If the align option is enabled, we print to the user whenever
the guest clock is behind the host clock in order for he/she
to have a hint about the actual performance. The maximum
print interval is 2s so as not to spam the console.
Signed-off-by: Sebastian Tanase <sebastian.tan...@openwide.fr>
Tested-by: Camille Bégué <camille.be...@openwide.fr>
---
cpu-exec.c | 32 +++++++++++++++++++++++++++++++-
1 file changed, 31 insertions(+), 1 deletion(-)
diff --git a/cpu-exec.c b/cpu-exec.c
index 5a3bc5e..a386592 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -216,6 +216,8 @@ static void cpu_handle_debug_exception(CPUArchState *env)
* oscillate around 0.
*/
#define VM_CLOCK_ADVANCE 3000000
+#define THRESHOLD_REDUCE 1.5
+#define MAX_DELAY_PRINT_RATE 2
static int64_t delay_host(int64_t diff_clk)
{
@@ -257,6 +259,29 @@ static int64_t align_clocks(int64_t diff_clk, int64_t
*oic, CPUState *cpu)
return diff_clk;
}
+static void print_delay(int64_t diff_clk, int64_t realtime_clock)
+{
+ static float threshold_delay;
+ static int64_t last_realtime_clock;
+
+ if ((realtime_clock - last_realtime_clock) / 1000000000LL
+ >= MAX_DELAY_PRINT_RATE) {
+ if (-diff_clk / (float)1000000000LL > threshold_delay) {
+ threshold_delay = (-diff_clk / 1000000000LL) + 1;
+ printf("Warning: The guest is late by %.1f to %.1f seconds\n",
+ threshold_delay - 1,
+ threshold_delay);
+ } else if (-diff_clk / (float)1000000000LL <
+ (threshold_delay - THRESHOLD_REDUCE)) {
+ threshold_delay = (-diff_clk / 1000000000LL) + 1;
+ printf("Warning: The guest has reduced the delay and is now
"
+ "late by %.1f to %.1f seconds\n",
+ threshold_delay - 1,
+ threshold_delay);
+ }
+ last_realtime_clock = realtime_clock;
+ }
+}
#endif /* CONFIG USER ONLY */
/* main execution loop */
@@ -278,6 +303,8 @@ int cpu_exec(CPUArchState *env)
uint8_t *tc_ptr;
uintptr_t next_tb;
#if !(defined(CONFIG_USER_ONLY))
+ /* Print delay control */
+ static int64_t realtime_clock;
/* Delay algorithm */
int64_t diff_clk, original_instr_counter;
#endif
@@ -342,9 +369,12 @@ int cpu_exec(CPUArchState *env)
This delay includes the delay of the last cycle, so
what we have to do is sleep until it is 0. As for the
advance/delay we gain here, we try to fix it next time. */
+ realtime_clock = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
diff_clk = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) -
- qemu_clock_get_ns(QEMU_CLOCK_REALTIME) + clocks_offset;
+ realtime_clock + clocks_offset;
original_instr_counter = cpu->icount_extra + cpu->icount_decr.u16.low;
+ /* Print (every 2s max) if the guest is behind the host */
+ print_delay(diff_clk, realtime_clock);
}
#endif
/* prepare setjmp context for exception handling */
--
2.0.0.rc2
