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Re: [Discuss-gnuradio] fusb_nblock and fusb_block_size
From: |
Greg Troxel |
Subject: |
Re: [Discuss-gnuradio] fusb_nblock and fusb_block_size |
Date: |
Thu, 30 Nov 2006 13:29:16 -0500 |
User-agent: |
Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (berkeley-unix) |
fusb_block_size is the size in bytes of the maximum transfer that we
will ask the kernel to make to/from user-space. fusb_nblocks is the
maximum number of transfers (of maximum size fusb_block_size) that we
can have in flight at any given time.
I think this is Linux-specific. The NetSBD USB implementation takes
the numbers and pushes them into the kernel where I think there is
similar treatment (total size of read-ahead buffer, and size of IO
request made to USB subsystem).
We'll need to come up with a clean OS/HW independent way of dealing
with block sizes and controlling latency, along with enabling code to
end up at the lowest latency mode that works without hand tuning.