I have found out that /proc/meminfo doesn't have (at least that's my first
thought) info about shared memory (it shows 0, even in heavy duty servers).
ipcs also shows nothing, so how can I see the amount of shared memory being
used?
Th mounted /dev/shmem device also shows 0 kb used (just in case).
Saludos... :-)
--
Porqu? usar una base de datos relacional cualquiera,
si pod?s usar PostgreSQL?
-----------------------------------------------------------------
Mart?n Marqu?s | [email protected]
Programador, Administrador, DBA | Centro de Telematica
Universidad Nacional
del Litoral
-----------------------------------------------------------------
Hi,
>I have found out that /proc/meminfo doesn't have (at least that's my first
>thought) info about shared memory (it shows 0, even in heavy duty servers).
>ipcs also shows nothing, so how can I see the amount of shared memory being
>used?
>Th mounted /dev/shmem device also shows 0 kb used (just in case).
AFAIK you can't. Calculating how much shared mem is used in 2.4.x is just
too hard...
Greets,
Marc.
On Mi? 24 Oct 2001 20:17, Marc Brekoo wrote:
> Hi,
>
> >I have found out that /proc/meminfo doesn't have (at least that's my first
> >thought) info about shared memory (it shows 0, even in heavy duty
> > servers). ipcs also shows nothing, so how can I see the amount of shared
> > memory being used?
> >Th mounted /dev/shmem device also shows 0 kb used (just in case).
>
> AFAIK you can't. Calculating how much shared mem is used in 2.4.x is just
> too hard...
And this:
# ipcs
------ Shared Memory Segments --------
key shmid owner perms bytes nattch status
0x00000000 65536 nobody 600 46084 11 dest
------ Semaphore Arrays --------
key semid owner perms nsems status
0x00000000 393216 nobody 600 1
------ Message Queues --------
key msqid owner perms used-bytes messages
#
I can see 46084 bytes in shared memory used by the apache.
Am I wrong?
Saludos... :-)
--
Porqu? usar una base de datos relacional cualquiera,
si pod?s usar PostgreSQL?
-----------------------------------------------------------------
Mart?n Marqu?s | [email protected]
Programador, Administrador, DBA | Centro de Telematica
Universidad Nacional
del Litoral
-----------------------------------------------------------------
On Wed, 2001-10-24 at 19:27, Mart?n Marqu?s wrote:
> [...]
> ------ Shared Memory Segments --------
> key shmid owner perms bytes nattch status
> 0x00000000 65536 nobody 600 46084 11 dest
> [...]
> I can see 46084 bytes in shared memory used by the apache.
> Am I wrong?
Nope. Applications know how much the are sharing because they can
easily see what region of memory is shared/mapped into their's.
The reason the kernel can't figure out the net shared memory is because
there is no simple way -- it has to add up the shared regions of all
applications, counting each shared segment only once. Too much work.
Robert Love
On Mi? 24 Oct 2001 20:37, Robert Love wrote:
> On Wed, 2001-10-24 at 19:27, Mart?n Marqu?s wrote:
> > [...]
> > ------ Shared Memory Segments --------
> > key shmid owner perms bytes nattch status
> > 0x00000000 65536 nobody 600 46084 11 dest
> > [...]
> > I can see 46084 bytes in shared memory used by the apache.
> > Am I wrong?
>
> Nope. Applications know how much the are sharing because they can
> easily see what region of memory is shared/mapped into their's.
>
> The reason the kernel can't figure out the net shared memory is because
> there is no simple way -- it has to add up the shared regions of all
> applications, counting each shared segment only once. Too much work.
Yes, I guess you are right. I just checked on and old RH server with a 2.2.x
kernel, and the sum of the shared memory of each application doesn't give me
the amount of shared memory that free gives me.
Thanks to all!
--
Porqu? usar una base de datos relacional cualquiera,
si pod?s usar PostgreSQL?
-----------------------------------------------------------------
Mart?n Marqu?s | [email protected]
Programador, Administrador, DBA | Centro de Telematica
Universidad Nacional
del Litoral
-----------------------------------------------------------------
On Wed, Oct 24, 2001 at 07:37:26PM -0400, Robert Love wrote:
> On Wed, 2001-10-24 at 19:27, Mart?n Marqu?s wrote:
> > [...]
> > ------ Shared Memory Segments --------
> > key shmid owner perms bytes nattch status
> > 0x00000000 65536 nobody 600 46084 11 dest
> > [...]
> > I can see 46084 bytes in shared memory used by the apache.
> > Am I wrong?
>
> Nope. Applications know how much the are sharing because they can
> easily see what region of memory is shared/mapped into their's.
>
> The reason the kernel can't figure out the net shared memory is because
> there is no simple way -- it has to add up the shared regions of all
> applications, counting each shared segment only once. Too much work.
>
Actually, if it's done in the COW code, you could quite possibly get most of
it right there...
Does anyone know of something that can make use of the shmem accting?
Hi Mart?n,
On Wed, 24 Oct 2001, Mart?n Marqu?s wrote:
> I have found out that /proc/meminfo doesn't have (at least that's my
> first thought) info about shared memory (it shows 0, even in heavy
> duty servers).
/proc/meminfo did show the number of shared pages in the whole system
independent of SYSV shared mem.
In the -ac series it shows all shared anonymous pages
(i.e. tmpfs, shared mmap and SYSV shm pages)
> ipcs also shows nothing, so how can I see the amount
> of shared memory being used?
linux:~ # ipcs -mu
------ Shared Memory Status --------
segments allocated 3
pages allocated 256
pages resident 12
pages swapped 87
Swap performance: 0 attempts 0 successes
It shows it.
> Th mounted /dev/shmem device also shows 0 kb used (just in case).
That would only show the posix shared memory segments in this
instance.
Greetings
Christoph