[rds-devel] So what is RDS congestion ?

Olaf Kirch olaf.kirch at oracle.com
Wed Nov 14 23:05:27 PST 2007


On Thursday 15 November 2007 03:46, Richard Frank wrote:
> A back pressured sender can either issue a blocking send and wait for 
> can wait in poll with pollin. When the recv socket is un-congested - due 
> to the process pulling off messages, a congestion update message is sent 
> to nodes with back pressured senders which results in waking poll 
> waiters with pollin.

Yuck! You wait for output using POLLIN?

I'm sorry, but that's just weird. I was close to ripping out the
piece of code that asserts POLLIN when a congestion map update
was received. I'd still like to rip this out, but at least I understand
the motivation of that code now.

With warts like this, RDS is never going to get merged into mainline

Olaf
-- 
Olaf Kirch  |  --- o --- Nous sommes du soleil we love when we play
okir at lst.de |    / | \   sol.dhoop.naytheet.ah kin.ir.samse.qurax



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