On Wed, Mar 31, 2021 at 06:42:48AM -0400, Nicholas Fraser wrote:
> From ddcfd620e7cad4100d0076090c4b39dba8aeead3 Mon Sep 17 00:00:00 2001
> From: Nicholas Fraser <[email protected]>
> Date: Wed, 31 Mar 2021 06:10:00 -0400
> Subject: [PATCH] perf data: Add JSON export
no need to add headers again in here
>
> This adds a feature to export perf data to JSON. It uses a minimal
> inline JSON encoding, no external dependencies. Currently it only
> outputs some headers and sample metadata but it's easily extensible.
>
> Use it like this:
>
> perf data convert --to-json out.json
please add similar output summary message we have for CTF conversion:
[ perf data convert: Converted 'perf.data' into CTF data 'data' ]
[ perf data convert: Converted and wrote 0.000 MB (10 samples) ]
also I will not push hard for test, becase we don't have any for CTF ;-)
but if you could think of any, that'd be great
> +
> +static void output_headers(struct perf_session *session, struct convert_json
> *c)
> +{
> + struct stat st;
> + struct perf_header *header = &session->header;
> + int ret;
> + int fd = perf_data__fd(session->data);
> + int i;
> + bool first;
> +
> + fprintf(c->out, "\n\t\t\t\"header-version\": %u", header->version);
> +
> + ret = fstat(fd, &st);
> + if (ret >= 0) {
> + time_t stctime = st.st_mtime;
> + char buf[256];
> +
> + strftime(buf, sizeof(buf), "%FT%TZ", gmtime(&stctime));
> + fprintf(c->out, ",\n\t\t\t\"captured-on\": \"%s\"", buf);
> + } else {
> + pr_debug("Failed to get mtime of source file, not writing
> \"captured-on\"");
> + }
> +
> + fprintf(c->out, ",\n\t\t\t\"data-offset\": %" PRIu64,
> header->data_offset);
> + fprintf(c->out, ",\n\t\t\t\"data-size\": %" PRIu64, header->data_size);
> + fprintf(c->out, ",\n\t\t\t\"feat-offset\": %" PRIu64,
> header->feat_offset);
I was wondering how to make this \t mess more readable,
how about you define function like output_json:
output_json(FILE, level, field, format, ...);
and use it:
output_json(c->out, 3, "data-offset", "PRIu64", header->data_offset);
output_json(c->out, 3, "data-size", "PRIu64", header->data_size);
output_json(c->out, 3, "feat-offset", PRIu64, header->feat_offset);
similar way as we do for pr_debug -> eprintf
SNIP
> +
> + fd = open(output_name, O_CREAT | O_WRONLY | (opts->force ? 0 : O_EXCL),
> 0666);
> + if (fd == -1) {
> + if (errno == EEXIST)
> + pr_err("Output file exists. Use --force to overwrite
> it.\n");
> + else
> + pr_err("Error opening output file!\n");
> + return -1;
> + }
> +
> + c.out = fdopen(fd, "w");
> + if (!c.out) {
> + fprintf(stderr, "Error opening output file!\n");
> + return -1;
> + }
> +
> + session = perf_session__new(&data, false, &c.tool);
> + if (IS_ERR(session)) {
> + fprintf(stderr, "Error creating perf session!\n");
> + return -1;
here we should close c.out and call perf_session__delete,
we normaly do goto to the end of the function in this case
> + }
> +
> + if (symbol__init(&session->header.env) < 0) {
> + fprintf(stderr, "Symbol init error!\n");
> + return -1;
> + }
> +
> + // Version number for future-proofing. Most additions should be able to
> be
> + // done in a backwards-compatible way so this should only need to be
> bumped
> + // if some major breaking change must be made.
> + fprintf(c.out, "{\n\t\"linux-perf-json-version\": 1,");
> +
> + // Output headers
> + fprintf(c.out, "\n\t\"headers\": {");
> + output_headers(session, &c);
> + fprintf(c.out, "\n\t},");
> +
> + // Output samples
> + fprintf(c.out, "\n\t\"samples\": [");
> + perf_session__process_events(session);
> + fprintf(c.out, "\n\t]\n}\n");
> +
you need to close c.out
> + perf_session__delete(session);
> + return 0;
> +}
> diff --git a/tools/perf/util/data-convert.h b/tools/perf/util/data-convert.h
> index feab5f114e37..1b4c5f598415 100644
> --- a/tools/perf/util/data-convert.h
> +++ b/tools/perf/util/data-convert.h
> @@ -2,10 +2,20 @@
> #ifndef __DATA_CONVERT_H
> #define __DATA_CONVERT_H
>
> +#include <stdbool.h>
> +
> struct perf_data_convert_opts {
> bool force;
> bool all;
> bool tod;
> };
>
> +#ifdef HAVE_LIBBABELTRACE_SUPPORT
> +int bt_convert__perf2ctf(const char *input_name, const char *to_ctf,
> + struct perf_data_convert_opts *opts);
> +#endif /* HAVE_LIBBABELTRACE_SUPPORT */
> +
> +int bt_convert__perf2json(const char *input_name, const char *to_ctf,
> + struct perf_data_convert_opts *opts);
> +
> #endif /* __DATA_CONVERT_H */
great, thanks for this
jirka
