Em Mon, Aug 02, 2021 at 11:41:45PM +0800, Leo Yan escreveu:

On Thu, Jul 29, 2021 at 04:58:05PM +0100, James Clark wrote:

quoted

Currently decode will silently fail if no binary data is available for
the decode. This is made worse if only partial data is available because
the decode will appear to work, but any trace from that missing DSO will
silently not be generated.

Add a UI popup once if there is any data missing, and then warn in the
bottom left for each individual DSO that's missing.

Signed-off-by: James Clark <redacted>
---
 tools/perf/util/cs-etm.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
index 32ad92d3e454..e6851260d059 100644
--- a/tools/perf/util/cs-etm.c
+++ b/tools/perf/util/cs-etm.c

@@ -746,8 +746,16 @@ static u32 cs_etm__mem_access(struct cs_etm_queue *etmq, u8 trace_chan_id,
 
 	len = dso__data_read_offset(al.map->dso, machine, offset, buffer, size);
 
-	if (len <= 0)
+	if (len <= 0) {
+		ui__warning_once("CS ETM Trace: Missing DSO. Use 'perf archive' to export data from the traced system.\n");
+		if (!al.map->dso->auxtrace_warned) {
+			pr_err("CS ETM Trace: Debug data not found for address %#"PRIx64" in %s\n",
+				    address,
+				    al.map->dso->long_name ? al.map->dso->long_name : "Unknown");
+			al.map->dso->auxtrace_warned = true;
+		}

This is very useful.

Just one comment: in particularly if the perf fails to find the kernel
symbols, the user needs to enable config "CONFIG_PROC_KCORE=y" or
specify option "-k /path/to/vmlinux".  In this case, using 'perf
archive' is not helpful.  So I think the UI warning can be imporved
like:

        ui__warning_once("CS ETM Trace: Missing DSO. Use 'perf archive' to export data from the traced system.\n"
                         " Enable CONFIG_PROC_KCORE or use option '-k /path/to/vmlinux' for kernel symbols\n");

one can also use debuginfod-client, which, as time passes, probably will
be the main way of finding DSOs now that we have build-ids in
PERF_RECORD_MMAP2 and debuginfod servers such as:

export DEBUGINFOD_URLS=https://debuginfod.fedoraproject.org/

https://fedoraproject.org/wiki/Debuginfod
 

With this improvement, the patch looks good to me:

Reviewed-by: Leo Yan <redacted>

Does this apply to the other 5 patches in this series?

- Arnaldo
 

quoted

 		return 0;
+	}
 
 	return len;
 }
-- 
2.28.0

-- 

- Arnaldo