How-to determine the number of physical CPUs

lusine · 06-08-2012, 08:28 AM

Hi

Few days ago i had problems with one of my sites, which use too much CPU.
Typing "TOP" i got that mysqld use 200-400 %CPU.

As i cann't find the real reason, i move it to another host - where it work well without any problem.

Now, when on previous host everying is well i check that mysql %CPU is fine, but TIME+ digits usually are very high - like in this example.

Can anybody explain what this mean "137:31.72"

PHP Code:


			
 PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND

 8927 apache    20   0 36228  14m 5016 S  4.7  0.7   0:11.32 httpd

 1771 mysql     20   0 53172  31m 4340 S  0.7  1.5 137:31.72 mysqld

Also, as i understand on previous host there are 4 processores, and 2 cores

grep "core id" /proc/cpuinfo

PHP Code:


			
[root@www ~]# grep "core id" /proc/cpuinfo

core id         : 0

core id         : 0

core id         : 1

core id         : 1

but cann't understand how many cores are on new host (with 8 processors)

PHP Code:


			
[root@host ~]# cat /proc/cpuinfo

processor       : 0

vendor_id       : GenuineIntel

cpu family      : 6

model           : 23

model name      : Intel(R) Xeon(R) CPU           L5420  @ 2.50GHz

stepping        : 10

cpu MHz         : 2499.994

cache size      : 6144 KB

fdiv_bug        : no

hlt_bug         : no

f00f_bug        : no

coma_bug        : no

fpu             : yes

fpu_exception   : yes

cpuid level     : 13

wp              : yes

flags           : fpu tsc msr pae cx8 apic cmov pat clflush acpi mmx fxsr sse sse2 ss ht nx constant_tsc pni vmx est ssse3 sse4_1

bogomips        : 6258.29



processor       : 1

vendor_id       : GenuineIntel

cpu family      : 6

model           : 23

model name      : Intel(R) Xeon(R) CPU           L5420  @ 2.50GHz

stepping        : 10

cpu MHz         : 2499.994

cache size      : 6144 KB

fdiv_bug        : no

hlt_bug         : no

f00f_bug        : no

coma_bug        : no

fpu             : yes

fpu_exception   : yes

cpuid level     : 13

wp              : yes

flags           : fpu tsc msr pae cx8 apic cmov pat clflush acpi mmx fxsr sse sse2 ss ht nx constant_tsc up pni vmx est ssse3 sse4_1

bogomips        : 6258.29



processor       : 2

vendor_id       : GenuineIntel

cpu family      : 6

model           : 23

model name      : Intel(R) Xeon(R) CPU           L5420  @ 2.50GHz

stepping        : 10

cpu MHz         : 2499.994

cache size      : 6144 KB

fdiv_bug        : no

hlt_bug         : no

f00f_bug        : no

coma_bug        : no

fpu             : yes

fpu_exception   : yes

cpuid level     : 13

wp              : yes

flags           : fpu tsc msr pae cx8 apic cmov pat clflush acpi mmx fxsr sse sse2 ss ht nx constant_tsc up pni vmx est ssse3 sse4_1

bogomips        : 6258.29



processor       : 3

vendor_id       : GenuineIntel

cpu family      : 6

model           : 23

model name      : Intel(R) Xeon(R) CPU           L5420  @ 2.50GHz

stepping        : 10

cpu MHz         : 2499.994

cache size      : 6144 KB

fdiv_bug        : no

hlt_bug         : no

f00f_bug        : no

coma_bug        : no

fpu             : yes

fpu_exception   : yes

cpuid level     : 13

wp              : yes

flags           : fpu tsc msr pae cx8 apic cmov pat clflush acpi mmx fxsr sse sse2 ss ht nx constant_tsc up pni vmx est ssse3 sse4_1

