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Re: Spiped + Mysql over a LAN, high latency?

Thanks Colin for fixing this issue. I've run some tests with the last patch applied and spiped outperformed stunnel and ssh -L

ssh -L transmitted 540 queries/second
stunnel 600 queries/second.
spiped 800 queries/second

Mauro Ciancio

On Mon, Jan 26, 2015 at 6:24 AM, Colin Percival <cperciva@tarsnap.com> wrote:
Bringing this back to the list after some off-list tcpdumps...

On 01/21/15 04:28, Mauro Ciancio wrote:

> The problem I'm having is that spiped is adding latency (I guess so).

Turns out that this was caused by the interaction of nagling and TCP

delayed ACK.  I'm not sure why the Linux network stack wants to use

these bandwidth-saving techniques when communicating over the loopback

interface, but I'm sure someone had a very good reason.

I've set TCP_NODELAY to disable nagling; the potential bandwidth waste

due to TCP/IP overhead is minimal since spiped is sending 1060 bytes of

TCP/IP payload at a time over the encrypted connection (1024 bytes of

spiped payload + 4 byte payload length + 32 byte hmac).

Commit: https://code.google.com/p/spiped/source/detail?r=184

I'll release spiped 1.5.0 at some point with this included.  If anyone

else has anything which they want to see in 1.5.0, make sure you speak

up in the next few weeks.


Colin Percival

Security Officer Emeritus, FreeBSD | The power to serve

Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid