On 27 August 2014 13:17, David Gwynne <da...@gwynne.id.au> wrote: > On Tue, Aug 26, 2014 at 09:11:14PM -0400, Brad Smith wrote: >> On 20/08/14 8:03 PM, David Gwynne wrote: >> >sthen@ says this is likely a bit optimistic. while most of our drivers >> >unconditionally configure their max mru, there's some stupid ones that >> >still interpret the configured mtu as a what the mru should be. >> > >> >dlg >> >> oce(4) and ix(4) need to be fixed. > > this might fix ix(4). anyone able to test? >
ix and oce (internally though) calculate various paramethers related to flow control, internal buffer sizes and so on based on the maximum frame size. therefore if i set max frame size to 16k but always use 1,5k all these calculations will be off. and by killing SIOCSIFMTU you make it impossible for the driver to readjust them. we have no idea at the moment how will this affect nic's behavior. pieces of such black magic such as the code under /* Hardware Packet Buffer & Flow Control setup */ comment must be studied before making such changes. and as i've mentioned to dlg, ix diff also switches it to using 16k cluster pool no matter what you actually need. this can be changed, but needs testing (i'm doing it now).
