on 10-18-2008 9:47 PM
Hi,
we just started with using Linux as platform for SAP ... so we have e.g. one system (ECC 6.00) running on a server with SUSE Linux Enterprise Server 10 (x86_64), version 2.6.16.46-0.12-smp ...
On this server we have really performance problems due to a CPU utilization of nearly 100% ... now it is so that hardware is 4 quad core CPUs ... 16 cores in total ... should be miore then enough for this server ...
When checking CPU in transaction ST06, only 4 CPUs are shown ... according to my understanding (what might be wrong), there should be 16 CPUs visible (as there are 16 cores available) ...
When executing grep -i core /proc/cpuinfo on the server, 4 CPUs with 4 cores each are shown ... so everything seems to be ok ... but also when using "top" command (and pressing "1" to get a overview for the different CPUs) only 4 CPUs are shown (and not 16 ... what I would expect) ...
So my feeling is that we use only 25 % of the available capacity here ...
Thanks for any hints here ... most important would be to know if this "behaviour" (show only 4 CPUs) is correct ...
cheers
Thomas
PS: we have not installed Linux on our own ... we are using an outsourcer for hardware and OS ...
Hi Thomas,
i have a dual socket quad core machine here and checked st06 and there i see:
CPU: Count: 8
which is correct. I'm currently using "SAPOSCOL version COLL 20.95 710", maybe you can give it a try to download new version.
Another strange thing is, that you only see 4 CPU's in top, whereas I see 8 CPUs (cores, respectively) in my environment.
To answer your last question, showing only 4 CPUs is wrong, both saposcol and top are aware of CPU cores.
Thanks,
Hannes
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Hello Hannes,
thanks for your quick reply ... ok, we are using saposcol with following version ... "COLL 20.95 700 - v2.16, AMD/Intel x86_64 with Linux" ... this is the latest available version for kernel 7.00 ... but the different cores are not shown ...
My feeling is that there is something wrong with Linux setup ... it seems that server is using just one core of each physical CPU ...
Maybe you have an idea if usage of CPU cores can be restricted somehow with Linux setup ? Or might be that cores have to be assigned somehow for usage ?
best regards
Thomas
Hi Thomas,
I'm not sure or aware how one coult do this, as you have all cores available via /proc/cpuinfo. Using 'taskset' you could limit the number of CPUs the scheduler would be able to use for a certain application binary, but in general you are still able to see all CPU's installed.
I'd suggest that you contact your outsourcing partner and face him with your findings. Maybe there is something wrong with the configuration ...
Thanks,
Hannes
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