Embedded how to locate dead loops or high CPU usage (Linux)

How to locate a dead loop or high CPU usage (Linux)

determine if the CPU is too high

Use top to see if there is high CPU usage

Find a thread

Sort all threads for processes with high CPU usage

PS h-e-o pid,tid,pcpu,cmd--sort=pcpu |grep xxx Obtains the following results, where thread 2909 uses 7.8% of the cpu.2907 2913 0.0./xxx2907 2909 7.8./xxx can also be viewed/ The information in the proc to determine the high CPU thread. 4 columns printed, thread ID, thread name, user time and kernel time (not in the order of precedence) awk ' {print $1,$2,$14,$15} '/proc/2907/task/*/stat Find the call stack

Using the process of GDB attach nmsagent, use info threads in GDB to show all threads

GDB Gdb>attach 2907gdb>info Threads

You can find that the number of 2909 threads is 12, as shown below.

Thread 0xad5f2b70 (LWP 2908) 0x004ef0d7 in mq_timedreceive () from/lib/tls/i686/cmov/librt.so.112 thread 0xad58eb70 (L WP 2909) 0x006e0422 in __kernel_vsyscall () one thread 0xad52ab70 (LWP 2910) 0x006e0422 in __kernel_vsyscall () thread 0xa D4f8b70 (LWP 2911) 0x006e0422 in __kernel_vsyscall () 9 Thread 0xad4c6b70 (LWP 2912) 0x006e0422 in __kernel_vsyscall () 8 Th Read 0xad3feb70 (LWP 2913) 0x004ef0d7 in mq_timedreceive () from/lib/tls/i686/cmov/librt.so.17 Thread 0xace08b70 (LWP 291 4) 0x004ef0d7 in mq_timedreceive () from/lib/tls/i686/cmov/librt.so.16 Thread 0xac607b70 (LWP 2915) 0x006e0422 in __kerne L_vsyscall () 5 thread 0xac5e6b70 (LWP 2916) 0x006e0422 in __kernel_vsyscall () 4 Thread 0xac361b70 (LWP 2917) 0x006e0422 in __kernel_vsyscall () 3 thread 0xac2fdb70 (LWP 2918) 0x006e0422 in __kernel_vsyscall () 2 Thread 0xac1fcb70 (LWP 2919) 0x004 Ef0d7 in Mq_timedreceive () From/lib/tls/i686/cmov/librt.so.1* 1 Thread 0xb78496d0 (LWP 2907) 0x006e0422 in __kernel_vsys Call ()

Use thread to switch threads, use BT to display thread stacks

Gdb>thread GDB>BT

Get the following thread stack

#0 0x006e0422 in __kernel_vsyscall () #1 0x001cca26 in Nanosleep () from/lib/tls/i686/cmov/libc.so.6#2 0X001FC2DC in Uslee P () from/lib/tls/i686/cmov/libc.so.6#3 0x0806b510 in Osptaskdelay () #4 0x0805c710 in Cdispatchtask::nodemsgsendtosock ( ) () #5 0x0805cc74 in Dispatchtaskentry () #6 0x0806a8e9 in Osptasktemplatefunc (void*) () #7 0x00d4780e in Start_thread () fr Om/lib/tls/i686/cmov/libpthread.so.0#8 0x002027ee in Clone () from/lib/tls/i686/cmov/libc.so.6PS + strace Get process ID 21465 ps-e |grep CMU 4996? 00:00:25 cmu_fjga_sp3 21465 pts/5 00:08:10 CMU gets thread time, which accounts for the most CPU epollrecvtask 21581ps-el |grep 2146521465 21579 pts/5 00: 00:00 CamApp21465 21580 pts/5 00:00:00 timerman Task21465 21581 pts/5 00:09:02 EpollRecvTask21465 21582 pts/5 00:00:00 use s Trace-p 21581 getting thread stacks

Embedded how to locate dead loops or high CPU usage (Linux)