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
| ||
|
Date: Thu, 26 May 2011 09:28:16 -0600 From: Chris Friesen <chris.friesen@...band.com> To: Ben Greear <greearb@...delatech.com> CC: rick.jones2@...com, Stephen Hemminger <shemminger@...tta.com>, netdev <netdev@...r.kernel.org> Subject: Re: TCP funny-ness when over-driving a 1Gbps link (and wifi) On 05/20/2011 03:33 PM, Ben Greear wrote: > I tried a different test today: 3 TCP connections between two > wifi station interfaces (using ath9k). Each connection is > endpoint configured to send 100Mbps of traffic to the peer. > > With a single connection, it does OK (maybe 250ms round-trip time max). > With 3 of them running, round-trip user-space to user-space latency > often goes above 3 seconds. <snip> > So, seems a general issue with over-driving links with multiple TCP > connections. Doesn't seem like a regression, and probably not really > a bug, but maybe the buffer-bloat project will help this sort of > thing... Given that one rule of thumb for the send buffer size is twice the bandwidth delay product, it seems clear that on a wifi connection 3 seconds worth of buffering is excessive. I think I'd classify that as a bug. Chris -- Chris Friesen Software Developer GENBAND chris.friesen@...band.com www.genband.com -- 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
Powered by blists - more mailing lists