The usage of videobuf-vmalloc allows to cleanup em28xx logic.
Also, it reduced its size by about 5.42% on i386 arch (and about 7.5% on x86_64):
39113 4876 40 44029 abfd old/em28xx.ko
36731 4868 40 41639 a2a7 /home/v4l/master/v4l/em28xx.ko
Also, the preliminary tests, made on a single core 1.5 MHz Centrino showed
that CPU usage reduced from 42%-75% to 28%-33% (reports from "top") command.
A test with time command presented an even better result:
This is the performance tests I did, running code_example to get 1,000 frames
@29.995 Hz (about 35 seconds of stream), tested on a i386 machine, running at
1,5GHz:
The old driver:
$ time -f "%E: %Us User time, %Ss Kernel time, %P CPU used" ./capture_example
0:34.21: 8.22s User time, 25.16s Kernel time, 97% CPU used
The videobuf-based driver:
$ time -f "%E: %Us User time, %Ss Kernel time, %P CPU used" ./capture_example
0:35.36: 0.01s User time, 0.05s Kernel time, 0% CPU used
Conclusion:
The time consumption to receive the stream where reduced from about 33.38
seconds to 0.05 seconds.
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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