----- Original Message ----- > From: "Pavel Dovgalyuk" <dovga...@ispras.ru> > To: "Paolo Bonzini" <pbonz...@redhat.com>, qemu-devel@nongnu.org > Cc: "serge fdrv" <serge.f...@gmail.com>, "pavel dovgaluk" > <pavel.dovga...@ispras.ru>, "peter maydell" > <peter.mayd...@linaro.org> > Sent: Thursday, February 2, 2017 11:07:12 PM > Subject: RE: [RFC/RFT PATCH 0/7] cpu-exec: simplify cpu_exec and remove some > icount special cases > > > From: Paolo Bonzini [mailto:paolo.bonz...@gmail.com] On Behalf Of Paolo > > Bonzini > > On 31/01/2017 01:05, Pavel Dovgalyuk wrote: > > > Hi, Paolo! > > > > > > Thanks for refactoring. > > > I tested these patches with icount record/replay on i386 machine. > > > It works, but the following changes should be applied. > > > I also removed call to replay_has_interrupt, because now it is not needed > > > here. > > > It seems, that this call is an artifact of an older record/replay > > > revision. > > > > > > diff --git a/cpu-exec.c b/cpu-exec.c > > > index 3838eb8..5cef8bc 100644 > > > --- a/cpu-exec.c > > > +++ b/cpu-exec.c > > > @@ -519,7 +519,8 @@ static inline bool cpu_handle_interrupt(CPUState > > > *cpu, > > > } > > > > > > /* Finally, check if we need to exit to the main loop. */ > > > - if (unlikely(atomic_read(&cpu->exit_request) || > > > replay_has_interrupt())) { > > > + if (unlikely(atomic_read(&cpu->exit_request) > > > + || (use_icount && cpu->icount_decr.u16.low + cpu->icount_extra > > > == 0))) { > > > atomic_set(&cpu->exit_request, 0); > > > cpu->exception_index = EXCP_INTERRUPT; > > > return true; > > > > So is this needed to avoid exceptions in tb_find? Please add a comment > > about this > > This code comes from my last patch, that was not applied. > Here is the comment: > > It adds check to break cpu loop when icount expires without > setting the TB_EXIT_ICOUNT_EXPIRED flag. It happens when there is no > available translated blocks and all instructions were executed. > In icount replay mode unnecessary tb_find will be called (which may > cause an exception) and execution will be non-deterministic. > > > and check if you can also replace: > > > > atomic_set(&cpu->exit_request, 1); > > > > in cpu_loop_exec_tb with > > > > cpu->icount_decr.u16.low = 0; > > > > ? > > > > This line is not needed at all, because the following code decrements > icount automatically. > > if (insns_left > 0) { > cpu_exec_nocache(cpu, insns_left, tb, false); > }
Right, so please send a patch and we can apply my series + yours. Paolo
