On Sat, Jan 25, 2020 at 02:41:39PM -0500, Waiman Long wrote: > On 1/24/20 11:58 PM, Paul E. McKenney wrote: > > On Fri, Jan 24, 2020 at 09:17:05PM -0500, Waiman Long wrote: > >> On 1/24/20 8:59 PM, Waiman Long wrote: > >>>> You called it! I will play with QEMU's -numa argument to see if I can get > >>>> CNA to run for me. Please accept my apologies for the false alarm. > >>>> > >>>> Thanx, Paul > >>>> > >>> CNA is not currently supported in a VM guest simply because the numa > >>> information is not reliable. You will have to run it on baremetal to > >>> test it. Sorry for that. > >> Correction. There is a command line option to force CNA lock to be used > >> in a VM. Use the "numa_spinlock=on" boot command line parameter. > > As I understand it, I need to use a series of -numa arguments to qemu > > combined with the numa_spinlock=on (or =1) on the kernel command line. > > If the kernel thinks that there is only one NUMA node, it appears to > > avoid doing CNA. > > > > Correct? > > > > Thanx, Paul > > > In auto-detection mode (the default), CNA will only be turned on when > paravirt qspinlock is not enabled first and there are at least 2 numa > nodes. The "numa_spinlock=on" option will force it on even when both of > the above conditions are false. Hmmm... Here is my kernel command line taken from the console log: console=ttyS0 locktorture.onoff_interval=0 numa_spinlock=on locktorture.stat_interval=15 locktorture.shutdown_secs=1800 locktorture.verbose=1 Yet the string "Enabling CNA spinlock" does not appear. Ah, idiot here needs to enable CONFIG_NUMA_AWARE_SPINLOCKS in his build. Trying again with "--kconfig "CONFIG_NUMA_AWARE_SPINLOCKS=y"... Thanx, Paul
