Miscellaneous improvements to "jar".

Martin Buchholz martinrb at google.com
Fri Jun 26 16:04:18 UTC 2009

Removing one layer of BufferedInputStream
in my change saves one bulk copy per file.
And reusing the same buffer saves on cache misses
and GC.  But bulk copy is actually very fast,
(especially as memory is becoming more like disk),
so the win is relatively small.

I would be surprised if you could get more than
the 10-20% that I've gotten with this change,
by using direct buffers.


On Fri, Jun 26, 2009 at 08:47, Xueming Shen <Xueming.Shen at sun.com> wrote:

> I do have a "prototype implementation" that uses buffer based read/write on
> Jar/ZipFile, it
> is not that "much" faster as you would have expected (basically the gain of
> using direct buffer
> comes from saving one or two memory copy of the content,  which is very
> faster, compared to
> the "real hard" work of moving bits from harddisk to memory). While it's
> still something
> worth doing,  but definitely not a high priority for now, yes, it's on the
> list.
> Sherman
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