Some time ago I mentioned having this performance problem: On Mon, 2008-08-25 at 20:48 +0200, Jens M Andreasen wrote: > For 1024 bytes the transfer will take about 0.2 ms. That is 20% of the > available time if we use a time granularity of a single millisecond. > OTOH this appears to be mostly an intial constant, (much) more data can > be transferred in the exact same amount of time if that is what is > needed.
I have since then updated to kernel 2.6.24.7-rt.17 (and compiled for this systems E1200/Core2) This by itself doubled the throughput, so the upload would be done in approx 100us (or better.) By chance I then tried to run the test back from runlevel 3? This got me down to 25us! ... which also happens to be the target I had been aiming for. A minimal X-setup, as in: $ startx /usr/bin/xterm -- :1 -depth 16 .. yields the same fine results, and so does a lightweight environment like IceWM. But running the (default) Gnome Desktop Environment is consistently quadrupling latencies from main to graphics memory? I have no idea what is going on here, but kicking out gnome seems to solve the problem. /jens _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
