> I think this is the issue: > > I/O thread vCPU thread > ----------------------------------------------------------------------- > executes 1,000,000,000-th instruction > wakes up I/O thread > finds 1st timer > runs 1st timer > executes 1,000 instructions > ----------- QEMU_CLOCK_VIRTUAL now is 1,000,001,000 -------------------- > 1st timer finishes > executes 10,000 instructions > ----------- QEMU_CLOCK_VIRTUAL now is 1,000,011,000 -------------------- > runs 2nd timer
I would agree this is the issue. I was thinking that the timer ran in the same thread as the CPU (thus preventing the two from running at the same time) but I guess this is not true. There must be some sync point, because taking too long to finish the timer makes things stall (or that may just be due to causing a delay in delivery of the next interrupt.) So I guess what I am looking for is a way to ensure the two run mutually exclusive of each other. I know from other systems that we can run all this in a single thread (hardware models and guest CPU) so it should be possible to do in QEMU as well. Steven
