Date: Fri, 23 Aug 2013 16:21:29 +0800 From: Julian Elischer <julian@freebsd.org> To: Andre Oppermann <andre@freebsd.org> Cc: FreeBSD Net <net@FreeBSD.org> Subject: Re: TSO and FreeBSD vs Linux Message-ID: <52171B89.8030602@freebsd.org> In-Reply-To: <5214F506.3070706@freebsd.org> References: <520A6D07.5080106@freebsd.org> <5214F506.3070706@freebsd.org>
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On 8/22/13 1:12 AM, Andre Oppermann wrote: > On 13.08.2013 19:29, Julian Elischer wrote: >> I have been tracking down a performance embarrassment on AMAZON EC2 >> and have found it I think. >> Our OS cousins over at Linux land have implemented some interesting >> behaviour when TSO is in use. > > There used to be a different problem with EC2 and FreeBSD TSO. The > Xen hypervisor > doesn't like large 64K TSO bursts we generate, the drivers drops the > whole TSO chain, > TCP gets upset and turns off TSO alltogether leaving the connection > going at one > packet a time as in the old days. > > The problem is already fixed in recent EC2 9-stable images provided > by cperciva. > yes we have those fixes.
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