2.4.7: wtf is "ksoftirqd_CPU0"

2.4.7: wtf is "ksoftirqd_CPU0"

[peter k.]

i just installed 2.4.7, now a new process called "ksoftirqd_CPU0" is started
automatically when booting (by the kernel obviously)? why? what does it do?
i didnt find any useful information on it in linuxdoc / linux-kernel
archives

Re: 2.4.7: wtf is "ksoftirqd_CPU0"

[peter k.]

i knew that i forgot to say something: i was using 2.4.6 before and i never
saw that process with 2.4.6 or any other 2.4.x version


> i just installed 2.4.7, now a new process called "ksoftirqd_CPU0" is
started
> automatically when booting (by the kernel obviously)? why? what does it
do?
> i didnt find any useful information on it in linuxdoc / linux-kernel
> archives

Re: 2.4.7: wtf is "ksoftirqd_CPU0"

[peter k.]

> > i just installed 2.4.7, now a new process called "ksoftirqd_CPU0"
> > is started
> > automatically when booting (by the kernel obviously)? why? what
> > does it do?
> > i didnt find any useful information on it in linuxdoc / linux-kernel
> > archives
>
> It's the kernel soft IRQ daemon. It provides a context from which to
> execute 'slow' code that was triggered by an interrupt. There will be one
> per CPU.
>
> DS

why wasnt it run in previous kernels? im just wondering why it suddenly
appeared without anyone saying a word about it ;)

Re: 2.4.7: wtf is "ksoftirqd_CPU0"

[Arnaldo Carvalho de Melo]

Em Sat, Jul 21, 2001 at 06:29:37PM +0200, peter k. escreveu:
> 
> > > i just installed 2.4.7, now a new process called "ksoftirqd_CPU0"
> > > is started
> > > automatically when booting (by the kernel obviously)? why? what
> > > does it do?
> > > i didnt find any useful information on it in linuxdoc / linux-kernel
> > > archives
> > It's the kernel soft IRQ daemon. It provides a context from which to
> > execute 'slow' code that was triggered by an interrupt. There will be one
> > per CPU.
> 
> why wasnt it run in previous kernels? im just wondering why it suddenly

because previous kernels had problems that Andrea's approach fixes? Read
the archives for the thread about it.

- Arnaldo

Re: 2.4.7: wtf is "ksoftirqd_CPU0"

[Jeff Garzik]

"peter k." wrote:
> 
> i just installed 2.4.7, now a new process called "ksoftirqd_CPU0" is started
> automatically when booting (by the kernel obviously)? why? what does it do?
> i didnt find any useful information on it in linuxdoc / linux-kernel
> archives

it is used internally, ignore it.

-- 
Jeff Garzik      | "I wouldn't be so judgemental
Building 1024    |  if you weren't such a sick freak."
MandrakeSoft     |             -- goats.com

Re: 2.4.7: wtf is "ksoftirqd_CPU0"

[Dave Jones]

On Sat, 21 Jul 2001, peter k. wrote:

> why wasnt it run in previous kernels?

Because it was only added to mainline in 2.4.7

> im just wondering why it suddenly
> appeared without anyone saying a word about it ;)

>From the changelog...

-pre8:
- Paul Mackerras: PPC updates (softirq)

-pre5:
- Andrea Arkangeli: softirq cleanups and fixes, and everybody is happy
  again (ie I changed some details to make me happy ;)

There were also several discussions about Andreas ksoftirq patches
a few weeks back.

regards,

Dave.

-- 
| Dave Jones.        http://www.suse.de/~davej
| SuSE Labs

Re: 2.4.7: wtf is "ksoftirqd_CPU0"

[Daniel Phillips]

On Saturday 21 July 2001 18:38, Jeff Garzik wrote:
> "peter k." wrote:
> > i just installed 2.4.7, now a new process called "ksoftirqd_CPU0"
> > is started automatically when booting (by the kernel obviously)?
> > why? what does it do? i didnt find any useful information on it in
> > linuxdoc / linux-kernel archives
>
> it is used internally, ignore it.

It's pretty hard to ignore a process with a name that ugly ;-)

How about just ksoft0 ?  Or kirq0?

I don't see the sense of trying to encode a whole sentence into the 
process name.

(Peter, this handles softirqs in a more predictable way by allowing the 
scheduler to take care of any softirq that can't conveniently be 
executed immediately.  Among other benefits, this approach eliminated 
the need to check for and execute pending softirqs on exit from system 
calls.)

--
Daniel

Re: 2.4.7: wtf is "ksoftirqd_CPU0"

[Horst von Brand]

Jeff Garzik <jgarzik@mandrakesoft.com> said:
> "peter k." wrote:

> > i just installed 2.4.7, now a new process called "ksoftirqd_CPU0" is
> > started automatically when booting (by the kernel obviously)? why? what
> > does it do?  i didnt find any useful information on it in linuxdoc /
> > linux-kernel archives

> it is used internally, ignore it.

I'd advise not to do so in general: It is a rather tempting name for
crackers to hide illegal activities.
-- 
Horst von Brand                             vonbrand@sleipnir.valparaiso.cl
Casilla 9G, Vin~a del Mar, Chile                               +56 32 672616

Re: 2.4.7: wtf is "ksoftirqd_CPU0"

[P.A.M. van Dam]

On Sat, Jul 21, 2001 at 08:23:36PM -0400, Horst von Brand wrote:
> Jeff Garzik <jgarzik@mandrakesoft.com> said:
> > "peter k." wrote:
> 
> > > i just installed 2.4.7, now a new process called "ksoftirqd_CPU0" is
> > > started automatically when booting (by the kernel obviously)? why? what
> > > does it do?  i didnt find any useful information on it in linuxdoc /
> > > linux-kernel archives
> 
> > it is used internally, ignore it.
> 
> I'd advise not to do so in general: It is a rather tempting name for
> crackers to hide illegal activities.

Kernel daemons/threads still use "reserved pids" (< 100 I believe) so it's
pretty to distinguish them. Ofcourse on 128-way SMP machine, things would
be rather difficult. 

Best regards,

	Pascal


> -- 
> Horst von Brand                             vonbrand@sleipnir.valparaiso.cl
> Casilla 9G, Vin~a del Mar, Chile                               +56 32 672616
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" 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.tux.org/lkml/