On 23 June 2015 at 19:15, Peter Maydell <peter.mayd...@linaro.org> wrote: > On 23 June 2015 at 08:31, Frederic Konrad <fred.kon...@greensocs.com> wrote: >> The normal boot with "-smp 4" and a smp 4 guest is slow and become a lot >> faster >> when I enable the window (which have timer callbacks and refresh the screen >> regularly) > > Is it just overall slow, or does it appear to hang? I have an > interesting effect where *with* this patch an -smp 3 or 4 guest > boot seems to hang between "SCSI subsystem initialized" and > "Switched to clocksource arch_sys_counter"...
At least part of what is happening here seems to be that we're falling into a similar flavour of stall to the original test case: in the SMP 3 setup, CPU #2 is in the busy-loop of Linux's multi_cpu_stop() function, and it can sit in that loop for an entire second. We should never let a single CPU grab execution for that long when doing TCG round-robin... -- PMM