bogomips        : 6258.29



processor       : 4

vendor_id       : GenuineIntel

cpu family      : 6

model           : 23

model name      : Intel(R) Xeon(R) CPU           L5420  @ 2.50GHz

stepping        : 10

cpu MHz         : 2499.994

cache size      : 6144 KB

fdiv_bug        : no

hlt_bug         : no

f00f_bug        : no

coma_bug        : no

fpu             : yes

fpu_exception   : yes

cpuid level     : 13

wp              : yes

flags           : fpu tsc msr pae cx8 apic cmov pat clflush acpi mmx fxsr sse sse2 ss ht nx constant_tsc up pni vmx est ssse3 sse4_1

bogomips        : 6258.29



processor       : 5

vendor_id       : GenuineIntel

cpu family      : 6

model           : 23

model name      : Intel(R) Xeon(R) CPU           L5420  @ 2.50GHz

stepping        : 10

cpu MHz         : 2499.994

cache size      : 6144 KB

fdiv_bug        : no

hlt_bug         : no

f00f_bug        : no

coma_bug        : no

fpu             : yes

fpu_exception   : yes

cpuid level     : 13

wp              : yes

flags           : fpu tsc msr pae cx8 apic cmov pat clflush acpi mmx fxsr sse sse2 ss ht nx constant_tsc up pni vmx est ssse3 sse4_1

bogomips        : 6258.29



processor       : 6

vendor_id       : GenuineIntel

cpu family      : 6

model           : 23

model name      : Intel(R) Xeon(R) CPU           L5420  @ 2.50GHz

stepping        : 10

cpu MHz         : 2499.994

cache size      : 6144 KB

fdiv_bug        : no

hlt_bug         : no

f00f_bug        : no

coma_bug        : no

fpu             : yes

fpu_exception   : yes

cpuid level     : 13

wp              : yes

flags           : fpu tsc msr pae cx8 apic cmov pat clflush acpi mmx fxsr sse sse2 ss ht nx constant_tsc up pni vmx est ssse3 sse4_1

bogomips        : 6258.29



processor       : 7

vendor_id       : GenuineIntel

cpu family      : 6

model           : 23

model name      : Intel(R) Xeon(R) CPU           L5420  @ 2.50GHz

stepping        : 10

cpu MHz         : 2499.994

cache size      : 6144 KB

fdiv_bug        : no

hlt_bug         : no

f00f_bug        : no

coma_bug        : no

fpu             : yes

fpu_exception   : yes

cpuid level     : 13

wp              : yes

flags           : fpu tsc msr pae cx8 apic cmov pat clflush acpi mmx fxsr sse sse2 ss ht nx constant_tsc up pni vmx est ssse3 sse4_1

bogomips        : 6258.29

As this command don't work on that host

PHP Code:


			
[root@host ~]# grep "core id" /proc/cpuinfo

[root@host ~]#

thank you

neonsignal · 06-08-2012, 11:01 AM

Normally you would have "physical id" and "core id" lines for each processor in the /etc/cpuinfo file; so you would then know how many real processors and cores you had. The missing lines may indicate a problem with the particular kernel; is this a VPS guest system (perhaps Red Hat)?

Your new host machine has 8 processing units, but my understanding is that the L5420 is a 4 core processor [without hyperthreading, see post by suicidaleggroll below], so there are probably two processors, each with 4 cores (the processors might be both on the same die). The time field of top indicates how much CPU time the processor has used since it started. You need to know how long the process has been running in real time to know if the value is overly high (ie, CPU time divided by real time will give you an idea of the average load of that process).

There is a program x86info (install the package with the same name) which may give you more information.

Sydney · 06-08-2012, 11:59 AM

Intel(R) Xeon(R) CPU L5420 has 4 cores so you have 2 physical CPUs according to cpuinfo.

suicidaleggroll · 06-08-2012, 12:04 PM

Quote:

Originally Posted by Sydney

Intel(R) Xeon(R) CPU L5420 has 4 cores so you have 2 physical CPUs according to cpuinfo.

This logic can only be used because the L5420 does not have hyperthreading. If the CPU supports hyperthreading and its enabled in the BIOS, this logic breaks down because cpuinfo will report two "processors" for each core (eg: a single quad core with hyperthreading will have eight processor entries in cpuinfo). In that case you need to use a combination of the "physical id" and "cores" lines to determine how many actual processor cores the machine has, neither of which are present in the OP's cpuinfo for some reason.