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[Qemu-devel] [PATCH v1 3/3] tcg-runtime: short-circuit lookup_tb_ptr on
From: |
Alex Bennée |
Subject: |
[Qemu-devel] [PATCH v1 3/3] tcg-runtime: short-circuit lookup_tb_ptr on IRQs |
Date: |
Wed, 14 Jun 2017 15:02:09 +0100 |
While the next TB would detect the exit flag has been set there is no
point if we can exit sooner. We also check cpu->interrupt_request as
some front-ends can set it rather than using the cpu_interrupt() API
call and would normally be expecting the IRQ to get picked up on the
previously fairly regular exits from the run loop.
Signed-off-by: Alex Bennée <address@hidden>
---
tcg-runtime.c | 47 +++++++++++++++++++++++++++--------------------
1 file changed, 27 insertions(+), 20 deletions(-)
diff --git a/tcg-runtime.c b/tcg-runtime.c
index f4bfa9cea6..a025a6f194 100644
--- a/tcg-runtime.c
+++ b/tcg-runtime.c
@@ -147,28 +147,35 @@ uint64_t HELPER(ctpop_i64)(uint64_t arg)
void *HELPER(lookup_tb_ptr)(CPUArchState *env, target_ulong addr)
{
CPUState *cpu = ENV_GET_CPU(env);
- unsigned int addr_hash = tb_jmp_cache_hash_func(addr);
void *code_ptr = NULL;
- TranslationBlock *tb;
-
- tb = atomic_rcu_read(&cpu->tb_jmp_cache[addr_hash]);
- if (likely(tb)) {
- target_ulong cs_base, pc;
- uint32_t flags;
-
- cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
-
- if (likely(tb->pc == addr && tb->cs_base == cs_base &&
- tb->flags == flags)) {
- code_ptr = tb->tc_ptr;
- } else {
- /* If we didn't find it in the jmp_cache we still might
- * find it in the global tb_htable
- */
- tb = tb_htable_lookup(cpu, addr, cs_base, flags);
- if (likely(tb)) {
- atomic_set(&cpu->tb_jmp_cache[addr_hash], tb);
+
+ /* If there is an interrupt pending request or the TCG exit flag
+ * has been set we might as well stop here and return to the main
+ * loop.
+ */
+ if (!cpu->icount_decr.u16.high && !cpu->interrupt_request) {
+ unsigned int addr_hash = tb_jmp_cache_hash_func(addr);
+ TranslationBlock *tb;
+
+ tb = atomic_rcu_read(&cpu->tb_jmp_cache[addr_hash]);
+ if (likely(tb)) {
+ target_ulong cs_base, pc;
+ uint32_t flags;
+
+ cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
+
+ if (likely(tb->pc == addr && tb->cs_base == cs_base &&
+ tb->flags == flags)) {
code_ptr = tb->tc_ptr;
+ } else {
+ /* If we didn't find it in the jmp_cache we still might
+ * find it in the global tb_htable
+ */
+ tb = tb_htable_lookup(cpu, addr, cs_base, flags);
+ if (likely(tb)) {
+ atomic_set(&cpu->tb_jmp_cache[addr_hash], tb);
+ code_ptr = tb->tc_ptr;
+ }
}
}
}
--
2.13.0
- [Qemu-devel] [PATCH v1 0/3] Fixes for TCG hangs, Alex Bennée, 2017/06/14
- [Qemu-devel] [PATCH v1 3/3] tcg-runtime: short-circuit lookup_tb_ptr on IRQs,
Alex Bennée <=
- Re: [Qemu-devel] [PATCH v1 3/3] tcg-runtime: short-circuit lookup_tb_ptr on IRQs, Richard Henderson, 2017/06/14
- Re: [Qemu-devel] [PATCH v1 3/3] tcg-runtime: short-circuit lookup_tb_ptr on IRQs, Paolo Bonzini, 2017/06/14
- Re: [Qemu-devel] [PATCH v1 3/3] tcg-runtime: short-circuit lookup_tb_ptr on IRQs, Richard Henderson, 2017/06/14
- Re: [Qemu-devel] [PATCH v1 3/3] tcg-runtime: short-circuit lookup_tb_ptr on IRQs, Paolo Bonzini, 2017/06/14
- Re: [Qemu-devel] [PATCH v1 3/3] tcg-runtime: short-circuit lookup_tb_ptr on IRQs, Richard Henderson, 2017/06/14
- Re: [Qemu-devel] [PATCH v1 3/3] tcg-runtime: short-circuit lookup_tb_ptr on IRQs, Alex Bennée, 2017/06/14
- Re: [Qemu-devel] [PATCH v1 3/3] tcg-runtime: short-circuit lookup_tb_ptr on IRQs, Richard Henderson, 2017/06/14
- Re: [Qemu-devel] [PATCH v1 3/3] tcg-runtime: short-circuit lookup_tb_ptr on IRQs, Emilio G. Cota, 2017/06/16
- Re: [Qemu-devel] [PATCH v1 3/3] tcg-runtime: short-circuit lookup_tb_ptr on IRQs, Alex Bennée, 2017/06/14
- Re: [Qemu-devel] [PATCH v1 3/3] tcg-runtime: short-circuit lookup_tb_ptr on IRQs, Richard Henderson, 2017/06/14