On 03/06/16 23:40, Alex Bennée wrote:
> In preparation for multi-threaded TCG we remove tcg_exec_all and move
> all the CPU cycling into the main thread function. When MTTCG is enabled
> we shall use a separate thread function which only handles one vCPU.
>
> Signed-off-by: Alex Bennée <alex.ben...@linaro.org>
Reviewed-by: Sergey Fedorov <sergey.fedo...@linaro.org>
>
> ---
> v2
> - update timer calls to new API on rebase
> v3
> - move tcg_cpu_exec above thread function, drop static fwd declaration
> ---
> cpus.c | 185
> +++++++++++++++++++++++++++++++----------------------------------
> 1 file changed, 89 insertions(+), 96 deletions(-)
>
> diff --git a/cpus.c b/cpus.c
> index c404dd7..4cc2ce6 100644
> --- a/cpus.c
> +++ b/cpus.c
> @@ -69,7 +69,6 @@
>
> #endif /* CONFIG_LINUX */
>
> -static CPUState *next_cpu;
> int64_t max_delay;
> int64_t max_advance;
>
> @@ -1119,7 +1118,67 @@ static void *qemu_dummy_cpu_thread_fn(void *arg)
> #endif
> }
>
> -static void tcg_exec_all(void);
> +static int64_t tcg_get_icount_limit(void)
> +{
> + int64_t deadline;
> +
> + if (replay_mode != REPLAY_MODE_PLAY) {
> + deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
> +
> + /* Maintain prior (possibly buggy) behaviour where if no deadline
> + * was set (as there is no QEMU_CLOCK_VIRTUAL timer) or it is more
> than
> + * INT32_MAX nanoseconds ahead, we still use INT32_MAX
> + * nanoseconds.
> + */
> + if ((deadline < 0) || (deadline > INT32_MAX)) {
> + deadline = INT32_MAX;
> + }
> +
> + return qemu_icount_round(deadline);
> + } else {
> + return replay_get_instructions();
> + }
> +}
> +
> +static int tcg_cpu_exec(CPUState *cpu)
> +{
> + int ret;
> +#ifdef CONFIG_PROFILER
> + int64_t ti;
> +#endif
> +
> +#ifdef CONFIG_PROFILER
> + ti = profile_getclock();
> +#endif
> + if (use_icount) {
> + int64_t count;
> + int decr;
> + timers_state.qemu_icount -= (cpu->icount_decr.u16.low
> + + cpu->icount_extra);
> + cpu->icount_decr.u16.low = 0;
> + cpu->icount_extra = 0;
> + count = tcg_get_icount_limit();
> + timers_state.qemu_icount += count;
> + decr = (count > 0xffff) ? 0xffff : count;
> + count -= decr;
> + cpu->icount_decr.u16.low = decr;
> + cpu->icount_extra = count;
> + }
> + ret = cpu_exec(cpu);
> +#ifdef CONFIG_PROFILER
> + tcg_time += profile_getclock() - ti;
> +#endif
> + if (use_icount) {
> + /* Fold pending instructions back into the
> + instruction counter, and clear the interrupt flag. */
> + timers_state.qemu_icount -= (cpu->icount_decr.u16.low
> + + cpu->icount_extra);
> + cpu->icount_decr.u32 = 0;
> + cpu->icount_extra = 0;
> + replay_account_executed_instructions();
> + }
> + return ret;
> +}
>
> static void *qemu_tcg_cpu_thread_fn(void *arg)
> {
> @@ -1150,8 +1209,35 @@ static void *qemu_tcg_cpu_thread_fn(void *arg)
> /* process any pending work */
> atomic_mb_set(&exit_request, 1);
>
> + cpu = first_cpu;
> +
> while (1) {
> - tcg_exec_all();
> + /* Account partial waits to QEMU_CLOCK_VIRTUAL. */
> + qemu_account_warp_timer();
> +
> + if (!cpu) {
> + cpu = first_cpu;
> + }
> +
> + for (; cpu != NULL && !exit_request; cpu = CPU_NEXT(cpu)) {
> +
