Bug #663
closedBenchmark.measure outputs different result when executed using command line "ruby -e ..."
Description
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I've tested it on :
- ruby 1.8.6 (2008-03-03 patchlevel 114) [i686-linux]
- ruby 1.8.5 (2006-08-25) [i386-linux]
Sorry, I've not tested it against 1.9 and 1.8.7.
[artem@dev bm_test]$ cat a.c
int main() {
int i = 0, k = 0, n = 1000000000;
for(i = 0 ; i< n; i++){ k += i*i; }
return k;
}
[artem@dev bm_test]$ make a
cc a.c -o a
[artem@dev bm_test]$ ruby -rbenchmark -e "puts Benchmark.measure{ ./a
}"
0.000000 0.000000 0.000000 ( 0.000011)
[artem@dev bm_test]$ echo 'puts Benchmark.measure{ ./a
}' > b.rb
[artem@dev bm_test]$ cat b.rb
puts Benchmark.measure{ ./a
}
[artem@dev bm_test]$ ruby -rbenchmark b.rb
0.000000 0.000000 4.660000 ( 4.652781)
Bugs:
- "ruby -e" : "total" is zero
- "ruby -e" : "real" is too small (should be ~ 4 seconds)
- "ruby" : "total" is not equal to "user" + "system" in the last example.
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Updated by mame (Yusuke Endoh) almost 16 years ago
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Hi,
Thank you for your report.
2008/10/19 Artem Vorozhtsov redmine@ruby-lang.org:
Bugs:
- "ruby -e" : "total" is zero
- "ruby -e" : "real" is too small (should be ~ 4 seconds)
I think ./a
is executed by your shell. If so, it's not a bug of ruby.
$ ruby19 -rbenchmark -e "puts Benchmark.measure { ./a
}"
0.000000 0.000000 0.000000 ( 0.000000)
$ ruby19 -rbenchmark -e 'puts Benchmark.measure { ./a
}'
0.000000 0.000000 7.540000 ( 7.540114)
- "ruby" : "total" is not equal to "user" + "system" in the last example.
While "user" and "system" show CPU time that only the process comsumed,
"total" shows CPU time that both the process and its children consumed.
I don't know whether it is intended.
You can see the user and system CPU time that both consumed in the
following way:
$ ruby19 -rbenchmark -e 'puts Benchmark.measure { ./a
}.format("%10.6U %10.6Y %10.6t %10.6r\n")'
6.460000 0.000000 6.460000 ( 6.460097)
--
Yusuke ENDOH mame@tsg.ne.jp
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Updated by shyouhei (Shyouhei Urabe) almost 16 years ago
- Status changed from Open to Rejected
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=end
Updated by greck (Artem Vorozhtsov) almost 16 years ago
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2008/10/19 Yusuke ENDOH mame@tsg.ne.jp:
Hi,
Thank you for your report.
2008/10/19 Artem Vorozhtsov redmine@ruby-lang.org:
Bugs:
- "ruby -e" : "total" is zero
- "ruby -e" : "real" is too small (should be ~ 4 seconds)
I think
./a
is executed by your shell. If so, it's not a bug of ruby.$ ruby19 -rbenchmark -e "puts Benchmark.measure {
./a
}"
0.000000 0.000000 0.000000 ( 0.000000)$ ruby19 -rbenchmark -e 'puts Benchmark.measure {
./a
}'
0.000000 0.000000 7.540000 ( 7.540114)
:)
I'm really sorry.
- "ruby" : "total" is not equal to "user" + "system" in the last example.
While "user" and "system" show CPU time that only the process comsumed,
"total" shows CPU time that both the process and its children consumed.
I don't know whether it is intended.You can see the user and system CPU time that both consumed in the
following way:$ ruby19 -rbenchmark -e 'puts Benchmark.measure {
./a
}.format("%10.6U %10.6Y %10.6t %10.6r\n")'
6.460000 0.000000 6.460000 ( 6.460097)--
Yusuke ENDOH mame@tsg.ne.jp
Thanks!
Then documentation should be fixed.
At http://www.ruby-doc.org/stdlib/libdoc/benchmark/rdoc/classes/Benchmark.html
one could read
"This report shows the user CPU time, system CPU time, the sum of the
user and system CPU times, and the elapsed real time. The unit of time
is seconds. "
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