On Fri, 10 Dec 2021 12:54:32 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx> wrote:
I'm going to keep mentioning spacing ;-)
> Extended the BUFFER trace option in trace file version 7 with CPU
> flyrecord trace metadata. In the version 6 of the trace file, this metadata
> is located at several places in the file. Part of the metadata is only for
> the top trace instance, thus limiting per-instance configuration. Moving
> all CPU trace related metadata in the BUFFER option simplifies the parsing
> and makes per-instance configuration more flexible. In the new file
> structure, the top instance is treated as any other instances.
space
> The format of the extended BUFFER option is:
> - offset of the buffer in the trace file
> - name of the buffer
> - trace clock, used in this buffer for events timestamps
> - count of CPUs with trace data
> - array, describing each CPU with trace data:
> - CPU id
> - offset of CPU trace data in the trace file
> - size of the recorded CPU trace data
>
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
> ---
> lib/trace-cmd/trace-output.c | 191 +++++++++++++++++++++++++----------
> 1 file changed, 137 insertions(+), 54 deletions(-)
>
> diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
> index 59093be2..6e40c929 100644
> --- a/lib/trace-cmd/trace-output.c
> +++ b/lib/trace-cmd/trace-output.c
> @@ -1675,7 +1675,7 @@ int tracecmd_append_options(struct tracecmd_output *handle)
> }
>
> static struct tracecmd_option *
> -add_buffer_option(struct tracecmd_output *handle, const char *name, int cpus)
> +add_buffer_option_v6(struct tracecmd_output *handle, const char *name, int cpus)
> {
> struct tracecmd_option *option;
> char *buf;
> @@ -1725,8 +1725,11 @@ int tracecmd_write_buffer_info(struct tracecmd_output *handle)
> struct tracecmd_option *option;
> struct tracecmd_buffer *buf;
>
> + if (HAS_SECTIONS(handle))
> + return 0;
> +
> list_for_each_entry(buf, &handle->buffers, list) {
> - option = add_buffer_option(handle, buf->name, buf->cpus);
> + option = add_buffer_option_v6(handle, buf->name, buf->cpus);
> if (!option)
> return -1;
> buf->option = option;
> @@ -1777,6 +1780,98 @@ int tracecmd_write_cmdlines(struct tracecmd_output *handle)
> return 0;
> }
>
> +static char *get_clock(struct tracecmd_output *handle)
> +{
> + struct tracefs_instance *inst;
> +
> + if (handle->trace_clock)
> + return handle->trace_clock;
> +
> + /*
> + * If no clock is set on this handle, get the trace clock of
> + * the top instance in the handle's tracing dir
> + */
> + inst = tracefs_instance_alloc(handle->tracing_dir, NULL);
> + if (!inst)
> + return NULL;
> + handle->trace_clock = tracefs_get_clock(inst);
Why allocate an instance, doesn't:
tracefs_get_clock(NULL);
do the same? (at least the man page says it does).
Or are you worried that this has to do something with the tracing_dir?
But do we care?
> + tracefs_instance_free(inst);
> + return handle->trace_clock;
> +}
> +
> +__hidden struct tracecmd_option *
> +out_add_buffer_option_v7(struct tracecmd_output *handle, const char *name,
Again, I think it's safe to remove all the references to v7, and just
have that be the default.
> + unsigned short id, unsigned long long data_offset,
> + int cpus, struct data_file_write *cpu_data)
> +{
> + struct tracecmd_option *option;
> + int i, j = 0, k = 0;
> + int *cpu_ids = NULL;
> + struct iovec *vect;
> + char *clock;
> +
> + if (!HAS_SECTIONS(handle))
> + return NULL;
> +
> + clock = get_clock(handle);
> +
> + /* Buffer flyrecord option, v7:
Including here (no need to say "v7")
> + * - trace data offset in the file
> + * - buffer name
> + * - buffer clock
> + * - CPU count
> + * - for each CPU:
> + * - CPU id
> + * - CPU trace data offset in the file
> + * - CPU trace data size
> + */
> +
> + /* Buffer latency option, v7:
and here.
> + * - trace data offset in the file
> + * - buffer name
> + * - buffer clock
> + */
> +
> + vect = calloc(5 + (cpus * 3), sizeof(struct iovec));
What's with the magical 5 and 3 numbers above?
As from the comments above, I only count 4 and 3.
4 : offset, name, clock, count
3 : cpu offset, name, clock
Could include the above in a comment too.
-- Steve
> + if (!vect)
> + return NULL;
> + if (cpus) {
> + cpu_ids = calloc(cpus, sizeof(int));
> + if (!cpu_ids) {
> + free(vect);
> + return NULL;
> + }
> + }
> + vect[j].iov_base = (void *) &data_offset;
> + vect[j++].iov_len = 8;
> + vect[j].iov_base = (void *) name;
> + vect[j++].iov_len = strlen(name) + 1;
> + vect[j].iov_base = (void *) clock;
> + vect[j++].iov_len = strlen(clock) + 1;
> + if (id == TRACECMD_OPTION_BUFFER) {
> + vect[j].iov_base = (void *) &k;
> + vect[j++].iov_len = 4;
> + for (i = 0; i < cpus; i++) {
> + if (!cpu_data[i].file_size)
> + continue;
> + cpu_ids[i] = i;
> + vect[j].iov_base = &cpu_ids[i];
> + vect[j++].iov_len = 4;
> + vect[j].iov_base = &cpu_data[i].data_offset;
> + vect[j++].iov_len = 8;
> + vect[j].iov_base = &cpu_data[i].write_size;
> + vect[j++].iov_len = 8;
> + k++;
> + }
> + }
> +
> + option = tracecmd_add_option_v(handle, id, vect, j);
> + free(vect);
> + free(cpu_ids);
> +
> + return option;
> +}
> +
> struct tracecmd_output *tracecmd_create_file_latency(const char *output_file, int cpus)
> {
> struct tracecmd_output *handle;
> @@ -1847,8 +1942,8 @@ out:
> return ret;
> }
|