Siddha, Suresh B wrote:
On Thu, May 24, 2007 at 12:43:58AM -0700, Peter Williams wrote:
Peter Williams wrote:
The relevant code, find_busiest_group() and find_busiest_queue(), has a
lot of code that is ifdefed by CONFIG_SCHED_MC and CONFIG_SCHED_SMT and,
as these macros were defined in the kernels I was testing with, I built
a kernel with these macros undefined and reran my tests. The
problems/anomalies were not present in 10 consecutive tests on this new
kernel. Even better on the few occasions that a 3/1 split did occur it
was quickly corrected to 2/2 and top was reporting approx 49% of CPU for
all spinners throughout each of the ten tests.
So all that is required now is an analysis of the code inside the ifdefs
to see why it is causing a problem.
Further testing indicates that CONFIG_SCHED_MC is not implicated and
it's CONFIG_SCHED_SMT that's causing the problem. This rules out the
code in find_busiest_group() as it is common to both macros.
I think this makes the scheduling domain parameter values the most
likely cause of the problem. I'm not very familiar with this code so
I've added those who've modified this code in the last year or
so to the
address of this e-mail.
What platform is this? I remember you mentioned its a 2 cpu box. Is it
dual core or dual package or one with HT?
It's a single CPU HT box i.e. 2 virtual CPUs. "cat /proc/cpuinfo" produces:
processor : 0
vendor_id : GenuineIntel
cpu family : 15
model : 3
model name : Intel(R) Pentium(R) 4 CPU 3.20GHz
stepping : 4
cpu MHz : 3201.145
cache size : 1024 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe
constant_tsc pni monitor ds_cpl cid xtpr
bogomips : 6403.97
clflush size : 64
processor : 1
vendor_id : GenuineIntel
cpu family : 15
model : 3
model name : Intel(R) Pentium(R) 4 CPU 3.20GHz
stepping : 4
cpu MHz : 3201.145
cache size : 1024 KB
physical id : 0
siblings : 2
core id : 0
cpu cores : 1
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 5
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe
constant_tsc pni monitor ds_cpl cid xtpr
bogomips : 6400.92
clflush size : 64
Peter
--
Peter Williams [EMAIL PROTECTED]
"Learning, n. The kind of ignorance distinguishing the studious."
-- Ambrose Bierce
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