svn commit: r277213 - in head: share/man/man9 sys/kern sys/ofed/include/linux sys/sys

[Konstantin Belousov]

On Tue, Jan 20, 2015 at 05:30:25AM +0100, Hans Petter Selasky wrote:
> On 01/19/15 22:59, Adrian Chadd wrote:
> > Hi,
> >
> > Would you please check what the results of this are with CPU specific
> > callwheels?
> >
> > I'm doing some 10+ gig traffic testing on -HEAD with RSS enabled (on
> > ixgbe) and with this setup, the per-CPU TCP callwheel stuff is
> > enabled. But all the callwheels are now back on clock(0) and so is the
> > lock contention. :(
> >
> > Thanks,
> >
> 
> Hi,
> 
> Like stated in the manual page, callout_reset_curcpu/on() does not work 
> with MPSAFE callouts any more!
I.e. you 'fixed' some undeterminate bugs in callout migration by not
doing migration at all anymore.

> 
> You need to use callout_init_{mtx,rm,rw} and remove the custom locking 
> inside the callback in the TCP stack to get it working like before!

No, you need to do this, if you think that whole callout KPI must be
rototiled.  It is up to the person who modifies the KPI, to ensure that
existing code is not broken.

As I understand, currently we are back to the one-cpu callouts.
Do other people consider this situation acceptable ?