On Thu, 2019-04-04 at 14:56 -0700, Vinicius Costa Gomes wrote: > We have seen some reports[1] of users complaining that they aren't > able to use some queues when their machines have less than 4 cpus. > This affects some TSN workloads, as different traffic classes are > assigned different queues. The current behavior limits the number of > traffic classes that can be reliably handled. > > In practice, what is not working, it returns an invalid parameter > error, in hosts with less than 4 cpus is something like this: > > $ tc qdisc replace dev IFACE parent root mqprio \ > num_tc 3 map 2 2 1 0 2 2 2 2 2 2 2 2 2 2 2 2 \ > queues 1@0 1@1 2@2 hw 0 > > Because changing the default logic of the allocation of queues could > bring other effects, we propose adding a module parameter so expert > users may override that decision. > > [1] https://github.com/jeez/iproute2/issues/1 > > Reported-by: Bhagath Singh Karunakaran <bhag...@kalycito.com> > Signed-off-by: Vinicius Costa Gomes <vinicius.go...@intel.com> > --- > > A similar fix should also be needed for igc, even if I don't have the > hardware to test, I can produce a patch, if others are able to test. > > I am not totally sure that using a module parameter is the best > solution, so, suggestions are welcome. > > drivers/net/ethernet/intel/igb/igb_main.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-)
A module parameter maybe fine for our out-of-tree driver, but not for the kernel driver. NACK on the basis that a new module parameter is being introduced for the driver. This is not acceptable by Dave Miller or myself. As of now, I do not have a alternative solution to propose unfortunately. I will discuss the issue with my fellow developers and hopefully we can come up with a kernel interface that all drivers can use to handle this issue.
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