Re: faster egit history page and a pure java "gitk"

["Shawn O. Pearce" <spearce@spearce.org>]

"Shawn O. Pearce" <spearce@spearce.org> wrote:
> "Roger C. Soares" <rogersoares@intelinet.com.br> wrote:
> 
> > But it wasn't that fast, it took some minutes to finish building the 
> > whole tree. Also, changing projects (different git repos) makes the cpu 
> > go very high, and what opened fast the first time takes minutes after...

Something else I noticed - the core.packedGit* settings make a
difference on performance.  On Windows XP with Java 6 I am getting
much better performance (200 ms lower running time) by using a much
smaller window size and disabling mmap:

	[core]
		packedGitWindowSize = 8k
		packedGitLimit = 10m
		packedGitMMAP = false

by default jgit is using mmap, as Robin has reported it runs faster
that way for him.  But I have never been able to reproduce that on
Mac OS 10.4/Java 5 or Windows XP/Java 6.  In both systems setting
mmap to false has performed better, even on the initial first set
of hits to the cache where we have to read in the blocks vs. mmap
them.  The ByteBuffer API is just that much slower than accessing
a byte[] directly when shoving it through inflate.  We spend at
least 30% of our time in inflate.

-- 
Shawn.