Number of CPUs detected by Bind 9.4.2 on 4 CPU system running RedHat es 4.

[Jeff Lightner]

Did you reboot the box at some point?  

Typically on the older boxes during install it would build both an SMP
kernel and a non-SMP kernel.   During boot grub would default to one
kernel or another but give you the opportunity to interrupt the boot and
pick the kernel.  If you interrupted boot then told it to boot from the
kernel that doesn't have smp at the end of its name you're not doing
multi-processor.  The fix for this is simply to reboot and be sure you
are booting from the smp kernel.

-----Original Message-----
From: bind-users-bounce at isc.org [mailto:bind-users-bounce at isc.org] On
Behalf Of greg kuechle
Sent: Monday, March 31, 2008 3:46 PM
To: bind-users at isc.org
Subject: Re: Number of CPUs detected by Bind 9.4.2 on 4 CPU system
running RedHat es 4.

Hello Matus,
I didn't upgrade the kernel. The kernel supports multiple CPUs. The only
thing that I upgraded was named. I built it from the souce code.The
older
version that came with the RedHat OS as a package uses all of the CPUs,
yet
when I compile named on the system it will only see 1 CPU.

When I compile and run the following code:

#include <stdio.h>
#include <usistd.h>

int main()
{
       printf("ncpus: %d\n" , sysconf((_SC_NPROCESSORS_ONLN))):
       return(0);
}

The result is:
ncpus: 4

There seems to be a problem with the way the 9.4.2 code is getting built
on
my RedHat systems.

I compiled using the following:
$INSTALL_DIR/configure --prefix=/opt/named --with-openssl
--enable-threads
make
make install

I have three other servers that have the same problem. They are all
running
RedHat es4.
These are production servers, so I require the use of all of the CPUs.

I also tryed starting named without the -n switch and only one CPU is
detected and one worker thread is started.

Thanks for any Help.
Greg.


On Mon, Mar 31, 2008 at 1:19 PM, Matus UHLAR - fantomas
<uhlar at fantomas.sk>
wrote:

> On 31.03.08 11:59, greg kuechle wrote:
> > I have install bind 9.4.2 on a system with 4 CPUs running RedHat
es4. I
> > compiled named with the --enable-threads  and used the -n 4 flag
when I
> > start named.
> >
> > Mar 31 10:12:24 ******** named[4897]: starting BIND 9.4.2  -t
/opt/named
> > -u named -n 4 -c /etc/named.conf
> > Mar 31 16:12:24 ******** named[4897]: found 1 CPU, using 4 worker
> threads
>
> does your kernel support more CPUs? Seems it does not. Maybe you
should
> re-compile or use another (SMP) kernel.
>
> > Before I upgraded the system it was running an older version of
named
> that
> > comes packaged with the OS.
> > Here is the output from the logfile.
>
> > Mar 24 11:34:13 ******** named[5877]: starting BIND 9.2.4
> > Mar 24 11:34:13 ******** named[5877]: using 4 CPUs
>
> seems named found 4 CPUs here... you had SMP kernel before the
upgrade.
>
> > Did I compile named wrong?
>
> the kernel, not the named, imho.
>
> > Will BIND 9.4.2 use all of the CPUs if I use the -n 4 option at
startup?
>
> No, named will create 4 threads if you use "-n 4", independently on
number
> of CPUs in the system. Whether threads will be run on more CPU's,
depends
> completely on the kernel. On single-processor kernel everything will
use
> just one CPU.
>
> If you don't use the "-n" switch, named will detect the number of
> processors
> and decide itself, how much threads to start. That's recommended and
> default.
>
> > It looks like named is only running on one CPU. Will named start
using
> the
> > other CPUs once one CPU is up to 100% ?
>
> I doubt, see above.
> --
> Matus UHLAR - fantomas, uhlar at fantomas.sk ; http://www.fantomas.sk/
> Warning: I wish NOT to receive e-mail advertising to this address.
> Varovanie: na tuto adresu chcem NEDOSTAVAT akukolvek reklamnu postu.
> The early bird may get the worm, but the second mouse gets the cheese.
>
>
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