[PATCH STABLE] log: restore cache used by --copies

[Greg Ward]

On 25 February 2012, Patrick Mezard said:
> A couple of indicative timings of "hg log --copies", before and after:
> 
> hg:                       44s /     5s
> mozilla --limit 10000:  3m51s /  2m32s
> mozilla:               23m46s / 12m23s
> 
> I do not know any good tool to trace memory consumption of these runs for
> comparisons. Watching the full mozilla run in top, the process did not seem to
> misbehave.

The GNU version of "time" can print peak memory use with a custom
format string. E.g.

  /usr/bin/time -f "%E sec, %M kB" hg tip

reports

  0:00.45 sec, 10236 kB

when run against the Mercurial repo (16k revisions), but 

  0:00.92 sec, 37328 kB

on a repo with 126k revisions. I think it's reporting the same numbers
as "top", but without relying on sampling the system at just the right
instant.

        Greg
-- 
Greg Ward                                http://www.gerg.ca/
Monday is an awful way to spend one seventh of your life.