Date: Sat, 06 Sep 2014 00:43:29 +0200 From: Hans Petter Selasky <hps@selasky.org> To: Rick Macklem <rmacklem@uoguelph.ca> Cc: freebsd-net@freebsd.org, Eric Joyner <ricera10@gmail.com>, FreeBSD Current <freebsd-current@freebsd.org>, Scott Long <scottl@freebsd.org>, Jack F Vogel <jfvogel@gmail.com> Subject: Re: [RFC] Patch to improve TSO limitation formula in general Message-ID: <540A3C91.406@selasky.org> In-Reply-To: <1762951742.33012989.1409954952800.JavaMail.root@uoguelph.ca> References: <1762951742.33012989.1409954952800.JavaMail.root@uoguelph.ca>
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On 09/06/14 00:09, Rick Macklem wrote: > Hans Petter Selesky wrote: >> On 09/05/14 23:19, Eric Joyner wrote: >>> There are some concerns if we use this with devices that ixl >>> supports: >>> >>> - The maximum fragment size is 16KB-1, which isn't a power of 2. >>> >> >> Hi Eric, >> >> Multiplying by powers of two are more fast, than non-powers of two. >> So >> in this case you would have to use 8KB as a maximum. >> > Well, I'm no architecture expert, but I really doubt the CPU delay of a > non-power of 2 multiply/divide is significant related to doing smaller > TSO segments. Long ago (as in 1970s) I did work on machines where shifts > for power of 2 multiply/divide was preferable, but these days I doubt it > is going to matter?? > Hi, You also need to patch LAGG and VLAN drivers? --HPS
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