Security question?

[Roland Mainz]

Jim Gettys wrote:
> 
> > It would be interesting to see if the results in this paper can be improved
> > upon by using linux futexes rather than the Unix socket for synchronization.
> > The implementation referred to in this paper is still available on a branch
> > of the DRI xc tree, if anyone feels like some archaeology.
> 
> Not to mention the fact that Unix domain sockets on Linux are really,
> *really* fast;

... which is a myth. It's fast but shared memory can usually beat it
without problems. You save at least one data copy (which is important
when you shuffle around large amounts of image/texture/etc. data) and
don't have to split the data (there's the BIGREQUESTS extension but Xsun
doesn't support it right now). And in the case of a shared memory X
transport you can even skip all the weired endian tests and copying -
you usually write into the shared memory area and let the Xserver do the
rest.

[snip]
> Some serious performance work is in order, and not just the
> "x11perf" flavor micro optimization work either.

Using "x11perf" for benchmarking is more or less useless these days as
it's mixture of protocol requests doesn't reflect how applications use
it. For example if you measure Sun's shared memory transport with
"x11perf" you only get a one-digit percent improvement - but when you
test it with Mozilla's DHTML perf. tests then you get a perf.
improvement in the three-digit percent range (!!!; this is the reason
why Mozilla/Firefox use the Xsun shared memory transport by default),
assuming you use the default buffer size - which is far too small for
todays applications, incresing it makes applications even faster.

----

Bye,
Roland

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