On 07/11/2014 12:36, Pavel Dovgaluk wrote:
From: Paolo Bonzini [mailto:pbonz...@redhat.com]
On 07/11/2014 11:32, Pavel Dovgalyuk wrote:
Replay uses number of executed instructions to determine corrent events
injection moments. This patch introduces new function for querying the
instructions counter.
Signed-off-by: Pavel Dovgalyuk <pavel.dovga...@ispras.ru>
---
cpus.c | 26 +++++++++++++++++++++++---
include/qemu/timer.h | 1 +
2 files changed, 24 insertions(+), 3 deletions(-)
diff --git a/cpus.c b/cpus.c
index 7e8c507..2ec6d75 100644
--- a/cpus.c
+++ b/cpus.c
@@ -136,8 +136,7 @@ typedef struct TimersState {
static TimersState timers_state;
-/* Return the virtual CPU time, based on the instruction counter. */
-static int64_t cpu_get_icount_locked(void)
+static int64_t cpu_get_instructions_counter_locked(void)
{
int64_t icount;
CPUState *cpu = current_cpu;
@@ -145,10 +144,31 @@ static int64_t cpu_get_icount_locked(void)
icount = timers_state.qemu_icount;
if (cpu) {
if (!cpu_can_do_io(cpu)) {
- fprintf(stderr, "Bad clock read\n");
+ fprintf(stderr, "Bad icount read\n");
+ exit(1);
}
icount -= (cpu->icount_decr.u16.low + cpu->icount_extra);
}
+ return icount;
+}
+
+int64_t cpu_get_instructions_counter(void)
+{
+ /* This function calls are synchnonized to timer changes,
+ calling cpu_get_instructions_counter_locked without lock is safe */
+ int64_t icount = timers_state.qemu_icount;
+ CPUState *cpu = current_cpu;
+
+ if (cpu) {
+ icount -= (cpu->icount_decr.u16.low + cpu->icount_extra);
+ }
+ return icount;
+}
This is the same as Frederic's QEMU_CLOCK_ICOUNT clock, right? Any
reason why one is better than the other?
Not really. Frederic's QEMU_CLOCK_ICOUNT is measured in nanoseconds.
And this counter is measured in instructions.
Pavel Dovgalyuk
So you transformed your implementation to use icount?
I didn't saw that in the cover letter.
I guess you replay event's according to the current instruction?
I implemented icount clock with the QEMUTimer API so a callback can be
notified during the replay at the right instruction.
By the way do you have a git tree somewhere where I can get the patches?
Fred