After running a cpu-consuming program(pid is 7332) under a 32-bit x86 SMP linux for 80 days，I find utime and stime field in /proc/7332/stat stop increase, but the program seems still running right.
The wrong value in /proc/7332/stat cause 'top' and 'ps aux' output wrong cpu % usage. I guess this issue may happens when the sum of utime + stime is close to 0xffffffff . Here is some logs below: # cat /proc/7332/stat 7332 (prog) R 7330 1173 1173 0 -1 4202496 1936595 0 0 0 2133359497 2133437350 0 0 15 -5 4 0 264907 2043727872 139368 4294967295 134512640 141884576 3215417504 3215416688 134589605 0 0 16783367 512 4294967295 0 0 17 3 0 0 0 0 0 # cat /proc/7332/stat 7332 (prog) R 7330 1173 1173 0 -1 4202496 1936595 0 0 0 2133359497 2133437350 0 0 15 -5 4 0 264907 2043727872 139368 4294967295 134512640 141884576 3215417504 3215416688 134588046 0 0 16783367 512 4294967295 0 0 17 3 0 0 0 0 0 # cat /proc/7332/stat 7332 (prog) R 7330 1173 1173 0 -1 4202496 1936595 0 0 0 2133359497 2133437350 0 0 15 -5 4 0 264907 2043727872 139368 4294967295 134512640 141884576 3215417504 3215416688 134588042 0 0 16783367 512 4294967295 0 0 17 3 0 0 0 0 0 # uname -a Linux localhost 2.6.39-gentoo-r3 #50 SMP PREEMPT Sat Jun 9 11:34:08 CST 2012 i686 Intel(R) Core(TM) i3-2120 CPU @ 3.30GHz GenuineIntel GNU/Linux # cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 42 model name : Intel(R) Core(TM) i3-2120 CPU @ 3.30GHz stepping : 7 cpu MHz : 3292.630 cache size : 3072 KB physical id : 0 siblings : 4 core id : 0 cpu cores : 2 apicid : 0 initial apicid : 0 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 13 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 nx rdtscp lm constant_tsc arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt xsave avx lahf_lm arat epb xsaveopt pln pts dts tpr_shadow vnmi flexpriority ept vpid bogomips : 6585.26 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 42 model name : Intel(R) Core(TM) i3-2120 CPU @ 3.30GHz stepping : 7 cpu MHz : 3292.630 cache size : 3072 KB physical id : 0 siblings : 4 core id : 1 cpu cores : 2 apicid : 2 initial apicid : 2 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 13 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 nx rdtscp lm constant_tsc arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt xsave avx lahf_lm arat epb xsaveopt pln pts dts tpr_shadow vnmi flexpriority ept vpid bogomips : 6584.19 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: processor : 2 vendor_id : GenuineIntel cpu family : 6 model : 42 model name : Intel(R) Core(TM) i3-2120 CPU @ 3.30GHz stepping : 7 cpu MHz : 3292.630 cache size : 3072 KB physical id : 0 siblings : 4 core id : 0 cpu cores : 2 apicid : 1 initial apicid : 1 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 13 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 nx rdtscp lm constant_tsc arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt xsave avx lahf_lm arat epb xsaveopt pln pts dts tpr_shadow vnmi flexpriority ept vpid bogomips : 6584.18 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: processor : 3 vendor_id : GenuineIntel cpu family : 6 model : 42 model name : Intel(R) Core(TM) i3-2120 CPU @ 3.30GHz stepping : 7 cpu MHz : 3292.630 cache size : 3072 KB physical id : 0 siblings : 4 core id : 1 cpu cores : 2 apicid : 3 initial apicid : 3 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 13 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 nx rdtscp lm constant_tsc arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf pni pclmulqdq dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm sse4_1 sse4_2 popcnt xsave avx lahf_lm arat epb xsaveopt pln pts dts tpr_shadow vnmi flexpriority ept vpid bogomips : 6584.19 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: #top top - 15:39:34 up 80 days, 21:31, 0 users, load average: 3.91, 3.70, 3.67 Tasks: 102 total, 4 running, 98 sleeping, 0 stopped, 0 zombie Cpu(s): 78.8%us, 2.2%sy, 0.0%ni, 18.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 8145408k total, 3136024k used, 5009384k free, 35956k buffers Swap: 0k total, 0k used, 0k free, 458228k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 7332 root 15 -5 1949m 544m 20m R 0 6.8 711132:48 prog # ps aux|grep 7332 root 7332 610 6.8 1209396 557472 ? R<l Jul10 711132:48 /root/prog # ps -ef|grep 7332 nos 1438 8563 0 15:41 pts/3 00:00:00 grep 7332 nos 7332 7330 99 Jul10 ? 493-20:12:48 /root/prog -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
