diff mbox series

[PULL,24/45] icount: improve exec nocache usage

Message ID 20201215175445.1272776-25-pbonzini@redhat.com
State New
Headers show
Series [PULL,01/45] remove preconfig state | expand

Commit Message

Paolo Bonzini Dec. 15, 2020, 5:54 p.m. UTC 
From: Pavel Dovgalyuk <pavel.dovgalyuk@ispras.ru>

cpu-exec tries to execute TB without caching when current
icount budget is over. But sometimes refilled budget is big
enough to try executing cached blocks.
This patch checks that instruction budget is big enough
for next block execution instead of just running cpu_exec_nocache.
It halves the number of calls of cpu_exec_nocache function
during tested OS boot scenario.

Signed-off-by: Pavel Dovgalyuk <pavel.dovgalyuk@ispras.ru>
Message-Id: <160741865825.348476.7169239332367828943.stgit@pasha-ThinkPad-X280>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 accel/tcg/cpu-exec.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c
index 58aea605d8..251b340fb9 100644
--- a/accel/tcg/cpu-exec.c
+++ b/accel/tcg/cpu-exec.c
@@ -685,7 +685,7 @@  static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb,
     insns_left = MIN(0xffff, cpu->icount_budget);
     cpu_neg(cpu)->icount_decr.u16.low = insns_left;
     cpu->icount_extra = cpu->icount_budget - insns_left;
-    if (!cpu->icount_extra) {
+    if (!cpu->icount_extra && insns_left < tb->icount) {
         /* Execute any remaining instructions, then let the main loop
          * handle the next event.
          */