the application even after
>> enabling the VFP support it is taking a lot of time to get executed hence
>>
>> I want to transform the same into the driver insted of an user
>> application.
>> Can anybody suggest whether doing the same could be a better solution and
>> what could be the chalenges that i have to face by implimenting such
>> floating point support in the driver.
>>
>> Is there a way in the application itself to make it execute faster.
>
> Floating-point in the kernel should be avoided. FPU state save/restore
> operations are costly and are not performed by the kernel when switching
> from userspace to kernelspace context. You will have to protect
> floating-point sections with kernel_fpu_begin/kernel_fpu_end which, if I'm
> not mistaken, disables preemption. That's probably not something you want
> to do. Why would the same code run faster in kernelspace then userspace ?
>
> --
> Laurent Pinchart
> CSE Semaphore Belgium
>
> Chaussee de Bruxelles, 732A
> B-1410 Waterloo
> Belgium
>
> T +32 (2) 387 42 59
> F +32 (2) 387 42 75
>
>
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-embedded
>
--
View this message in context: http://www.nabble.com/floating-point-support-in-the-driver.-tp18772109p18772952.html
Sent from the linuxppc-embedded mailing list archive at Nabble.com.
next prev parent reply other threads:[~2008-08-01 12:00 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-08-01 10:57 floating point support in the driver Misbah khan
2008-08-01 11:32 ` Laurent Pinchart
2008-08-01 12:00 ` Misbah khan [this message]
2008-08-01 15:54 ` M. Warner Losh
2008-08-04 5:23 ` Misbah khan
2008-08-04 5:33 ` M. Warner Losh
2008-08-04 5:47 ` David Hawkins
2008-08-05 9:49 ` Misbah khan
2008-08-05 16:53 ` David Hawkins
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=18772952.post@talk.nabble.com \
--to=misbah_khan@engineer.com \
--cc=linuxppc-embedded@ozlabs.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).