Garrett Cooper wrote:
Tim Kientzle wrote:
-I tried ... buffering ... the +CONTENTS file parsing function,
and the
majority of the time it yielded good results ....
One approach I prototyped sometime back was to use
libarchive in pkg_add as follows:
* Open the archive
* Read +CONTENTS directly into memory (it's
guaranteed to always be first in the archive)
* Parse all of +CONTENTS at once
* Continue scanning the archive, disposing
of each file as it appears in the archive.
Based on my experience with this, I would
suggest you just read all of +CONTENTS
directly into memory at once and parse
the whole thing in a single shot.
fopen(), then fstat() to get the size,
then allocate a buffer and read the whole
thing, then fclose(). You can then
parse it all at once.
As a bonus, your parser then becomes a nice
little bit of reusable code that reads
a block of memory and returns a structure describing
the package metadata.
Tim Kientzle
I'm not 100% sure because I'm not comparing apples (virtual disk on
desktop via VMware) to apples (real disk on server), but I'm showing a
2.5-fold speedup after adding the simple parser:
Virtual disk:
4.42 real 1.37 user 1.47 sys
Real disk:
10.26 real 5.36 user 0.99 sys
I'll run a battery of tests just to ensure whether or not that's the
case.
Be back with results in a few more days.
-Garrett
Hello,
As promised, here are some results for my work:
By modifying the parser and heuristics in plist_cmd I appear to have
decreased all figures (except plist_cmd, which I will note later) from
their original values to much lower values. The only drawback is that I
appear to have stimulated a bug with either malloc'ing memory,
printf/vargs, or transferring large amounts of data via pipes where some
of my debug messages are making it into plist_cmd(..) from
obtainbymatch(..), which represents the the 3-fold increase in reported
plist_cmd(..) iterations.
I'm going to try replacing the debug commands with standard print
statements wherever possible, then replace all tar commands with
libarchive APIs, and see if the problem solves itself.
Notes:
1. This sample is based off x11-libs/atk.
2. It isn't the final set of results.
3. Graphs coming soon (need to simulate values in Excel on work machine
and convert to screenshots later on when I have a break -- thinking
around noon). I'll repost when I have them available.
4. CSV files available at:
http://students.washington.edu/youshi10/posted/atk-results.tgz.
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