Message ID | 20191205223008.8623-1-andrew.cooper3@citrix.com (mailing list archive) |
---|---|
Headers | show |
Series | xen: Support continuations from tasklets | expand |
On 05.12.2019 23:30, Andrew Cooper wrote: > From testing this series, I have re-confirmed the previous reported > observation that: > > # while :; do xen-hptool smt-enable; xen-hptool smt-disable; done > > in dom0 eventually causes the serial console to cease working (wedge midway > through printing a line). > > There are sporadic "Broke affinity for IRQ26, new: ffff" messages, but the > serial always seems to break shortly after the first "Broke affinity for > IRQ30, new: ffff". Both IRQs are non-descript PCI-MSI/-X interrupts bound to > dom0. And neither IRQ30 not IRQ26 are the serial ones? And serial does use an IRQ (i.e. isn't running in polling mode)? I'll see if I can repro (and then maybe be able to debug). Jan
On 06/12/2019 09:58, Jan Beulich wrote: > On 05.12.2019 23:30, Andrew Cooper wrote: >> From testing this series, I have re-confirmed the previous reported >> observation that: >> >> # while :; do xen-hptool smt-enable; xen-hptool smt-disable; done >> >> in dom0 eventually causes the serial console to cease working (wedge midway >> through printing a line). >> >> There are sporadic "Broke affinity for IRQ26, new: ffff" messages, but the >> serial always seems to break shortly after the first "Broke affinity for >> IRQ30, new: ffff". Both IRQs are non-descript PCI-MSI/-X interrupts bound to >> dom0. > And neither IRQ30 not IRQ26 are the serial ones? And serial does > use an IRQ (i.e. isn't running in polling mode)? I'll see if I > can repro (and then maybe be able to debug). Serial uses IRQ0 and never has affinity changes as it is always bound to CPU0. Given our recent fun with the PEOI stack, that was going to be my next port of call. However everything else in the system looks to be working fine, including the disks and network, suggesting that we aren't losing other interrupts. ~Andrew
On 06.12.2019 11:14, Andrew Cooper wrote: > On 06/12/2019 09:58, Jan Beulich wrote: >> On 05.12.2019 23:30, Andrew Cooper wrote: >>> From testing this series, I have re-confirmed the previous reported >>> observation that: >>> >>> # while :; do xen-hptool smt-enable; xen-hptool smt-disable; done >>> >>> in dom0 eventually causes the serial console to cease working (wedge midway >>> through printing a line). >>> >>> There are sporadic "Broke affinity for IRQ26, new: ffff" messages, but the >>> serial always seems to break shortly after the first "Broke affinity for >>> IRQ30, new: ffff". Both IRQs are non-descript PCI-MSI/-X interrupts bound to >>> dom0. >> And neither IRQ30 not IRQ26 are the serial ones? And serial does >> use an IRQ (i.e. isn't running in polling mode)? I'll see if I >> can repro (and then maybe be able to debug). > > Serial uses IRQ0 and never has affinity changes as it is always bound to > CPU0. IRQ0? DYM IRQ3 or IRQ4? (In any event the important part is for it to be in the ISA range, rather than the PCI one.) > Given our recent fun with the PEOI stack, that was going to be my next > port of call. However everything else in the system looks to be working > fine, including the disks and network, suggesting that we aren't losing > other interrupts. The high priority vector we use for serial makes the PEOI stack unrelated afaict, as mentioned in the discussion there as well. Jan
On 06/12/2019 10:18, Jan Beulich wrote: > On 06.12.2019 11:14, Andrew Cooper wrote: >> On 06/12/2019 09:58, Jan Beulich wrote: >>> On 05.12.2019 23:30, Andrew Cooper wrote: >>>> From testing this series, I have re-confirmed the previous reported >>>> observation that: >>>> >>>> # while :; do xen-hptool smt-enable; xen-hptool smt-disable; done >>>> >>>> in dom0 eventually causes the serial console to cease working (wedge midway >>>> through printing a line). >>>> >>>> There are sporadic "Broke affinity for IRQ26, new: ffff" messages, but the >>>> serial always seems to break shortly after the first "Broke affinity for >>>> IRQ30, new: ffff". Both IRQs are non-descript PCI-MSI/-X interrupts bound to >>>> dom0. >>> And neither IRQ30 not IRQ26 are the serial ones? And serial does >>> use an IRQ (i.e. isn't running in polling mode)? I'll see if I >>> can repro (and then maybe be able to debug). >> Serial uses IRQ0 and never has affinity changes as it is always bound to >> CPU0. > IRQ0? DYM IRQ3 or IRQ4? (In any event the important part is for it > to be in the ISA range, rather than the PCI one.) I do mean IRQ4, sorry. Mixed it up with the timer IRQ. On SMT disable, it does lose half of its affinity. (XEN) IRQ: 4 vec:f1 IO-APIC-edge status=000 aff:{0-7}/{0,2,4,6} drivers/char/ns16550.c#ns16550_interrupt() So this is more likely to be related to a irq-migration than LAPIC acks. ~Andrew