How to diagnose a python process chewing CPU in li

Question

My python process at certain point in automated scripts starts chewing CPU on Linux based System (Ubuntu). I’m trying to debug this issue in GDB. I'm fairly new to GDB. Are there any GDB commands to give information on which thread is using most of the cpu. Looking at the thread stack doesn't really give that away.

On windows windbg world the command '!runaway' did give the info on time consumed by each thread in a process. Do we've an equivalent command here ? Any other suggestions to debug issue ?

Answer 1

One possible solution is to use the command top with the option to display all threads:

> top -H

The tasks will be sorted by CPU usage by default.

Alternate solutions can be found in the previous thread here.

Answer 2

Just to clarify all the steps required to diagnose this issue. (thanks everyone for postings) :

Following command shows the list of process with their CPU / Memory usage :

ps auxf

Following command gives the list of all threads of a process sorted with CPU usage.

top -H -p [PID]

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

1654 root 20 0 1416m 1.2g 24m t 100 36.8 21:26.23 python

1687 root 20 0 1416m 1.2g 24m t 0 36.8 0:05.07 python

Thread 1654 is chewing CPU. Attach gdb to the process

gdb /path/of/process [pid]

Following command in gdb to get list of threads

(gdb) info threads

2 Thread 0xa7bffb40 (LWP 20736) "python" 0xb7736424 in __kernel_vsyscall ()

1 Thread 0xb73a56c0 (LWP 1654) "python" 0xb7736424 in __kernel_vsyscall ()

in gdb switch to the thread to check its stack.

(gdb) thread 1

(gdb) bt