High System CPU Usage Post: 302463090

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Operating Systems Linux Ubuntu High System CPU Usage Post 302463090 by mowmentous on Friday 15th of October 2010 04:32:24 PM

10-15-2010

Registered User

High System CPU Usage

I am running a Dell PE R815 with 4 x AMD 12 core CPUs with 128GB of RAM and a RAID 5 array of 6 SAS disks. This is an HPC application and is definitely CPU bound, however once I run 16 of these processes (thus pinning 16 cores) the work performed slows down dramatically, to maybe 5 or 10% of what it normally is capable of. Top shows that all HPC processes are using 100% CPU but they rather dramatically shift to system usage (rather than user). Here is a vmstat output:

Quote:

$ vmstat -S M 1 10
procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
r b swpd free buff cache si so bi bo in cs us sy id wa
46 0 0 64968 152 50747 0 0 3 41 0 0 11 32 57 0
46 0 0 64967 152 50747 0 0 0 15860 5255 127 6 89 4 0
46 0 0 64967 152 50747 0 0 0 0 5159 104 7 89 4 0
46 0 0 64968 152 50747 0 0 0 0 5153 106 7 89 4 0
46 0 0 64968 152 50747 0 0 0 40 5232 188 7 89 4 0
46 0 0 64968 152 50747 0 0 0 0 5014 102 7 90 3 0
46 0 0 64968 152 50747 0 0 0 4860 4896 107 7 88 5 0
46 0 0 64968 152 50747 0 0 0 0 5125 103 7 90 3 0
46 0 0 64968 152 50747 0 0 0 0 4987 104 7 89 4 0
46 0 0 64968 152 50747 0 0 0 2520 4805 184 7 89 4 0

To me it doesn't look like a RAM or Disk issue, but perhaps an IO or buffering issue. Please help!

-mowmentous

mowmentous

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LEARN ABOUT NETBSD

mfi

MFI(4)							   BSD Kernel Interfaces Manual 						    MFI(4)

NAME

     mfi -- LSI Logic & Dell MegaRAID SAS RAID controller

SYNOPSIS

     mfi* at pci? dev ? function ?

DESCRIPTION

     The mfi driver provides support for the MegaRAID SAS family of RAID controllers, including:

	   -   Dell PERC 5/e, PERC 5/i, PERC 6/e, PERC 6/i
	   -   Intel RAID Controller SRCSAS18E, SRCSAS144E
	   -   LSI Logic MegaRAID SAS 8208ELP, MegaRAID SAS 8208XLP, MegaRAID SAS 8300XLP, MegaRAID SAS 8308ELP, MegaRAID SAS 8344ELP, MegaRAID
	       SAS 8408E, MegaRAID SAS 8480E, MegaRAID SAS 8708ELP, MegaRAID SAS 8888ELP, MegaRAID SAS 8880EM2, MegaRAID SAS 9260-8i
	   -   IBM ServeRAID M1015, ServeRAID M5014

     These controllers support RAID 0, RAID 1, RAID 5, RAID 6, RAID 10, RAID 50 and RAID 60 using either SAS or SATA II drives.

     Although the controllers are actual RAID controllers, the driver makes them look just like SCSI controllers.  All RAID configuration is done
     through the controllers' BIOSes.

     mfi supports monitoring of the logical disks in the controller through the bioctl(8) and envstat(8) commands.

EVENTS

     The mfi driver is able to send events to powerd(8) if a logical drive in the controller is not online.  The state-changed event will be sent
     to the /etc/powerd/scripts/sensor_drive script when such condition happens.

SEE ALSO

     intro(4), pci(4), scsi(4), sd(4), bioctl(8), envstat(8), powerd(8)

HISTORY

     The mfi driver first appeared in NetBSD 4.0.

BSD
								  March 22, 2012							       BSD