Vyhledani 0 grepem

Martin `MJ' Mares mj na ucw.cz
Středa Září 6 14:39:29 CEST 2006


Zdravim!

> Zkousel jsem schvalne (na jizlive popichovani kolegu) merit performance
> hit pri pouzity "zbytecne" kocky, a kupodivu je tento hit na mnou
> merenych pripadech 0 (cti nemeritelny), nekdy dokonce -1 (cti
> performance gain). Neprovadel jsem zadna dukladna mereni, proste jen par
> beznych pripadu na ruzne velkych vstupech.

Nevim, jak jste meril Vy, ale mne jednoduchy experiment dava vysledky
presne opacne:

| mares na camellia:/tmp$ seq 1 10000000 >t
| mares na camellia:/tmp$ l t
| -rw-r--r--  1 mares kam 113788806 Sep  6 14:37 t
| mares na camellia:/tmp$ time grep blabla t
| 
| real	0m0.166s
| user	0m0.088s
| sys	0m0.068s
| mares na camellia:/tmp$ time grep blabla t
| 
| real	0m0.164s
| user	0m0.088s
| sys	0m0.068s
| mares na camellia:/tmp$ time grep blabla t
| 
| real	0m0.164s
| user	0m0.084s
| sys	0m0.076s
| mares na camellia:/tmp$ time cat t | grep blabla 
| 
| real	0m0.298s
| user	0m0.124s
| sys	0m0.172s
| mares na camellia:/tmp$ time cat t | grep blabla 
| 
| real	0m0.296s
| user	0m0.080s
| sys	0m0.212s
| mares na camellia:/tmp$ time cat t | grep blabla 
| 
| real	0m0.296s
| user	0m0.092s
| sys	0m0.200s
| mares na camellia:/tmp$ 

Tedy kocici verze je konsistentne 1.8-krat pomalejsi.

				Have a nice fortnight
-- 
Martin `MJ' Mares   <mj na ucw.cz>   http://atrey.karlin.mff.cuni.cz/~mj/
Faculty of Math and Physics, Charles University, Prague, Czech Rep., Earth
"This quote has been selected randomly. Really." -- M. Ulrichs


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