[Bloat] using tcp_notsent_lowat in various apps?

[Jonathan Morton]

> On 16 Jun, 2015, at 19:18, Steinar H. Gunderson <sgunderson at bigfoot.com> wrote:
> 
> On Tue, Jun 16, 2015 at 09:11:08AM -0700, Dave Taht wrote:
>> I just tossed off a quick patch for rsync, not that I have a clue as
>> to whether it would make any difference there.
> 
> For bulk applications (like rsync), how would this make sense at all?
> I thought the entire point of this option was if you knew what data to send
> now, but that you might want to change your mind later if it takes some time
> to send it. The latter doesn't apply to rsync.

Actually, it does.  Rsync is designed to be used to update an existing set of files, so the protocol interleaves control and data information asynchronously.

More generally, I think it’s worth setting LOWAT on *any* application that uses select() or poll() with a readable and writable socket population simultaneously.

- Jonathan Morton