When reading a trace file, detect and store the timestamp of the first
recorded event. A new API is introduced to get the first ts from an input
handler:
tracecmd_get_first_ts()
The first ts can be used by the library users to align timestamps of the
events, when displaying them.
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
---
include/trace-cmd/trace-cmd.h | 1 +
lib/trace-cmd/trace-input.c | 23 +++++++++++++++++++++++
2 files changed, 24 insertions(+)
diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
index 162cd318..022720b0 100644
--- a/include/trace-cmd/trace-cmd.h
+++ b/include/trace-cmd/trace-cmd.h
@@ -37,6 +37,7 @@ int tracecmd_get_guest_cpumap(struct tracecmd_input *handle,
unsigned long long trace_id,
const char **name,
int *vcpu_count, const int **cpu_pid);
+unsigned long long tracecmd_get_first_ts(struct tracecmd_input *handle);
int tracecmd_buffer_instances(struct tracecmd_input *handle);
const char *tracecmd_buffer_instance_name(struct tracecmd_input *handle, int indx);
struct tracecmd_input *tracecmd_buffer_instance_handle(struct tracecmd_input *handle, int indx);
diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
index bacf9ccf..284f25e8 100644
--- a/lib/trace-cmd/trace-input.c
+++ b/lib/trace-cmd/trace-input.c
@@ -61,6 +61,7 @@ struct cpu_data {
unsigned long long offset;
unsigned long long size;
unsigned long long timestamp;
+ unsigned long long first_ts;
struct list_head page_maps;
struct page_map *page_map;
struct page **pages;
@@ -2273,6 +2274,7 @@ static int init_cpu(struct tracecmd_input *handle, int cpu)
if (update_page_info(handle, cpu))
goto fail;
+ cpu_data->first_ts = cpu_data->timestamp;
return 0;
fail:
@@ -4072,6 +4074,27 @@ unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle)
return handle->trace_id;
}
+/**
+ * tracecmd_get_first_ts - get the timestamp of the first recorded event
+ * @handle: input handle for the trace.dat file
+ *
+ * Returns the timestamp of the first recorded event
+ */
+unsigned long long tracecmd_get_first_ts(struct tracecmd_input *handle)
+{
+ unsigned long long ts = 0;
+ bool first = true;
+ int i;
+
+ for (i = 0; i < handle->cpus; i++) {
+ if (first || ts > handle->cpu_data[i].first_ts)
+ ts = handle->cpu_data[i].first_ts;
+ first = false;
+ }
+
+ return ts;
+}
+
/**
* tracecmd_get_guest_cpumap - get the mapping of guest VCPU to host process
* @handle: input handle for the trace.dat file
--
2.30.2
|