[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH] icount: remove useless exit_request assignment
From: |
Paolo Bonzini |
Subject: |
Re: [Qemu-devel] [PATCH] icount: remove useless exit_request assignment |
Date: |
Tue, 7 Feb 2017 16:28:15 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.5.1 |
On 07/02/2017 07:54, Pavel Dovgalyuk wrote:
> This patch removes unneeded assignment to cpu->exit_request.
> cpu_exec_nocache executes all available instructions and therefore
> icount becomes 0. Then other conditions will break the execution
> loop, making assignment to cpu->exit_request useless.
>
> This patch should be applied over Paolo's series:
> https://www.mail-archive.com/address@hidden/msg426058.html
>
> Signed-off-by: Pavel Dovgalyuk <address@hidden>
> ---
> cpu-exec.c | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/cpu-exec.c b/cpu-exec.c
> index 5cef8bc..91d1faf 100644
> --- a/cpu-exec.c
> +++ b/cpu-exec.c
> @@ -577,7 +577,6 @@ static inline void cpu_loop_exec_tb(CPUState *cpu,
> TranslationBlock *tb,
> if (insns_left > 0) {
> cpu_exec_nocache(cpu, insns_left, tb, false);
> }
> - atomic_set(&cpu->exit_request, 1);
> }
> }
>
>
Nice, thanks. We can just squash the two patches with my 7/7 like this:
diff --git a/cpu-exec.c b/cpu-exec.c
index 9a7ff1b..1026cd0 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -517,7 +517,10 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
*last_tb = NULL;
}
}
- if (unlikely(atomic_read(&cpu->exit_request) || replay_has_interrupt())) {
+
+ /* Finally, check if we need to exit to the main loop. */
+ 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;
@@ -527,8 +530,7 @@ static inline bool cpu_handle_interrupt(CPUState *cpu,
}
static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb,
- TranslationBlock **last_tb, int *tb_exit,
- SyncClocks *sc)
+ TranslationBlock **last_tb, int *tb_exit)
{
uintptr_t ret;
int32_t insns_left;
@@ -578,10 +580,7 @@ static inline void cpu_loop_exec_tb(CPUState *cpu,
TranslationBlock *tb,
*/
if (insns_left > 0) {
cpu_exec_nocache(cpu, insns_left, tb, false);
- align_clocks(sc, cpu);
}
- cpu->exception_index = EXCP_INTERRUPT;
- cpu_loop_exit(cpu);
}
}
@@ -641,7 +640,7 @@ int cpu_exec(CPUState *cpu)
while (!cpu_handle_interrupt(cpu, &last_tb)) {
TranslationBlock *tb = tb_find(cpu, last_tb, tb_exit);
- cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit, &sc);
+ cpu_loop_exec_tb(cpu, tb, &last_tb, &tb_exit);
/* Try to align the host and virtual clocks
if the guest is in advance */
align_clocks(&sc, cpu);