Re: High scheduler wake up times

[Shawn Bohrer]

On Sat, Jan 30, 2010 at 03:56:40PM -0800, Arjan van de Ven wrote:
> On Sat, 30 Jan 2010 17:45:51 -0600
> Shawn Bohrer <shawn.bohrer@xxxxxxxxx> wrote:
> 
> > Hello,
> > 
> > Currently we have a workload that depends on around 50 processes that
> > wake up 1000 times a second do a small amount of work and go back to
> > sleep.  This works great on RHEL 5 (2.6.18-164.6.1.el5), but on recent
> > kernels we are unable to achieve 1000 iterations per second.  Using
> > the simple test application below on RHEL 5 2.6.18-164.6.1.el5 I can
> > run 500 of these processes on and still achieve 999.99 iterations per
> > second.  Running just 10 of these processes on the same machine with
> > 2.6.32.6 produces results like:
> > 
> > ...
> > Iterations Per Sec: 905.659667
> > Iterations Per Sec: 805.099068
> > Iterations Per Sec: 925.195578
> > Iterations Per Sec: 759.310773
> > Iterations Per Sec: 702.849261
> > Iterations Per Sec: 782.157292
> > Iterations Per Sec: 917.138031
> > Iterations Per Sec: 834.770391
> > Iterations Per Sec: 850.543755
> > ...
> > 
> > I've tried playing with some of the cfs tunables in /proc/sys/kernel/
> > without success.  Are there any suggestions on how to achieve the
> > results we are looking for using a recent kernel?
> 
> I'll play a bit, but I wonder idly what kind of machine this is on ?
> (number and types of cpus)

$ cat /proc/cpuinfo
processor	: 0
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 1
siblings	: 8
core id		: 0
cpu cores	: 4
apicid		: 16
initial apicid	: 16
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5852.40
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           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 0
siblings	: 8
core id		: 0
cpu cores	: 4
apicid		: 0
initial apicid	: 0
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.05
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           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 1
siblings	: 8
core id		: 1
cpu cores	: 4
apicid		: 18
initial apicid	: 18
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.04
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           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 0
siblings	: 8
core id		: 1
cpu cores	: 4
apicid		: 2
initial apicid	: 2
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.05
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:

processor	: 4
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 1
siblings	: 8
core id		: 2
cpu cores	: 4
apicid		: 20
initial apicid	: 20
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.04
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:

processor	: 5
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 0
siblings	: 8
core id		: 2
cpu cores	: 4
apicid		: 4
initial apicid	: 4
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.05
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:

processor	: 6
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 1
siblings	: 8
core id		: 3
cpu cores	: 4
apicid		: 22
initial apicid	: 22
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.04
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:

processor	: 7
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 0
siblings	: 8
core id		: 3
cpu cores	: 4
apicid		: 6
initial apicid	: 6
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.05
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:

processor	: 8
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 1
siblings	: 8
core id		: 0
cpu cores	: 4
apicid		: 17
initial apicid	: 17
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.04
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:

processor	: 9
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 0
siblings	: 8
core id		: 0
cpu cores	: 4
apicid		: 1
initial apicid	: 1
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.05
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:

processor	: 10
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 1
siblings	: 8
core id		: 1
cpu cores	: 4
apicid		: 19
initial apicid	: 19
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.04
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:

processor	: 11
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 0
siblings	: 8
core id		: 1
cpu cores	: 4
apicid		: 3
initial apicid	: 3
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.05
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:

processor	: 12
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 1
siblings	: 8
core id		: 2
cpu cores	: 4
apicid		: 21
initial apicid	: 21
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.04
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:

processor	: 13
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 0
siblings	: 8
core id		: 2
cpu cores	: 4
apicid		: 5
initial apicid	: 5
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.05
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:

processor	: 14
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 1
siblings	: 8
core id		: 3
cpu cores	: 4
apicid		: 23
initial apicid	: 23
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.05
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:

processor	: 15
vendor_id	: GenuineIntel
cpu family	: 6
model		: 26
model name	: Intel(R) Xeon(R) CPU           X5570  @ 2.93GHz
stepping	: 5
cpu MHz		: 2926.203
cache size	: 8192 KB
physical id	: 0
siblings	: 8
core id		: 3
cpu cores	: 4
apicid		: 7
initial apicid	: 7
fpu		: yes
fpu_exception	: yes
cpuid level	: 11
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 syscall nx rdtscp lm constant_tsc arch_perfmon pebs bts rep_good xtopology tsc_reliable nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida tpr_shadow vnmi flexpriority ept vpid
bogomips	: 5851.05
clflush size	: 64
cache_alignment	: 64
address sizes	: 40 bits physical, 48 bits virtual
power management:



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