Re: [PATCH 08/10] perf tool: Unify handling of features when writing feature section

[Robert Richter <robert.richter@amd.com>]

On 06.12.11 11:36:30, Arnaldo Carvalho de Melo wrote:
> Em Tue, Dec 06, 2011 at 11:32:38AM +0100, Robert Richter escreveu:
> > Also moving special code for HEADER_BUILD_ID out to write_build_id().
> 
> For this one I just would add a big fat warning that if there are
> build-ids on the system but the table can't be written, then extreme
> care has to be taken when doing a perf report.
> 
> I.e. one has to be completely sure that the binaries hasn't changed if
> not validating the build-ids.
> 
> If you fix that please add this warning as well when no build-ids are
> found, which hopefully is the odd case these days as all distros I'm
> aware of have build-ids in all DSOs.

What about the following change in addition? perf record then still
stops with an error, but --no-buildid could be used to proceed anyway:

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 766fa0a..80e08ca 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -493,6 +493,13 @@ static int __cmd_record(struct perf_record *rec, int argc, const char **argv)
                        return err;
        }
 
+       if (!no_buildid
+           && !perf_header__has_feat(&session->header, HEADER_BUILD_ID)) {
+               pr_err("Couldn't generate buildids. "
+                      "Use --no-buildid option to profile anyway.\n");
+               return -1;
+       }
+
        rec->post_processing_offset = lseek(output, 0, SEEK_CUR);
 
        machine = perf_session__find_host_machine(session);


-Robert

-- 
Advanced Micro Devices, Inc.
Operating System Research Center