[KimDaBa] Profiling Kimdaba startup
davidf at sjsoft.com
Wed Jan 5 07:58:04 CET 2005
Jody Harris wrote:
> A humble thought on making start time shorter:
> One way to compress the load time would be to compress the xml file.
> Because of XML's inherent "spaciness," there is some (large)
> percentage of the file that is read from disk, then "tossed" (white
> spaces, tags, etc) as data is put into an in-memory data structure.
> Since much of this information is highly redundant, you should be able
> to gain a high amount of compression on the data even at the default
> (6?) compression level. Time save reading the data should more than
> offset time decompressing the data.
> Some tests:
> My original file: 5743 images, 3.2MB
> Copy index.xml from A to B:
> bigpig@~ $ time cp photo/index.xml tmp
> real 0m0.194s
> user 0m0.001s
> sys 0m0.028s
> Compression step with gzip, default settings:
> bigpig@~ $ time gzip tmp/index.xml
> real 0m0.107s
> user 0m0.092s
> sys 0m0.006s
> Resulting compressed file: 209KB (!)
> Make a copy of the compressed file with gzip:
> bigpig@~ $ time cp tmp/index.xml.gz tmp/index.xml.gz.2
> real 0m0.006s
> user 0m0.002s
> sys 0m0.003s
> Unzip the compressed file:
> bigpig@~ $ time gzip -d tmp/index.xml.gz
> real 0m0.034s
> user 0m0.020s
> sys 0m0.010s
> Granted those are "one-time tests." to get a good benchmark, you'd
> need to run each step enough times to get a system average, but if
> these numbers are even close, we're looking at 0.040s (real) vs 0.194s
> (real), a savings of ~79%.
> Jesper? What do you think? Robert? Michael? Others?
Most of the time isn't reading the file from disk etc but parsing the xml...
PS I think you forgot to cc the list.
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