> + qemu_clock_enable(QEMU_CLOCK_VIRTUAL,
> + (cpu->singlestep_enabled & SSTEP_NOTIMER) ==
> 0);
> +
> + if (cpu_can_run(cpu)) {
> + int r = tcg_cpu_exec(cpu);
> + if (r == EXCP_DEBUG) {
> + cpu_handle_guest_debug(cpu);
> + break;
> + }
> + } else if (cpu->stop || cpu->stopped) {
> + break;
> + }
> +
> + } /* for cpu.. */
> +
> + /* Pairs with smp_wmb in qemu_cpu_kick. */
> + atomic_mb_set(&exit_request, 0);
>
> if (use_icount) {
> int64_t deadline =
> qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
> @@ -1448,99 +1534,6 @@ int vm_stop_force_state(RunState state)
> }
> }
>
> -static int64_t tcg_get_icount_limit(void)
> -{
> - int64_t deadline;
> -
> - if (replay_mode != REPLAY_MODE_PLAY) {
> - deadline = qemu_clock_deadline_ns_all(QEMU_CLOCK_VIRTUAL);
> -
> - /* Maintain prior (possibly buggy) behaviour where if no deadline
> - * was set (as there is no QEMU_CLOCK_VIRTUAL timer) or it is more
> than
> - * INT32_MAX nanoseconds ahead, we still use INT32_MAX
> - * nanoseconds.
> - */
> - if ((deadline < 0) || (deadline > INT32_MAX)) {
> - deadline = INT32_MAX;
> - }
> -
> - return qemu_icount_round(deadline);
> - } else {
> - return replay_get_instructions();
> - }
> -}
> -
> -static int tcg_cpu_exec(CPUState *cpu)
> -{
> - int ret;
> -#ifdef CONFIG_PROFILER
> - int64_t ti;
> -#endif
> -
> -#ifdef CONFIG_PROFILER
> - ti = profile_getclock();
> -#endif
> - if (use_icount) {
> - int64_t count;
> - int decr;
> - timers_state.qemu_icount -= (cpu->icount_decr.u16.low
> - + cpu->icount_extra);
> - cpu->icount_decr.u16.low = 0;
> - cpu->icount_extra = 0;
> - count = tcg_get_icount_limit();
> - timers_state.qemu_icount += count;
> - decr = (count > 0xffff) ? 0xffff : count;
> - count -= decr;
> - cpu->icount_decr.u16.low = decr;
> - cpu->icount_extra = count;
> - }
> - ret = cpu_exec(cpu);
> -#ifdef CONFIG_PROFILER
> - tcg_time += profile_getclock() - ti;
> -#endif
> - if (use_icount) {
> - /* Fold pending instructions back into the
> - instruction counter, and clear the interrupt flag. */
> - timers_state.qemu_icount -= (cpu->icount_decr.u16.low
> - + cpu->icount_extra);
> - cpu->icount_decr.u32 = 0;
> - cpu->icount_extra = 0;
> - replay_account_executed_instructions();
> - }
> - return ret;
> -}
> -
> -static void tcg_exec_all(void)
> -{
> - int r;
> -
> - /* Account partial waits to QEMU_CLOCK_VIRTUAL. */
> - qemu_account_warp_timer();
> -
> - if (next_cpu == NULL) {
> - next_cpu = first_cpu;
> - }
> - for (; next_cpu != NULL && !exit_request; next_cpu = CPU_NEXT(next_cpu))
> {
> - CPUState *cpu = next_cpu;
> -
> - qemu_clock_enable(QEMU_CLOCK_VIRTUAL,
> - (cpu->singlestep_enabled & SSTEP_NOTIMER) == 0);
> -
> - if (cpu_can_run(cpu)) {
> - r = tcg_cpu_exec(cpu);
> - if (r == EXCP_DEBUG) {
> - cpu_handle_guest_debug(cpu);
> - break;
> - }
> - } else if (cpu->stop || cpu->stopped) {
> - break;
> - }
> - }
> -
> - /* Pairs with smp_wmb in qemu_cpu_kick. */
> - atomic_mb_set(&exit_request, 0);
> -}
> -
> void list_cpus(FILE *f, fprintf_function cpu_fprintf, const char *optarg)
> {
> /* XXX: implement xxx_cpu_list for targets that still miss it */
