Hello wm4,
Thursday, November 5, 2015, 3:42:30 PM, you wrote:
w> On Thu, 5 Nov 2015 12:49:50 +0100
w> "Sven Dueking" <s...@nablet.com> wrote:
>> > > + } else if (ret == MFX_WRN_DEVICE_BUSY) {
>> > > + av_usleep(500);
>> >
>> > What. Use proper event-based waiting.
It is not possible.
>>
>> That´s the same behavior as we have in the qsv encoder and decoder.
>> And as far as I know this is how Intel recommends to handle this.
w> That's just ridiculous. Can you send some hate-mail to Intel and tell
w> them what a bad idea this is? Half a millisecond is an eternity for a
w> CPU. What if the device is blocked only for 10 microseconds? Then it
w> will waste time by spending 490 microseconds idly.
1. Please remember we use GPU, not CPU.
2. 500us means that even we will get MFX_WRN_DEVICE_BUSY at every frame we
will able to achieve ~2000fps performance. It looks enough
performance level for any practical applications.
3. In real life MFX_WRN_DEVICE_BUSY does appear when GPU really busy by
other tasks. So nothing bad will appear if one thread/process will sleep for
500us to make another thread complete its work.
w> Software engineers recognized that polling is a bad idea half a century
w> ago. Why can't Intel do this right?
May be because it is complex to organize event-polling when calculations
performs in GPU?
w> Or does MFX have some sort of async mode that works without polling?
Does NOT. I'm sorry but we forced to use this way, since it is by QSV
design.
--
Best regards,
Ivan mailto:ivan.us...@nablet.com
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