[LAD] [LAU] cancelling I/O with libsndfile

[Dan Muresan]

Hi Paul, thanks for replying.

> to. It seems as though you think there is a difference in the
> throughput when you read from a filesystem using st_blksize or some
> other size close to it, and that you either have or could measure it.

I was saying the man page provides the definitive guide to structuring
request sizes, and sndfile breaks the rules. The rules are there for
NFS, NTFS, EXT3, JFS, FTPS, SSHFS etc, PLUS future drivers.

> Erik is saying that he doesn't believe that you could measure the
> difference.

Well, who knows? To be future-proof one must follow standards.

> values very, very far removed from st_blksize. This is why ardour

st_blksize is only a common denominator. It is not a "preferred size".
I.e. if st_blksize is 1024, you could use 1k, 4k or 16k as a buffer
size -- just don't read() 1020 bytes, which sndfile does, all the
time, with impunity :)

Now, have you measured that reading exactly 10,000 bytes at a time was
optimal? That would be an argument against st_blksize being
meaningful.

> tries to write in chunks of 256kB, although in truth it would be

So you *do* pay attention to even block sizes in Ardour :)


-- Dan