Hi, I was trying to set irq affinity by writing a value to /proc/irq/<irq>/smp_affinity, but smp_affinity value was not changed at all. Ian suggested to take this to the devel list. I'm working on Xen4.5, ARMv8.
Thanks, Jintack On Thu, Sep 3, 2015 at 11:34 AM, Ian Campbell <ian.campb...@citrix.com> wrote: > On Thu, 2015-09-03 at 10:59 -0400, Jintack Lim wrote: > > Hi, > > > > While I was running Apache server, > > I found that one of Dom0 vcpu is running 100% to handle irqs, > > and those irqs are set to be processed only on that specific vcpu. > > > > Referring to this document, > > http://wiki.xen.org/wiki/Network_Throughput_and_Performance_Guide > > I tried to change smp_affinity by writing a value to /proc/irq/<irq > > -no>/smp_affinity, > > however the smp_affinity value was not changed. > > > > I'm working on Xen 4.5 on ARMv8, > > and the irq is netback tx interrupt. > > > > # cat /proc/irq/106/smp_affinity > > 1 > > > > # cat /proc/interrupts > > ... > > 106: 53849 0 0 0 xen-dyn-event > > vif1.1-q0-tx > > 107: 1 0 0 0 xen-dyn-event > > vif1.1-q0-rx > > 108: 61460 0 0 0 xen-dyn-event > > vif1.1-q1-tx > > 109: 1 0 0 0 xen-dyn-event > > vif1.1-q1-rx > > 110: 67118 0 0 0 xen-dyn-event > > vif1.1-q2-tx > > 111: 1 0 0 0 xen-dyn-event > > vif1.1-q2-rx > > 112: 58273 0 0 0 xen-dyn-event > > vif1.1-q3-tx > > 113: 1 0 0 0 xen-dyn-event > > vif1.1-q3-rx > > ... > > > > What would be the way to change smp_affinity? > > It should be via /proc/irq/<irq>/smp_affinity as you've tried, I asked > Stefano and he things this was already implemented in 4.5 even. That it is > not happening would be a bug, I think. > > I'd suggest you take this to the devel list as a bug. > > > and where is the affinity set initially for netback tx interrupts? > > Not, sure, I think it might just be generic IRQ code. > > Ian. > >
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