I would like to determine how many instructions it would take for a core to finish a process. Is there a way to determine that? Hence, in a microcontroller you are able to determine the instruction size of functions, I would like to do the same inside Linux. Thanks in advance.
EDIT:[SOLVED] Most suited to my applications was to just
perf stat -p <pid>
and
perf stat <command>
There are various ways to do that:
[]$ readelf -s /usr/lib64/libc.so.6|grep usleep
1542: 00000000000f9090 57 FUNC GLOBAL DEFAULT 12 usleep@@GLIBC_2.2.5
1560: 0000000000000000 0 FILE LOCAL DEFAULT ABS usleep.c
7073: 00000000000f9090 57 FUNC GLOBAL DEFAULT 12 usleep
[]$ objdump -t /usr/lib64/libc.so.6|grep usleep
0000000000000000 l df *ABS* 0000000000000000 usleep.c
00000000000f9090 g F .text 0000000000000039 usleep
[]$ nm -S /usr/lib64/libc.so.6|grep usleep
00000000000f9090 0000000000000039 T usleep
The size in all cases is 0x39 (57) bytes.
If you want the number of instructions of a given function, you can still use objdump:
[]$ objdump -d /usr/lib64/libc.so.6 | perl -ne 'BEGIN { $/="\n\n" }; print if $_ =~ /usleep/;'
...will list the disassembly. For the exact number of instruction you need to subtract to to the line count:
[]$ echo $(objdump -d /lib32/libc.so.6 | perl -ne 'BEGIN { $/="\n\n" }; print if $_ =~ /usleep/;'|wc -l)-2| bc -l
For a dynamic solution you can use perf stat:
[]$ perf stat uptime
10:57:28 up 21 days, 10:30, 4 users, load average: 2.00, 1.98, 2.16
Performance counter stats for 'uptime':
0.719094 task-clock (msec) # 0.802 CPUs utilized
0 context-switches # 0.000 K/sec
0 cpu-migrations # 0.000 K/sec
123 page-faults # 0.171 M/sec
2,297,093 cycles # 3.194 GHz
<not supported> stalled-cycles-frontend
<not supported> stalled-cycles-backend
1,985,122 instructions # 0.86 insns per cycle
389,193 branches # 541.227 M/sec
15,847 branch-misses # 4.07% of all branches
0.000896079 seconds time elapsed
If you run a command a few times you will most likely see that the values fluctuates between runs. Hence, this is no exact science.
