Re: [Qemu-devel] [RFC PATCH 01/12] icount: put icount variables into TimerState.

[Paolo Bonzini <pbonzini@redhat.com>]

Il 21/03/2014 20:17, fred.konrad@greensocs.com ha scritto:
> From: KONRAD Frederic <fred.konrad@greensocs.com>
>
> This puts qemu_icount and qemu_icount_bias into TimerState structure to allow
> them to be migrated.
>
> Signed-off-by: KONRAD Frederic <fred.konrad@greensocs.com>
> ---
>  cpus.c | 29 ++++++++++++++++-------------
>  1 file changed, 16 insertions(+), 13 deletions(-)
>
> diff --git a/cpus.c b/cpus.c
> index 1104d61..687717f 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -100,17 +100,12 @@ static bool all_cpu_threads_idle(void)
>
>  /* Protected by TimersState seqlock */
>
> -/* Compensate for varying guest execution speed.  */
> -static int64_t qemu_icount_bias;
>  static int64_t vm_clock_warp_start;
>  /* Conversion factor from emulated instructions to virtual clock ticks.  */
>  static int icount_time_shift;
>  /* Arbitrarily pick 1MIPS as the minimum allowable speed.  */
>  #define MAX_ICOUNT_SHIFT 10
>
> -/* Only written by TCG thread */
> -static int64_t qemu_icount;
> -
>  static QEMUTimer *icount_rt_timer;
>  static QEMUTimer *icount_vm_timer;
>  static QEMUTimer *icount_warp_timer;
> @@ -127,6 +122,11 @@ typedef struct TimersState {
>      int64_t cpu_clock_offset;
>      int32_t cpu_ticks_enabled;
>      int64_t dummy;
> +
> +    /* Compensate for varying guest execution speed.  */
> +    int64_t qemu_icount_bias;
> +    /* Only written by TCG thread */
> +    int64_t qemu_icount;
>  } TimersState;
>
>  static TimersState timers_state;
> @@ -137,14 +137,14 @@ static int64_t cpu_get_icount_locked(void)
>      int64_t icount;
>      CPUState *cpu = current_cpu;
>
> -    icount = qemu_icount;
> +    icount = timers_state.qemu_icount;
>      if (cpu) {
>          if (!cpu_can_do_io(cpu)) {
>              fprintf(stderr, "Bad clock read\n");
>          }
>          icount -= (cpu->icount_decr.u16.low + cpu->icount_extra);
>      }
> -    return qemu_icount_bias + (icount << icount_time_shift);
> +    return timers_state.qemu_icount_bias + (icount << icount_time_shift);
>  }
>
>  int64_t cpu_get_icount(void)
> @@ -282,7 +282,8 @@ static void icount_adjust(void)
>          icount_time_shift++;
>      }
>      last_delta = delta;
> -    qemu_icount_bias = cur_icount - (qemu_icount << icount_time_shift);
> +    timers_state.qemu_icount_bias = cur_icount
> +                              - (timers_state.qemu_icount << icount_time_shift);
>      seqlock_write_unlock(&timers_state.vm_clock_seqlock);
>  }
>
> @@ -331,7 +332,7 @@ static void icount_warp_rt(void *opaque)
>              int64_t delta = cur_time - cur_icount;
>              warp_delta = MIN(warp_delta, delta);
>          }
> -        qemu_icount_bias += warp_delta;
> +        timers_state.qemu_icount_bias += warp_delta;
>      }
>      vm_clock_warp_start = -1;
>      seqlock_write_unlock(&timers_state.vm_clock_seqlock);
> @@ -349,7 +350,7 @@ void qtest_clock_warp(int64_t dest)
>          int64_t deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
>          int64_t warp = MIN(dest - clock, deadline);
>          seqlock_write_lock(&timers_state.vm_clock_seqlock);
> -        qemu_icount_bias += warp;
> +        timers_state.qemu_icount_bias += warp;
>          seqlock_write_unlock(&timers_state.vm_clock_seqlock);
>
>          qemu_clock_run_timers(QEMU_CLOCK_VIRTUAL);
> @@ -1248,7 +1249,8 @@ static int tcg_cpu_exec(CPUArchState *env)
>          int64_t count;
>          int64_t deadline;
>          int decr;
> -        qemu_icount -= (cpu->icount_decr.u16.low + cpu->icount_extra);
> +        timers_state.qemu_icount -= (cpu->icount_decr.u16.low
> +                                    + cpu->icount_extra);
>          cpu->icount_decr.u16.low = 0;
>          cpu->icount_extra = 0;
>          deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
> @@ -1263,7 +1265,7 @@ static int tcg_cpu_exec(CPUArchState *env)
>          }
>
>          count = qemu_icount_round(deadline);
> -        qemu_icount += count;
> +        timers_state.qemu_icount += count;
>          decr = (count > 0xffff) ? 0xffff : count;
>          count -= decr;
>          cpu->icount_decr.u16.low = decr;
> @@ -1276,7 +1278,8 @@ static int tcg_cpu_exec(CPUArchState *env)
>      if (use_icount) {
>          /* Fold pending instructions back into the
>             instruction counter, and clear the interrupt flag.  */
> -        qemu_icount -= (cpu->icount_decr.u16.low + cpu->icount_extra);
> +        timers_state.qemu_icount -= (cpu->icount_decr.u16.low
> +                        + cpu->icount_extra);
>          cpu->icount_decr.u32 = 0;
>          cpu->icount_extra = 0;
>      }
>

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>