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Re: Why does not rgrep use "grep -r"?
From: |
David Kastrup |
Subject: |
Re: Why does not rgrep use "grep -r"? |
Date: |
Sun, 04 Nov 2007 19:59:28 +0100 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/23.0.50 (gnu/linux) |
Eli Zaretskii <address@hidden> writes:
>> From: David Kastrup <address@hidden>
>> Cc: Miles Bader <address@hidden>, address@hidden, address@hidden,
>> address@hidden
>> Date: Sat, 03 Nov 2007 10:43:03 +0100
>>
>> Totally warm cache:
>>
>> address@hidden:/usr/local/texlive/2007$ time find -name \*.tex|xargs grep
>> snort
>> ./texmf-dist/source/latex/ae/aesample.tex:and whooping and sneezing and
>> snorting, that I could not hear myself think for
>>
>> real 0m0.974s
>> user 0m0.372s
>> sys 0m0.536s
>> address@hidden:/usr/local/texlive/2007$ time grep -r --include=\*.tex snort
>> .
>> ./texmf-dist/source/latex/ae/aesample.tex:and whooping and sneezing and
>> snorting, that I could not hear myself think for
>>
>> real 0m1.225s
>> user 0m0.376s
>> sys 0m0.764s
>> [...]
>> On a warm cache, it is pretty much the same.
>
> Perhaps for the Linux filesystem, it is. It looks as it's quite
> different on Windows:
>
> With warm cache:
>
> timep grep -r snort d:/gnu/gdb-CVS/src/gdb > nul
>
> real 00h00m03.171s
> user 00h00m00.234s
> sys 00h00m02.312s
>
> timep find d:/gnu/gdb-CVS/src/gdb -name "*.c" | xargs grep snort > nul
>
> real 00h00m03.921s
> user 00h00m00.015s
> sys 00h00m00.015s
>
> That's a 20% difference in elapsed time (the fact that user and sys
> are zero is just an artefact of the timep command implementation on
> Windows).
What sense is there in using commands doing something quite different?
The first searches all files, the second just a subset.
> With cold cache:
>
> timep grep -r snort d:/gnu/gdb-CVS/src/gdb > nul
>
> real 00h00m15.531s
> user 00h00m00.328s
> sys 00h00m03.140s
>
> timep find d:/gnu/gdb-CVS/src/gdb -name "*.c" | xargs grep snort > nul
>
> real 00h00m13.687s
> user 00h00m00.015s
> sys 00h00m00.078s
>
> That's 11%, a much smaller gain, and in the other direction.
How is this the other direction? You mean the other direction from your
first test rather than the test using GNU/Linux?
--
David Kastrup, Kriemhildstr. 15, 44793 Bochum
- Re: Why does not rgrep use "grep -r"?, (continued)
- Re: Why does not rgrep use "grep -r"?, Miles Bader, 2007/11/02
- Re: Why does not rgrep use "grep -r"?, Andreas Schwab, 2007/11/02
- Re: Why does not rgrep use "grep -r"?, Lennart Borgman (gmail), 2007/11/02
- Re: Why does not rgrep use "grep -r"?, Miles Bader, 2007/11/02
- Re: Why does not rgrep use "grep -r"?, Lennart Borgman (gmail), 2007/11/02
- Re: Why does not rgrep use "grep -r"?, Miles Bader, 2007/11/02
- Re: Why does not rgrep use "grep -r"?, Eli Zaretskii, 2007/11/03
- Re: Why does not rgrep use "grep -r"?, David Kastrup, 2007/11/03
- Re: Why does not rgrep use "grep -r"?, Eli Zaretskii, 2007/11/03
- Re: Why does not rgrep use "grep -r"?, Lennart Borgman (gmail), 2007/11/03
- Re: Why does not rgrep use "grep -r"?,
David Kastrup <=
- Re: Why does not rgrep use "grep -r"?, Eli Zaretskii, 2007/11/05
- Re: Why does not rgrep use "grep -r"?, Ken Raeburn, 2007/11/03
- Re: Why does not rgrep use "grep -r"?, Eli Zaretskii, 2007/11/03
- Re: Why does not rgrep use "grep -r"?, Eli Zaretskii, 2007/11/03
Re: Why does not rgrep use "grep -r"?, Stefan Monnier, 2007/11/03
Re: Why does not rgrep use "grep -r"?, Kim F. Storm, 2007/11/03