Some hypervisors support guest time scaling by given ratio, additional
to the time offset. The guest time is calculated using the formula:
guest time = host time * scaling ratio + time offset
Scaling is useful in case of guest VM migration to a different host
machine.
The scaling parameter is added to timestamp synchronization algorithms.
It is saved in trace.dat file metadata and is used in timestamp
calculations when reading the file.
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
---
include/trace-cmd/trace-cmd.h | 4 +--
lib/trace-cmd/include/trace-tsync-local.h | 11 +++++---
lib/trace-cmd/trace-input.c | 8 +++++-
lib/trace-cmd/trace-timesync.c | 32 +++++++++++++++++------
tracecmd/trace-dump.c | 11 ++++++--
tracecmd/trace-tsync.c | 16 +++++++-----
6 files changed, 60 insertions(+), 22 deletions(-)
diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 9629d074..6a6e4061 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -464,8 +464,8 @@ bool tsync_proto_is_supported(char *proto_name);
void tracecmd_tsync_with_host(struct tracecmd_time_sync *tsync);
void tracecmd_tsync_with_guest(struct tracecmd_time_sync *tsync);
int tracecmd_tsync_get_offsets(struct tracecmd_time_sync *tsync,
- int *count,
- long long **ts, long long **offsets);
+ int *count, long long **ts,
+ long long **offsets, long long **scalings);
void tracecmd_tsync_free(struct tracecmd_time_sync *tsync);
/* --- Plugin handling --- */
diff --git a/lib/trace-cmd/include/trace-tsync-local.h b/lib/trace-cmd/include/trace-tsync-local.h
index 793737e8..492a0a90 100644
--- a/lib/trace-cmd/include/trace-tsync-local.h
+++ b/lib/trace-cmd/include/trace-tsync-local.h
@@ -15,10 +15,15 @@ struct clock_sync_context {
struct tracefs_instance *instance; /* ftrace buffer, used for time sync events */
/* Arrays with calculated time offsets at given time */
- int sync_size; /* Allocated size of sync_ts and sync_offsets */
- int sync_count; /* Number of elements in sync_ts and sync_offsets */
+ int sync_size; /* Allocated size of sync_ts,
+ * sync_offsets and sync_scalings
+ */
+ int sync_count; /* Number of elements in sync_ts,
+ * sync_offsets and sync_scalings
+ */
long long *sync_ts;
long long *sync_offsets;
+ long long *sync_scalings;
/* Identifiers of local and remote time sync peers: cid and port */
unsigned int local_cid;
@@ -32,7 +37,7 @@ int tracecmd_tsync_proto_register(char *proto_name, int accuracy, int roles,
int (*init)(struct tracecmd_time_sync *),
int (*free)(struct tracecmd_time_sync *),
int (*calc)(struct tracecmd_time_sync *,
- long long *, long long *));
+ long long *, long long *, long long *));
int tracecmd_tsync_proto_unregister(char *proto_name);
int ptp_clock_sync_register(void);
diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index af97883e..1ac50f48 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -80,6 +80,7 @@ struct input_buffer_instance {
struct ts_offset_sample {
long long time;
long long offset;
+ long long scaling;
};
struct guest_trace_info {
@@ -1123,12 +1124,14 @@ static inline unsigned long long
timestamp_correction_calc(unsigned long long ts, struct ts_offset_sample *min,
struct ts_offset_sample *max)
{
+ long long scaling = (min->scaling + max->scaling) / 2;
long long offset = ((long long)ts - min->time) *
(max->offset - min->offset);
long long delta = max->time - min->time;
long long tscor = min->offset +
(offset + delta / 2) / delta;
+ ts *= scaling;
if (tscor < 0)
return ts - llabs(tscor);
@@ -2181,7 +2184,9 @@ static void tsync_offset_load(struct tracecmd_input *handle, char *buf)
host->ts_samples[i].time = tep_read_number(handle->pevent,
buf8 + i, 8);
host->ts_samples[i].offset = tep_read_number(handle->pevent,
- buf8 + host->ts_samples_count+i, 8);
+ buf8 + host->ts_samples_count + i, 8);
+ host->ts_samples[i].scaling = tep_read_number(handle->pevent,
+ buf8 + (2 * host->ts_samples_count) + i, 8);
}
qsort(host->ts_samples, host->ts_samples_count,
sizeof(struct ts_offset_sample), tsync_offset_cmp);
@@ -2534,6 +2539,7 @@ static int handle_options(struct tracecmd_input *handle)
* long long array of size [count] of times,
* when the offsets were calculated.
