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High single core CPU usage by MSDP media server NBU v7.5.0.4 on Windows Server 2008 R2 SP1...

Created: 16 Apr 2013 • Updated: 25 Apr 2013 | 3 comments
This issue has been solved. See solution.

I have an MSDP media server (Win Srvr 2008 R2 SP1) that has not had any tuning applied.

It is an HP DL180 G6 with 64 GB RAM and two Xeon E5620 CPUs, which yeilds 8 cores of 2.4 GHz.  Local disk is RAID-1 of 2 x 600 GB SAS-I (3.0 Gb/s) at 15k rpm, on HP P410 controller with 512 MB battery write cache, 25% read / 75% write.  C: for O/S and D: for programs on these two spindles.

E:\  2.0 TB  on SAN FC HP 3PAR                storage for MSDP database,

F:\ 60.0 TB on SAN FC NexSAN SATAbeast storage for MSDP data.

(FYI - NIC is 4 x 1 Gb/s of 802.3ad bonded - bond total is 25% to 30% busy - one NIC is >70% busy)

Under backup load I see one CPU core pretty much fixed at 80% to 90% load, and the other 7 cores all at never less than 15% each and never more than 20% each.

Q1) Does this seem normal - i.e. one very busy core, and seven not doing very much ?

Q2) spoold takes 4% to 5% of total CPU resource, and we know that each core is 12.5% of total - so spoold actually consumes about 1/3 to 1/2 of a core - so why is one core pretty much fixed at 80% usage?

FYI - This article touches on NUMA:

Q3) Has anyone actually applied the kernel thread tuning described in this article ?

Q4) Was there actually any measurable benefit from applying the kernel thread tuning ?


Operating Systems:

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Jaykullar's picture

Set your server to High performance in the O/S setting, then configure the Kernel Threads.

However it sounds more like a CPU problem, I would have a word with HP, I have seen this before where 1 CPU is running constantly high, can you change the affinity so the other CPU is used? There maybe notes flying about on the web about heat issues with these servers which cause CPU usage to be high.

jim dalton's picture

I read someplace on the forum that NB db isnt MT hence the platform preference is for high clock speed over core count. Which is why they now no longer are overly happy about running the master on say a Sun T series which has lots of cores (32) but theyre are all rather slow (1.2Ghz) relative to peak clock speeds available. This may not be entirely relevant but seems to tie in with one cpu taking a big hit.