Brian Buhrow <buhrow%nfbcal.org@localhost> writes: > Hello. Another question about the read ahead and write behind code > in ugen(4). It seems that if a write call comes in with a block of data, > and a second write call comes in with a second block of data before the > first block of data has been written to the USB device, the two blocks of > data get concatinated into one USB xfer to the device. Questions: I have no recollection of intending that it work this way. The point was to avoid the latency of write(2) followed by an xfrer followed by notifying the user process followed by another write(2), as with a USRP (1st gen) without the RAWB code, we were only able to operate at 16 MB/s transfer rates rather than 32 MB/s. (All details slightly fuzzy; this was 2005/2006.) It could be that we knew the USRP didn't care about bigger blocks (since it's a stream of samples). Or that we never made a 3rd write call until the 1st one finished.
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