Xpra: Ticket #67: mmap improvements: zero-copy, avoid wrap-around, memcopy, mmap.ACCESS_COPY

mmap is fast but can be made faster:

Fri, 06 Jan 2012 09:59:38 GMT - Antoine Martin: attachment set

patch for measuring the improvement using zerocopy

Fri, 06 Jan 2012 10:16:35 GMT - Antoine Martin: owner, status changed

Part 1: zero-copy The patch above allows us to measure the zero-copy case against the standard code (one must add and False to make it go through the non zero-copy case for non-split areas). Some numbers with a 1024x1024 glxgears on a fast system (ignoring small screen updates which skew the number due to the high overhead of method calls compared to the actual time spent preparing the data - which means the benefit is less, almost negligible, when used on small pixel buffers):

So the benefit is in the 10% to 50% range, average around 20%.

Merged in r400

Fri, 06 Jan 2012 10:57:58 GMT - Antoine Martin: priority, component, milestone changed

Part 2: avoid wrapping around Done in r401, which also adds diagrams to show how the mmap transfers work.

Mon, 20 Feb 2012 19:32:52 GMT - Antoine Martin: milestone changed

Fri, 04 May 2012 09:57:33 GMT - Antoine Martin: milestone changed

This is good enough for now, the only features left to consider are:

Tue, 16 Jul 2013 06:02:16 GMT - Antoine Martin: status changed

We now use XShm (see #345).

Tue, 16 Jul 2013 06:02:54 GMT - Antoine Martin: status changed; resolution set

Mon, 19 May 2014 12:36:14 GMT - Antoine Martin: milestone changed

(setting correct milestone the work was completed in)

Sat, 23 Jan 2021 04:44:38 GMT - migration script:

this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/67