* long long array of size [count] of timestamp offsets.
+ * long long array of size [count] of timestamp scaling ratios.*
*/
if (size < 12 || handle->flags & TRACECMD_FL_IGNORE_DATE)
break;
diff --git a/lib/trace-cmd/trace-timesync.c b/lib/trace-cmd/trace-timesync.c
index 12e00686..1036917e 100644
--- a/lib/trace-cmd/trace-timesync.c
+++ b/lib/trace-cmd/trace-timesync.c
@@ -32,7 +32,8 @@ struct tsync_proto {
int (*clock_sync_init)(struct tracecmd_time_sync *clock_context);
int (*clock_sync_free)(struct tracecmd_time_sync *clock_context);
int (*clock_sync_calc)(struct tracecmd_time_sync *clock_context,
- long long *offset, long long *timestamp);
+ long long *offset, long long *scaling,
+ long long *timestamp);
};
static struct tsync_proto *tsync_proto_list;
@@ -56,7 +57,7 @@ int tracecmd_tsync_proto_register(char *proto_name, int accuracy, int roles,
int (*init)(struct tracecmd_time_sync *),
int (*free)(struct tracecmd_time_sync *),
int (*calc)(struct tracecmd_time_sync *,
- long long *, long long *))
+ long long *, long long *, long long *))
{
struct tsync_proto *proto = NULL;
@@ -113,12 +114,13 @@ bool tsync_proto_is_supported(char *proto_name)
* @count: Returns the number of calculated time offsets
* @ts: Array of size @count containing timestamps of callculated offsets
* @offsets: array of size @count, containing offsets for each timestamp
+ * @scalings: array of size @count, containing scaling ratios for each timestamp
*
* Retuns -1 in case of an error, or 0 otherwise
*/
int tracecmd_tsync_get_offsets(struct tracecmd_time_sync *tsync,
- int *count,
- long long **ts, long long **offsets)
+ int *count, long long **ts,
+ long long **offsets, long long **scalings)
{
struct clock_sync_context *tsync_context;
@@ -131,6 +133,9 @@ int tracecmd_tsync_get_offsets(struct tracecmd_time_sync *tsync,
*ts = tsync_context->sync_ts;
if (offsets)
*offsets = tsync_context->sync_offsets;
+ if (scalings)
+ *scalings = tsync_context->sync_scalings;
+
return 0;
}
@@ -349,8 +354,10 @@ void tracecmd_tsync_free(struct tracecmd_time_sync *tsync)
free(tsync_context->sync_ts);
free(tsync_context->sync_offsets);
+ free(tsync_context->sync_scalings);
tsync_context->sync_ts = NULL;
tsync_context->sync_offsets = NULL;
+ tsync_context->sync_scalings = NULL;
tsync_context->sync_count = 0;
tsync_context->sync_size = 0;
pthread_mutex_destroy(&tsync->lock);
@@ -362,10 +369,11 @@ int tracecmd_tsync_send(struct tracecmd_time_sync *tsync,
struct tsync_proto *proto)
{
long long timestamp = 0;
+ long long scaling = 0;
long long offset = 0;
int ret;
- ret = proto->clock_sync_calc(tsync, &offset, ×tamp);
+ ret = proto->clock_sync_calc(tsync, &offset, &scaling, ×tamp);
return ret;
}
@@ -413,18 +421,20 @@ static int tsync_get_sample(struct tracecmd_time_sync *tsync,
struct tsync_proto *proto, int array_step)
{
struct clock_sync_context *clock;
+ long long *sync_scalings = NULL;
long long *sync_offsets = NULL;
long long *sync_ts = NULL;
long long timestamp = 0;
+ long long scaling = 0;
long long offset = 0;
int ret;
- ret = proto->clock_sync_calc(tsync, &offset, ×tamp);
+ ret = proto->clock_sync_calc(tsync, &offset, &scaling, ×tamp);
if (ret) {
warning("Failed to synchronize timestamps with guest");
return -1;
}
- if (!offset || !timestamp)
+ if (!offset || !timestamp || !scaling)
