Hi all, this post is about some benchmarks we did on Nokia’s N800 device to measure the performance of XShmPutImage on this hardware.
I’ve been working on the QEdje project and, while studying possible optimizations, our team was interested in measuring whether we could benefit from using MIT’s X11 shared memory extensions. Among other tests, I managed to run x11perf on the N800.
A simple patch was needed before cross-compiling it. This because this app has a hard-coded window size of 600×600 pixels, more than what’s available in our 800×480 screen, thus leading to a X error message, complaining about get screen parameters.
I also reduced the square side size from 500 to 400 pixels in the XShmPutImage and XPutImage tests (shmput500 and putimage500).
The results were absolutely favorable to the use of the shared memory extension as you can see below:
./x11perf –shmput500 -sync
800 reps @ 8.6566 msec ( 116.0/sec)
./x11perf -putimage500 -sync
360 reps @ 14.8336 msec ( 67.4/sec)
For those willing to reproduce the tests, the patch is available below and should apply cleanly to x11perf 1.5.