* perf: comparing "CPU performance / CPU impact" of two binaries?
@ 2016-12-19 15:32 Tomasz Chmielewski
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From: Tomasz Chmielewski @ 2016-12-19 15:32 UTC (permalink / raw)
To: linux-perf-users
Let's say I have two binaries which convert complex data from one format
to another.
I will run them on a busy server at low priority and I don't really care
if one is faster than the other - I want to know which of them will have
lower "CPU impact" to perform the same task.
binary_1:
26879408.172126 task-clock:u (msec) # 0.709 CPUs
utilized
0 context-switches:u # 0.000 K/sec
0 cpu-migrations:u # 0.000 K/sec
1142192473 page-faults:u # 0.042 M/sec
81241884199345 cycles:u # 3.022 GHz
(83.59%)
65593453047217 stalled-cycles-frontend:u # 80.74% frontend
cycles idle (83.59%)
34800591044061 stalled-cycles-backend:u # 42.84% backend
cycles idle (67.09%)
98783244945290 instructions:u # 1.22 insn per
cycle
# 0.66 stalled
cycles per insn (83.64%)
18250463170335 branches:u # 678.976 M/sec
(83.60%)
169450790563 branch-misses:u # 0.93% of all
branches (83.59%)
37911.679793230 seconds time elapsed
binary_2:
33134123.016486 task-clock:u (msec) # 1.071 CPUs
utilized
0 context-switches:u # 0.000 K/sec
0 cpu-migrations:u # 0.000 K/sec
1947142971 page-faults:u # 0.059 M/sec
105227191042973 cycles:u # 3.176 GHz
(83.69%)
80721331715962 stalled-cycles-frontend:u # 76.71% frontend
cycles idle (83.69%)
46245245856602 stalled-cycles-backend:u # 43.95% backend
cycles idle (67.25%)
140459525725760 instructions:u # 1.33 insn per
cycle
# 0.57 stalled
cycles per insn (83.93%)
9187630340020 branches:u # 277.286 M/sec
(83.70%)
112107883833 branch-misses:u # 1.22% of all
branches (83.69%)
30949.033426941 seconds time elapsed
As you can see, binary_1 was executing for 37911 seconds, and binary_2
for 30949 seconds.
On the other hand, binary_2 used more cycles and instructions.
Because I will be running it on a busy server, I think that binary_1
will have lower impact on the CPU (and, other tasks). Is my reasoning
correct?
Tomasz Chmielewski
https://lxadm.com
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2016-12-19 15:32 perf: comparing "CPU performance / CPU impact" of two binaries? Tomasz Chmielewski
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