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[Qemu-devel] [RFC PATCH V4 5/6] cpu_exec: Print to console if the guest
From: |
Sebastian Tanase |
Subject: |
[Qemu-devel] [RFC PATCH V4 5/6] cpu_exec: Print to console if the guest is late |
Date: |
Wed, 16 Jul 2014 14:18:05 +0200 |
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>
Conflicts:
cpu-exec.c
---
cpu-exec.c | 39 ++++++++++++++++++++++++++++++++++-----
1 file changed, 34 insertions(+), 5 deletions(-)
diff --git a/cpu-exec.c b/cpu-exec.c
index 9ed6ac1..b62df15 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -29,6 +29,7 @@
typedef struct SyncClocks {
int64_t diff_clk;
int64_t original_instr_counter;
+ 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 2
+#define MAX_NB_PRINTS 100
static int64_t delay_host(int64_t diff_clk)
{
@@ -80,6 +84,28 @@ static void align_clocks(SyncClocks *sc, const CPUState *cpu)
sc->diff_clk = delay_host(sc->diff_clk);
}
+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) / 1000000000LL
+ >= 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)
{
@@ -87,15 +113,18 @@ static void init_delay_params(SyncClocks *sc,
if (!icount_align_option) {
return;
}
- int64_t realtime_clock_value, virtual_clock_value;
- realtime_clock_value = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
- virtual_clock_value = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+ sc->realtime_clock = qemu_clock_get_ns(QEMU_CLOCK_REALTIME);
/* Compute offset between the 2 clocks. */
if (!clocks_offset) {
- clocks_offset = realtime_clock_value - virtual_clock_value;
+ clocks_offset = sc->realtime_clock -
+ qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
}
- sc->diff_clk = virtual_clock_value - realtime_clock_value + clocks_offset;
+ sc->diff_clk = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) -
+ sc->realtime_clock + clocks_offset;
sc->original_instr_counter = 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)
--
2.0.0.rc2
[Qemu-devel] [RFC PATCH V4 5/6] cpu_exec: Print to console if the guest is late,
Sebastian Tanase <=
[Qemu-devel] [RFC PATCH V4 2/6] icount: Add align option to icount, Sebastian Tanase, 2014/07/16
Re: [Qemu-devel] [RFC PATCH V4 0/6] icount: Implement delay algorithm between guest and host clocks, Paolo Bonzini, 2014/07/16
- Re: [Qemu-devel] [RFC PATCH V4 0/6] icount: Implement delay algorithm between guest and host clocks, Sebastian Tanase, 2014/07/22
- Re: [Qemu-devel] [RFC PATCH V4 0/6] icount: Implement delay algorithm between guest and host clocks, Paolo Bonzini, 2014/07/22
- Re: [Qemu-devel] [RFC PATCH V4 0/6] icount: Implement delay algorithm between guest and host clocks, Sebastian Tanase, 2014/07/22
- Re: [Qemu-devel] [RFC PATCH V4 0/6] icount: Implement delay algorithm between guest and host clocks, Paolo Bonzini, 2014/07/22
- Re: [Qemu-devel] [RFC PATCH V4 0/6] icount: Implement delay algorithm between guest and host clocks, Sebastian Tanase, 2014/07/22
- Re: [Qemu-devel] [RFC PATCH V4 0/6] icount: Implement delay algorithm between guest and host clocks, Paolo Bonzini, 2014/07/22
Re: [Qemu-devel] [RFC PATCH V4 0/6] icount: Implement delay algorithm between guest and host clocks, Luiz Capitulino, 2014/07/16