(unknown)

Hi all,
How I can disable printk() output bufferization ? I need that printk() prints symbol-by-symbol or line-by-line.

Thank you.
--
Regards,
Alexei Babich, chematic engineer, OOO NPP "Rezonans", Chelyabinsk, Russia
http://www.rez.ru
Jabber ID: impatt@jabber.ru
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Re:

On Mon, May 19, 2008 at 6:57 PM, Alexei Babich wrote:
> Hi all,
> How I can disable printk() output bufferization ? I need that printk() prints symbol-by-symbol or line-by-line.
>

Check this out - since it has similar embedded requirements like yours
(what is a chematic engineer?):

http://tree.celinuxforum.org/pipermail/celinux-dev/2006-July /001261.html

Read the comments part of kernel/printk.c - printk() is an amazing
function, because it can be called in ANY CONTEXT.....which also means
that it cannot sleep. But since u know many I/O function involved
some form of waiting, therefore printk() necessarily HAVE TO WRITE TO
A BUFFER, and it only write to the screen/console whenever it is
allowed to sleep (which involved holding a console semaphore).

In short, printk() sometimes will output to screen directly, esp when
u are not in the interrupt context. Otherwise it may just buffer for
later delivery.

> Thank you.
> --
> Regards,
> Alexei Babich, chematic engineer, OOO NPP "Rezonans", Chelyabinsk, Russia
> http://www.rez.ru
> Jabber ID: impatt@jabber.ru
> --


--
Regards,
Peter Teoh
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Re:

> Check this out - since it has similar embedded requirements like yours
> (what is a chematic engineer?):
I ment circuit, not schematic, and that's a misprint in addition :)

> http://tree.celinuxforum.org/pipermail/celinux-dev/2006-July /001261.html
Thank you for link.

>
> Read the comments part of kernel/printk.c - printk() is an amazing
> function, because it can be called in ANY CONTEXT.....which also means
> that it cannot sleep. But since u know many I/O function involved
> some form of waiting, therefore printk() necessarily HAVE TO WRITE TO
> A BUFFER,
OK, I need decrease buffer depth.
Thank you.

--
Regards,
Alexei Babich, circuit engineer, OOO NPP "Rezonans", Chelyabinsk, Russia
http://www.rez.ru
Jabber ID: impatt@jabber.ru
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how to find when a symbol introduced into the kernel

Hi all

To write multiple kernel version compatible programs, I need to know when a specific symbol (a struct or a function)were introduced in to the kernel tree

Binary search against multiple kernel sources is a way,but is still slow.Is there any fast way to use modern git technology to make my life easier?

Many thanks.

Best Regards
Zhaohui Wang


> -----Original Message-----
> From: linux-newbie-owner@vger.kernel.org [mailto:linux-newbie-
> owner@vger.kernel.org] On Behalf Of Alexei Babich
> Sent: Friday, May 30, 2008 7:06 AM
> To: linux-newbie@vger.kernel.org
> Subject: Re:
>
> > Check this out - since it has similar embedded requirements like
> yours
> > (what is a chematic engineer?):
> I ment circuit, not schematic, and that's a misprint in addition :)
>
> > http://tree.celinuxforum.org/pipermail/celinux-dev/2006-
> July/001261.html
> Thank you for link.
>
> >
> > Read the comments part of kernel/printk.c - printk() is an amazing
> > function, because it can be called in ANY CONTEXT.....which also
> means
> > that it cannot sleep. But since u know many I/O function involved
> > some form of waiting, therefore printk() necessarily HAVE TO WRITE TO
> > A BUFFER,
> OK, I need decrease buffer depth.
> Thank you.
>
> --
> Regards,
> Alexei Babich, circuit engineer, OOO NPP "Rezonans", Chelyabinsk,
> Russia
> http://www.rez.ru
> Jabber ID: impatt@jabber.ru
> --
> To unsubscribe from this list: send the line "unsubscribe linux-newbie"
> in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.linux-learn.org/faqs

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