Messages in this thread | | | From | "Oberman, Laurence (HAS GSE)" <> | Date | Fri, 14 Oct 2011 17:52:31 +0100 | Subject | RE: Regression in reading /proc/stat in the newer kernels with large SMP and NUMA configurations |
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Standard RHEL kernel build. What the customer would be using.
[root@linuxbeast boot]# cat config-2.6.32-131.6.1.el6.x86_64 | grep NR CONFIG_NR_CPUS=4096
-----Original Message----- From: Eric Dumazet [mailto:eric.dumazet@gmail.com] Sent: Friday, October 14, 2011 12:40 PM To: Oberman, Laurence (HAS GSE) Cc: Seger, Mark; linux-kernel@vger.kernel.org; Cabaniols, Sebastien Subject: RE: Regression in reading /proc/stat in the newer kernels with large SMP and NUMA configurations
Le vendredi 14 octobre 2011 à 17:27 +0100, Oberman, Laurence (HAS GSE) a écrit : > Eric, > > Got the system ready and ran the tests. > > This is a DL980 128 CPCUS, 256GB memory. > > [root@linuxbeast ~]# cat /proc/cpuinfo | grep processor | wc -l > 128 > > [root@linuxbeast ~]# uname -a > Linux linuxbeast.gse.mvlabs.corp.hp.com 2.6.32-131.6.1.el6.x86_64 #1 SMP Mon Jun 20 14:15:38 EDT 2011 x86_64 x86_64 x86_64 GNU/Linux > > In this example we take >4ms per read. We are spending most of the time in > > 35.09% t [kernel.kallsyms] [k] kstat_irqs_cpu > 32.13% t [kernel.kallsyms] [k] find_next_bit > 24.32% t [kernel.kallsyms] [k] show_stat > 1.98% t [kernel.kallsyms] [k] vsnprintf > 1.63% t [kernel.kallsyms] [k] format_decode > 1.23% t [kernel.kallsyms] [k] number
Hmm, have you compiled your kernel with NR_CPUS=4096 ???
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