only happen on every Nth call. Update the existing twiddle() calls done in
various IO loops to roughly reflect the relative IO sizes. That is, tftp
and nfs call twiddle() on every 1K block, ufs on every filesystem block,
so the network calls now use a much larger divisor than disk IO calls.
Also add a new twiddle_divisor() function that allows an application to set
a global divisor that is applied on top of the per-call divisors. Nothing
calls this yet, but loader(8) will be using it to further throttle the
cursor for slow serial consoles.
- bzipfs and gzipfs now properly return errno values directly from their
read routines rather than returning -1.
- missing errno values on error returns for the seek routines on almost
all filesystems were added.
- fstat() now returns -1 if an error occurs rather than ignoring it.
- nfs's readdir() routine now reports valid errno values if an error or
EOF occurs rather than EPERM (It was just returning 0 for success and
1 for failure).
- nullfs used the wrong semantics for every function besides close() and
seek(). Getting it right for close() appears to be an accident at that.
- read() for buffered files no longer returns 0 (EOF) if an error occurs,
but returns -1 instead.
the efficiency of byte-by-byte read operations on filesystems not already
supported by the block cache (especially NFS).
This should be a welcome change for users booting via PXE, as the loader
now reads its startup files almost instantly, instead of taking tens of
seconds.
