[rds-devel] RDS IB transport software flow control?
Olaf Kirch
olaf.kirch at oracle.com
Wed Nov 7 05:17:17 PST 2007
On Wednesday 07 November 2007 13:18, Richard Frank wrote:
> Who sets - max recv memory ?
It's a sysctl, and it defaults to one third of all available RAM,
which is pretty generous IMO :)
> Part of the reasoning for so_rcvbuf - is that this is an existing
> application tuning knob - which for example, one app I'm familiar with
> uses today.
Yes, and it can continue to do so.
> Senders can only send so_sndbuf - worth of sends - without getting back
> "credits" via the RC ACK. So the recving side has the opportunity to
> send back the congestion message (NAK) along with / or before the ACK.
>
> This somewhat bounds the recv memory to sender so_sndbuf * number of
> senders to a destination - which is probably not that limiting...
That was my point, indeed.
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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