netdev - Very low latency TCP for clusters

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <AANLkTilNmNZbFWS8LF-UHU65QYIC32HZlgVZ7lXJHxPh@mail.gmail.com>
Date:	Mon, 19 Jul 2010 10:05:19 -0700
From:	Tom Herbert <therbert@...gle.com>
To:	netdev@...r.kernel.org
Subject: Very low latency TCP for clusters

We have been looking at best case TCP latencies that might be achieved
within a cluster (low loss fabric).  The goal is to have latency
numbers roughly comparable to that which can be produced using RDMA/IB
in a low latency configuration  (<5 usecs round trip on netperf TCP_RR
test with one byte data for directly connected hosts as a starting
point).  This would be without changing sockets API, fabric, and
preferably not using TCP offload or a user space stack.

I think there are at least two techniques that will drive down TCP
latency: per connection queues and polling queues.  Per connection
queues (supported by device) should eliminate costs of connection
look-up, hopefully some locking.  Polling becomes viable as core
counts on systems increase, and burning a few CPUs for networking
polling on behalf of very low-latency threads would be reasonable.

Are there any efforts in progress to integrate per connection queues
in the stack or integrate polling of queues?

Thanks,
Tom
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html