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authorAlex Bennée <alex.bennee@linaro.org>2017-04-05 12:35:48 +0100
committerAlex Bennée <alex.bennee@linaro.org>2017-04-10 10:23:38 +0100
commiteda5f7c6a147c8eb927a6198ec48fe677cb079b3 (patch)
treeaa79ed0426be8641ed4aefc8335115c0a5165a71
parent512d3c807177b5cfff6b5a4925d71ae1b5521093 (diff)
cpu-exec: update icount after each TB_EXIT
There is no particular reason we shouldn't update the global system icount time as we exit each TranslationBlock run. This ensures the main-loop doesn't have to wait until we exit to the outer loop for executed instructions to be credited to timer_state. The prepare_icount_for_run function is slightly tweaked to match the logic we run in cpu_loop_exec_tb. Based on Paolo's original suggestion. Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
-rw-r--r--cpu-exec.c14
-rw-r--r--cpus.c18
2 files changed, 12 insertions, 20 deletions
diff --git a/cpu-exec.c b/cpu-exec.c
index 748cb66bca..63a56d0407 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -600,13 +600,13 @@ static inline void cpu_loop_exec_tb(CPUState *cpu, TranslationBlock *tb,
/* Instruction counter expired. */
assert(use_icount);
#ifndef CONFIG_USER_ONLY
- if (cpu->icount_extra) {
- /* Refill decrementer and continue execution. */
- cpu->icount_extra += insns_left;
- insns_left = MIN(0xffff, cpu->icount_extra);
- cpu->icount_extra -= insns_left;
- cpu->icount_decr.u16.low = insns_left;
- } else {
+ /* Ensure global icount has gone forward */
+ cpu_update_icount(cpu);
+ /* Refill decrementer and continue execution. */
+ insns_left = MIN(0xffff, cpu->icount_budget);
+ cpu->icount_decr.u16.low = insns_left;
+ cpu->icount_extra = cpu->icount_budget - insns_left;
+ if (!cpu->icount_extra) {
/* Execute any remaining instructions, then let the main loop
* handle the next event.
*/
diff --git a/cpus.c b/cpus.c
index a5125d7167..9c8bd2c991 100644
--- a/cpus.c
+++ b/cpus.c
@@ -1211,8 +1211,7 @@ static void handle_icount_deadline(void)
static void prepare_icount_for_run(CPUState *cpu)
{
if (use_icount) {
- int64_t count;
- int decr;
+ int insns_left;
/* These should always be cleared by process_icount_data after
* each vCPU execution. However u16.high can be raised
@@ -1221,17 +1220,10 @@ static void prepare_icount_for_run(CPUState *cpu)
g_assert(cpu->icount_decr.u16.low == 0);
g_assert(cpu->icount_extra == 0);
-
- count = tcg_get_icount_limit();
-
- /* To calculate what we have executed so far we need to know
- * what we originally budgeted to run this cycle */
- cpu->icount_budget = count;
-
- decr = (count > 0xffff) ? 0xffff : count;
- count -= decr;
- cpu->icount_decr.u16.low = decr;
- cpu->icount_extra = count;
+ cpu->icount_budget = tcg_get_icount_limit();
+ insns_left = MIN(0xffff, cpu->icount_budget);
+ cpu->icount_decr.u16.low = insns_left;
+ cpu->icount_extra = cpu->icount_budget - insns_left;
}
}