Hey,
I''m currently trying to measure the CPU Usage of a process
that''s
running on a Linode VM, which is virtualised using Xen. It appears to
exhibit very weird CPU Usage statistics and I was wondering if anyone
could explain how/why this is happening. I am running a series of
processes, each of which entirely pegs a core.
Pegging 1 Core = 14% of CPU
Pegging 2 Cores = 28% of CPU
Pegging 3 Cores = 60% of CPU
Pegging 4 Cores = 100% of CPU
Those are the CPU stats as listed in both vmstat and top - so I''m
presuming that they''re coming from /proc/stat. I''m not seeing
any
''steal'' time at all, so I presume that I have access to all
the CPU
cores nominally available, I have appended the contents of
/proc/cpuinfo to the bottom of the page. The weird thing is that if
you look at the processes'' individual CPU Usage measurement then it is
listed as 100% (ie a whole core). I would consequently expected
vmstat to be listing 25%, 50%, 75%, 100% on a 4 core box. Thanks for
any help explaining what is going on here.
regards,
Richard
processor : 0
vendor_id : GenuineIntel
cpu family : 6
model : 26
model name : Intel(R) Xeon(R) CPU L5520 @ 2.27GHz
stepping : 5
cpu MHz : 2266.746
cache size : 8192 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu de tsc msr pae cx8 cmov pat clflush mmx fxsr sse
sse2 ss ht nx constant_tsc nonstop_tsc pni ssse3 sse4_1 sse4_2 popcnt
hypervisor
bogomips : 4533.49
clflush size : 64
cache_alignment : 64
address sizes : 40 bits physical, 48 bits virtual
power management:
processor : 1
vendor_id : GenuineIntel
cpu family : 6
model : 26
model name : Intel(R) Xeon(R) CPU L5520 @ 2.27GHz
stepping : 5
cpu MHz : 2266.746
cache size : 8192 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu de tsc msr pae cx8 cmov pat clflush mmx fxsr sse
sse2 ss ht nx constant_tsc nonstop_tsc pni ssse3 sse4_1 sse4_2 popcnt
hypervisor
bogomips : 4533.49
clflush size : 64
cache_alignment : 64
address sizes : 40 bits physical, 48 bits virtual
power management:
processor : 2
vendor_id : GenuineIntel
cpu family : 6
model : 26
model name : Intel(R) Xeon(R) CPU L5520 @ 2.27GHz
stepping : 5
cpu MHz : 2266.746
cache size : 8192 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu de tsc msr pae cx8 cmov pat clflush mmx fxsr sse
sse2 ss ht nx constant_tsc nonstop_tsc pni ssse3 sse4_1 sse4_2 popcnt
hypervisor
bogomips : 4533.49
clflush size : 64
cache_alignment : 64
address sizes : 40 bits physical, 48 bits virtual
power management:
processor : 3
vendor_id : GenuineIntel
cpu family : 6
model : 26
model name : Intel(R) Xeon(R) CPU L5520 @ 2.27GHz
stepping : 5
cpu MHz : 2266.746
cache size : 8192 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 11
wp : yes
flags : fpu de tsc msr pae cx8 cmov pat clflush mmx fxsr sse
sse2 ss ht nx constant_tsc nonstop_tsc pni ssse3 sse4_1 sse4_2 popcnt
hypervisor
bogomips : 4533.49
clflush size : 64
cache_alignment : 64
address sizes : 40 bits physical, 48 bits virtual
power management:
