achieving smooth sustained writing to hdd

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I have a video capture app which is streaming video to hdd.

We tried using both write and fwrite, but if we don't fsync() every
few kbs or tune bdflush to very aggressive settings, when kjournald
jumps in we have lost frames.

We're using real time threads on linux 2.4.32 and one of the threads
is continuously sigwait()ing for an interrupt from the capture device
driver.

Why is kjournald getting more priority than that? Actually, we have a
fifo running from the capture thread to the thread that does the
writes, and it doesn't even get filled, which is the opposite of what
we were planning to get: we thought the fifo would absorb the
buffering while the disk was being written.

We're forced to use pio on the disk, so that's definitely dragging us
down...

Any clue?

Thanks a lot,
M

Re: achieving smooth sustained writing to hdd
Kernel 2.6 (especially > 2.6.22) is said to be a lot better for soft
realtime applications like media stuff than Kernel 2.4.x

-Michael

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