Thread (2 messages) 2 messages, 2 authors, 2012-04-27

Kernelnewbies Digest, Vol 17, Issue 44

From: Jeshwanth Kumar N K Jeshu <hidden>
Date: 2012-04-26 17:40:14

Hello guys,
I am writing a user space code for pwm controller in beaglebone, but the
drivers are in the form of files, so when I am writing the code I got a
doubt that, if we keep access the files it may take more processor time so
any other way is there to access or this is the best way ?

On Thu, Apr 26, 2012 at 9:30 PM, [off-list ref]wrote:
Send Kernelnewbies mailing list submissions to
       kernelnewbies at kernelnewbies.org

To subscribe or unsubscribe via the World Wide Web, visit
       http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
or, via email, send a message with subject or body 'help' to
       kernelnewbies-request at kernelnewbies.org

You can reach the person managing the list at
       kernelnewbies-owner at kernelnewbies.org

When replying, please edit your Subject line so it is more specific
than "Re: Contents of Kernelnewbies digest..."


Today's Topics:

  1. Re: Profiling my Modules (Daniel Baluta)
  2. Re: Linux Driver Project (Bj?rn Mork)
  3. Re: Profiling my Modules (Rishi Agrawal)
  4. Re: Linux Driver Project (Bj?rn Mork)
  5. freelance kernel work (Christopher Harvey)


----------------------------------------------------------------------

Message: 1
Date: Thu, 26 Apr 2012 15:42:57 +0300
From: Daniel Baluta <redacted>
Subject: Re: Profiling my Modules
To: Rishi Agrawal <redacted>
Cc: kernelnewbies at kernelnewbies.org
Message-ID:
       <CAEnQRZCf1zjMAQSe8uuYTr7px6-K51fLpB+vwY3SMkDXimcpxw@mail.gmail.com
quoted
Content-Type: text/plain; charset=ISO-8859-1

On Thu, Apr 26, 2012 at 10:33 AM, Rishi Agrawal
[off-list ref] wrote:
quoted
Hi All,

I have a kernel module which has functions which take a lot of time in
execution. I am curious to know how can I profile it, and find out the
functions taking most of the time.

I saw Oprofile, but it seems that I will have to build the whole kernel,
and
quoted
also that it will be difficult to profile my module through it.

Any trick or tool will do.
Hello,

Have a look at perf [1].

thanks,
Daniel.

[1] https://perf.wiki.kernel.org/



------------------------------

Message: 2
Date: Thu, 26 Apr 2012 15:16:59 +0200
From: Bj?rn Mork <bjorn@mork.no>
Subject: Re: Linux Driver Project
To: Rabee Al-Maqabi <redacted>
Cc: Javier Martinez Canillas <redacted>,
       kernelnewbies at kernelnewbies.org
Message-ID: [ref]
Content-Type: text/plain; charset=utf-8

Rabee Al-Maqabi [off-list ref] writes:
quoted
Thank you for your reply. Linux Device Drivers is indeed a great book. I
have read it in addition to Understanding the Linux Kernel and I have
experimented with my Linux box. At this point, I would like to have a
real-world experience and write a driver for a piece of hardware not yet
supported.
How about a fingerprint scanner?  If you've got a modern laptop then
chances are good that you already own such a device.  And it's
most likely unsupported.  Some might say that's because it's useless :-)

Otherwise I'd recommend looking through your box of unused devices.  No
need to go out and buy anything if all you want is to write some
driver.

Or see
http://www.linuxdriverproject.org/foswiki/bin/view/Main/DriversNeeded
if you are open to buying some new device for this project.

You won't find any datasheets or any other documentation, though...
Manufacturers smart enough to provide documentation usually get drivers
written for their devices in no time.  But some still hold it to
themselves.  Go figure.


Bj?rn



------------------------------

Message: 3
Date: Thu, 26 Apr 2012 19:01:00 +0530
From: Rishi Agrawal <redacted>
Subject: Re: Profiling my Modules
To: Daniel Baluta <redacted>
Cc: kernelnewbies at kernelnewbies.org
Message-ID:
       <CADDndfPtRis6CuXJN7D0v=snCJ8b_hS0eW2cQoBekXE3UtyXSw@mail.gmail.com
quoted
Content-Type: text/plain; charset="iso-8859-1"

Thanks a lot, I will have a look at it and see if it helps.

On Thu, Apr 26, 2012 at 6:12 PM, Daniel Baluta <daniel.baluta@gmail.com
quoted
wrote:
quoted
On Thu, Apr 26, 2012 at 10:33 AM, Rishi Agrawal
[off-list ref] wrote:
quoted
Hi All,

I have a kernel module which has functions which take a lot of time in
execution. I am curious to know how can I profile it, and find out the
functions taking most of the time.

I saw Oprofile, but it seems that I will have to build the whole
kernel,
quoted
and
quoted
also that it will be difficult to profile my module through it.

Any trick or tool will do.
Hello,

Have a look at perf [1].

thanks,
Daniel.

[1] https://perf.wiki.kernel.org/


--
Regards,
Rishi Agrawal
-------------- next part --------------
An HTML attachment was scrubbed...
URL:
http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20120426/213b0716/attachment-0001.html

------------------------------

Message: 4
Date: Thu, 26 Apr 2012 15:51:10 +0200
From: Bj?rn Mork <bjorn@mork.no>
Subject: Re: Linux Driver Project
To: Rabee Al-Maqabi <redacted>
Cc: Javier Martinez Canillas <redacted>,
       kernelnewbies at kernelnewbies.org
Message-ID: [ref]
Content-Type: text/plain; charset=utf-8

Bj?rn Mork [off-list ref] writes:
quoted
How about a fingerprint scanner?  If you've got a modern laptop then
chances are good that you already own such a device.  And it's
most likely unsupported.  Some might say that's because it's useless :-)
Sorry, please ignore this.  I should have read
http://www.linuxdriverproject.org/foswiki/bin/view/Main/NoLinuxDriverNeeded
first.


Bj?rn



------------------------------

Message: 5
Date: Thu, 26 Apr 2012 10:39:41 -0500
From: Christopher Harvey <redacted>
Subject: freelance kernel work
To: <redacted>
Message-ID: [ref]
Content-Type: text/plain; charset=UTF-8; format=flowed

I'm not looking for work, nor do I have any work for others. I'm just
curious if there is a central location where freelance kernel
developers hang out. I've never seen any email on mailing lists like
"I have some hardware and want somebody to write a kernel module for
it". I thought that sort of request would have been common.



------------------------------

_______________________________________________
Kernelnewbies mailing list
Kernelnewbies at kernelnewbies.org
http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies


End of Kernelnewbies Digest, Vol 17, Issue 44
*********************************************


-- 
Regards
Jeshwanth Kumar N K
+91-7411483498
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.kernelnewbies.org/pipermail/kernelnewbies/attachments/20120426/71138959/attachment.html 
Keyboard shortcuts
hback out one level
jnext message in thread
kprevious message in thread
ldrill in
Escclose help / fold thread tree
?toggle this help