Re: [Quilt-dev] [patch 3/8] tac is not portable

[Gary V. Vaughan]

Jean Delvare wrote:
> Hi Gary,

Salut Jean!

> [Gary V. Vaughan]
>
> > Actually, I'd be even happier if the dependency on tac was dropped in
> > favour of always using the perl snippet (or equivalent portable work
> > alike).
>
> The perl equivalent is about 3 times slower than tac for me, so I don't
> think it is a good idea to just replace it for everyone. Same holds for
> all other compatibility problems BTW, fixing them should preferably not
> cause significant slowdowns for other users.

:-)) LOL

Are you kidding me?  For a file that has maybe 50 lines worst case
and running the tests a dozen times each to make sure we're not just
measuring cache latencies:

$ head -n 50 /var/log/httpd/access_log > input
$ time sh -c "cat input | perl -e 'print reverse <>'
real    0m0.025s
user    0m0.005s
sys     0m0.017s

$ time sh -c "head -n 50 /var/log/httpd/access_log | gtac"
real    0m0.026s
user    0m0.005s
sys     0m0.017s

The timings are completely overwhelmed by the speed of the rest of the
pipeline!

For the sake of easy maintenance of the code, I'd take a hit of even
an extra second of processing time. 1/1000th of a second hardly seems
worth arguing over.

Cheers,
        Gary.
--
Gary V. Vaughan      ())_.  address@hidden,gnu.org}
Research Scientist   ( '/   http://tkd.kicks-ass.net
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Technical Author   `(_~)_   http://sources.redhat.com/autobook

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