return 0;
clock = tsync->context;
if (clock->sync_count >= clock->sync_size) {
@@ -432,18 +442,24 @@ static int tsync_get_sample(struct tracecmd_time_sync *tsync,
(clock->sync_size + array_step) * sizeof(long long));
sync_offsets = realloc(clock->sync_offsets,
(clock->sync_size + array_step) * sizeof(long long));
- if (!sync_ts || !sync_offsets) {
+ sync_scalings = realloc(clock->sync_scalings,
+ (clock->sync_size + array_step) * sizeof(long long));
+
+ if (!sync_ts || !sync_offsets || !sync_scalings) {
free(sync_ts);
free(sync_offsets);
+ free(sync_scalings);
return -1;
}
clock->sync_size += array_step;
clock->sync_ts = sync_ts;
clock->sync_offsets = sync_offsets;
+ clock->sync_scalings = sync_scalings;
}
clock->sync_ts[clock->sync_count] = timestamp;
clock->sync_offsets[clock->sync_count] = offset;
+ clock->sync_scalings[clock->sync_count] = scaling;
clock->sync_count++;
return 0;
diff --git a/tracecmd/trace-dump.c b/tracecmd/trace-dump.c
index 5642f12a..0117f979 100644
--- a/tracecmd/trace-dump.c
+++ b/tracecmd/trace-dump.c
@@ -369,6 +369,7 @@ static void dump_option_xlong(int fd, int size, char *desc)
static void dump_option_timeshift(int fd, int size)
{
+ long long *scalings = NULL;
long long *offsets = NULL;
long long *times = NULL;
long long trace_id;
@@ -397,19 +398,25 @@ static void dump_option_timeshift(int fd, int size)
offsets = calloc(count, sizeof(long long));
if (!offsets)
goto out;
+ scalings = calloc(count, sizeof(long long));
+ if (!scalings)
+ goto out;
for (i = 0; i < count; i++)
read_file_number(fd, times + i, 8);
for (i = 0; i < count; i++)
read_file_number(fd, offsets + i, 8);
+ for (i = 0; i < count; i++)
+ read_file_number(fd, scalings + i, 8);
for (i = 0; i < count; i++)
- do_print(OPTIONS, "\t%lld %lld [offset @ time]\n",
- offsets[i], times[i]);
+ do_print(OPTIONS, "\t%lld * %lld %lld [offset * scaling @ time]\n",
+ offsets[i], scalings[1], times[i]);
out:
free(times);
free(offsets);
+ free(scalings);
}
void dump_option_guest(int fd, int size)
diff --git a/tracecmd/trace-tsync.c b/tracecmd/trace-tsync.c
index bc5c744e..6d0a9e85 100644
--- a/tracecmd/trace-tsync.c
+++ b/tracecmd/trace-tsync.c
@@ -132,16 +132,18 @@ out:
static void write_guest_time_shift(struct buffer_instance *instance)
{
struct tracecmd_output *handle;
- struct iovec vector[4];
- long long *offsets;
- long long *ts;
+ struct iovec vector[5];
+ long long *scalings = NULL;
+ long long *offsets = NULL;
+ long long *ts = NULL;
const char *file;
int count;
int ret;
int fd;
- ret = tracecmd_tsync_get_offsets(&instance->tsync, &count, &ts, &offsets);
- if (ret < 0 || !count || !ts || !offsets)
+ ret = tracecmd_tsync_get_offsets(&instance->tsync, &count,
+ &ts, &offsets, &scalings);
+ if (ret < 0 || !count || !ts || !offsets || !scalings)
return;
file = instance->output_file;
@@ -157,7 +159,9 @@ static void write_guest_time_shift(struct buffer_instance *instance)
vector[2].iov_base = ts;
vector[3].iov_len = 8 * count;
vector[3].iov_base = offsets;
- tracecmd_add_option_v(handle, TRACECMD_OPTION_TIME_SHIFT, vector, 4);
+ vector[4].iov_len = 8 * count;
+ vector[4].iov_base = scalings;
+ tracecmd_add_option_v(handle, TRACECMD_OPTION_TIME_SHIFT, vector, 5);
tracecmd_append_options(handle);
tracecmd_output_close(handle);
#ifdef TSYNC_DEBUG
--
2.26.2
|