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On Tue, Oct 16, 2007 at 03:14:12AM +0100, Steve Long wrote: |
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> Gilles Dartiguelongue wrote: |
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> > I haven't reread the fine mans for a while but iirc, + could lead you to |
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> > hit the argument buffer limit of your shell. xargs has --max-args to get |
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> > around that and is also way faster than any -exec variant (at least |
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> > that's what the bench I did on a PIV2.6Ghz showed me about 4 months ago) |
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> > |
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> It doesn't: find will just execute the command as many times as needed (each |
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> time with an argument length maximally less than ARG_MAX. Well, it did when |
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> we tested this a couple of months ago.) So it's optimal in that sense. I |
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> have no idea on the timing measurements, but I don't like pipes and |
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> subshells as a rule (externals are bad enough!;>) It'd be interesting to |
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> see measurements over 100000 loops with long argument lists requiring |
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> multiple invocations per pass, I suppose. |
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Here's a quick benchmark: |
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% \ |
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repeat 3 \time find -name '*.ebuild' | xargs cat >/dev/null; echo; \ |
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repeat 3 \time find -name '*.ebuild' -exec cat {} ';' >/dev/null; echo; \ |
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repeat 3 \time find -name '*.ebuild' -exec cat {} '+' >/dev/null |
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66.28 real 0.77 user 4.71 sys |
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30.95 real 0.76 user 4.73 sys |
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30.08 real 0.76 user 4.67 sys |
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|
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174.72 real 18.10 user 112.92 sys |
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208.69 real 18.07 user 117.05 sys |
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173.64 real 18.10 user 110.79 sys |
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|
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62.61 real 1.26 user 10.88 sys |
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54.98 real 1.25 user 10.46 sys |
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41.84 real 1.25 user 10.00 sys |
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the third variant doesn't get any faster than on the last line. |
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( tested in zsh, with bsd time and gnu find ) |
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-- Elias |
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