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[Qemu-devel] [PULL 09/11] cpu-exec: Print to console if the guest is lat
From: |
Paolo Bonzini |
Subject: |
[Qemu-devel] [PULL 09/11] cpu-exec: Print to console if the guest is late |
Date: |
Wed, 6 Aug 2014 18:12:33 +0200 |
From: Sebastian Tanase <address@hidden>
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 and we limit the number of messages to 100.
If desired, this can be changed in cpu-exec.c
Signed-off-by: Sebastian Tanase <address@hidden>
Tested-by: Camille Bégué <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
---
cpu-exec.c | 33 ++++++++++++++++++++++++++++++++-
1 file changed, 32 insertions(+), 1 deletion(-)
diff --git a/cpu-exec.c b/cpu-exec.c
index 68f82b6..3c14502 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -29,6 +29,7 @@
typedef struct SyncClocks {
int64_t diff_clk;
int64_t last_cpu_icount;
+ int64_t realtime_clock;
} SyncClocks;
#if !defined(CONFIG_USER_ONLY)
@@ -37,6 +38,9 @@ typedef struct SyncClocks {
* oscillate around 0.
*/
#define VM_CLOCK_ADVANCE 3000000
+#define THRESHOLD_REDUCE 1.5
+#define MAX_DELAY_PRINT_RATE 2000000000LL
+#define MAX_NB_PRINTS 100
static void align_clocks(SyncClocks *sc, const CPUState *cpu)
{
@@ -68,16 +72,43 @@ static void align_clocks(SyncClocks *sc, const CPUState
*cpu)
}
}
+static void print_delay(const SyncClocks *sc)
+{
+ static float threshold_delay;
+ static int64_t last_realtime_clock;
+ static int nb_prints;
+
+ if (icount_align_option &&
+ sc->realtime_clock - last_realtime_clock >= MAX_DELAY_PRINT_RATE &&
+ nb_prints < MAX_NB_PRINTS) {
+ if ((-sc->diff_clk / (float)1000000000LL > threshold_delay) ||
+ (-sc->diff_clk / (float)1000000000LL <
+ (threshold_delay - THRESHOLD_REDUCE))) {
+ threshold_delay = (-sc->diff_clk / 1000000000LL) + 1;
+ printf("Warning: The guest is now late by %.1f to %.1f seconds\n",
+ threshold_delay - 1,
+ threshold_delay);
+ nb_prints++;
+ last_realtime_clock = sc->realtime_clock;
+ }
+ }
+}
+
static void init_delay_params(SyncClocks *sc,
const CPUState *cpu)
{
if (!icount_align_option) {
return;
}
+ sc->realtime_clock = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
sc->diff_clk = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) -
- qemu_clock_get_ns(QEMU_CLOCK_REALTIME) +
+ sc->realtime_clock +
cpu_get_clock_offset();
sc->last_cpu_icount = cpu->icount_extra + cpu->icount_decr.u16.low;
+
+ /* Print every 2s max if the guest is late. We limit the number
+ of printed messages to NB_PRINT_MAX(currently 100) */
+ print_delay(sc);
}
#else
static void align_clocks(SyncClocks *sc, const CPUState *cpu)
--
1.9.3
- [Qemu-devel] [PULL 00/11] KVM, icount changes for 2014-08-06, Paolo Bonzini, 2014/08/06
- [Qemu-devel] [PULL 02/11] icount: put icount variables into TimerState., Paolo Bonzini, 2014/08/06
- [Qemu-devel] [PULL 03/11] migration: migrate icount fields., Paolo Bonzini, 2014/08/06
- [Qemu-devel] [PULL 04/11] timer: add cpu_icount_to_ns function., Paolo Bonzini, 2014/08/06
- [Qemu-devel] [PULL 01/11] backends: Introduce chr-testdev, Paolo Bonzini, 2014/08/06
- [Qemu-devel] [PULL 05/11] icount: Fix virtual clock start value on ARM, Paolo Bonzini, 2014/08/06
- [Qemu-devel] [PULL 06/11] icount: Add QemuOpts for icount, Paolo Bonzini, 2014/08/06
- [Qemu-devel] [PULL 07/11] icount: Add align option to icount, Paolo Bonzini, 2014/08/06
- [Qemu-devel] [PULL 08/11] cpu-exec: Add sleeping algorithm, Paolo Bonzini, 2014/08/06
- [Qemu-devel] [PULL 09/11] cpu-exec: Print to console if the guest is late,
Paolo Bonzini <=
- [Qemu-devel] [PULL 11/11] target-mips: Ignore unassigned accesses with KVM, Paolo Bonzini, 2014/08/06
- [Qemu-devel] [PULL 10/11] monitor: Add drift info to 'info jit', Paolo Bonzini, 2014/08/06
- Re: [Qemu-devel] [PULL 00/11] KVM, icount changes for 2014-08-06, Peter Maydell, 2014/08/07