Re: [PATCH] perf scripts python arm-cs-trace-disasm.py: Skip disasm if address continuity is broken
On 08/08/2024 8:42 am, Leo Yan wrote:
On 8/8/2024 5:36 AM, Ganapatrao Kulkarni wrote:
On 08-08-2024 12:50 am, Leo Yan wrote:
On 8/7/2024 5:18 PM, Ganapatrao Kulkarni wrote:
Is below diff with force option looks good?
diff --git a/tools/perf/scripts/python/arm-cs-trace-disasm.py b/tools/perf/scripts/python/arm-cs-trace-disasm.py index d973c2baed1c..efe34f308beb 100755 --- a/tools/perf/scripts/python/arm-cs-trace-disasm.py +++ b/tools/perf/scripts/python/arm-cs-trace-disasm.py @@ -36,7 +36,10 @@ option_list = [ help="Set path to objdump executable file"), make_option("-v", "--verbose", dest="verbose", action="store_true", default=False, - help="Enable debugging log") + help="Enable debugging log"), + make_option("-f", "--force", dest="force", + action="store_true", default=False, + help="Force decoder to continue") ]
parser = OptionParser(option_list=option_list) @@ -257,6 +260,12 @@ def process_event(param_dict): print("Stop address 0x%x is out of range [ 0x%x .. 0x%x ] for dso %s" % (stop_addr, int(dso_start), int(dso_end), dso)) return
+ if (stop_addr < start_addr): + if (options.verbose == True or options.force): + print("Packet Discontinuity detected [stop_add:0x%x start_addr:0x%x ] for dso %s" % (stop_addr, start_addr, dso))
The options.force for the print should be "options.verbose or not options.force" I think? You want to print the error until the user adds -f, then hide it. Unless verbose is on.
+ if (options.force): + return
Oops I had this one the wrong way around in my example. This way is correct.
I struggled a bit for the code - it is confused that force mode bails out and the non-force mode continues to run. I prefer to always bail out for the discontinuity case, as it is pointless to continue in this case.
Kept bail out with force option since I though it is not good to hide the error in normal use, otherwise we never able to notice this error in the future and it becomes default hidden. Eventually this error should be fixed.
As James said, the issue should be fixed in OpenCSD or Perf decoding flow.
Thus, perf tool should be tolerant errors - report warning and drop discontinuous samples. This would be easier for developers later if face the same issue, they don't need to spend time to locate issue and struggle for overriding the error.
If you prefer to use force option, it might be better to give reasoning and *suggestion* in one go, something like:
if (stop_addr < start_addr): print("Packet Discontinuity detected [stop_add:0x%x start_addr:0x%x ] for dso %s" % (stop_addr, start_addr, dso)) print("Use option '-f' following the script for force mode" if (options.force) returnEither way is fine for me. Thanks a lot for taking time on the issue.
Leo
But your diff looks good Ganapat, I think send a patch with Leo's extra help message added and the first force flipped.
On 08/08/2024 10:21 am, James Clark wrote:
On 08/08/2024 8:42 am, Leo Yan wrote:
On 8/8/2024 5:36 AM, Ganapatrao Kulkarni wrote:
On 08-08-2024 12:50 am, Leo Yan wrote:
On 8/7/2024 5:18 PM, Ganapatrao Kulkarni wrote:
Is below diff with force option looks good?
diff --git a/tools/perf/scripts/python/arm-cs-trace-disasm.py b/tools/perf/scripts/python/arm-cs-trace-disasm.py index d973c2baed1c..efe34f308beb 100755 --- a/tools/perf/scripts/python/arm-cs-trace-disasm.py +++ b/tools/perf/scripts/python/arm-cs-trace-disasm.py @@ -36,7 +36,10 @@ option_list = [ help="Set path to objdump executable file"), make_option("-v", "--verbose", dest="verbose", action="store_true", default=False, - help="Enable debugging log") + help="Enable debugging log"), + make_option("-f", "--force", dest="force", + action="store_true", default=False, + help="Force decoder to continue") ]
parser = OptionParser(option_list=option_list) @@ -257,6 +260,12 @@ def process_event(param_dict): print("Stop address 0x%x is out of range [ 0x%x .. 0x%x ] for dso %s" % (stop_addr, int(dso_start), int(dso_end), dso)) return
+ if (stop_addr < start_addr): + if (options.verbose == True or options.force): + print("Packet Discontinuity detected [stop_add:0x%x start_addr:0x%x ] for dso %s" % (stop_addr, start_addr, dso))
The options.force for the print should be "options.verbose or not options.force" I think? You want to print the error until the user adds -f, then hide it. Unless verbose is on.
+ if (options.force): + return
Oops I had this one the wrong way around in my example. This way is correct.
I struggled a bit for the code - it is confused that force mode bails out and the non-force mode continues to run. I prefer to always bail out for the discontinuity case, as it is pointless to continue in this case.
Kept bail out with force option since I though it is not good to hide the error in normal use, otherwise we never able to notice this error in the future and it becomes default hidden. Eventually this error should be fixed.
As James said, the issue should be fixed in OpenCSD or Perf decoding flow.
Thus, perf tool should be tolerant errors - report warning and drop discontinuous samples. This would be easier for developers later if face the same issue, they don't need to spend time to locate issue and struggle for overriding the error.
If you prefer to use force option, it might be better to give reasoning and *suggestion* in one go, something like:
if (stop_addr < start_addr): print("Packet Discontinuity detected [stop_add:0x%x start_addr:0x%x ] for dso %s" % (stop_addr, start_addr, dso)) print("Use option '-f' following the script for force mode" if (options.force) return
Either way is fine for me. Thanks a lot for taking time on the issue.
Leo
But your diff looks good Ganapat, I think send a patch with Leo's extra help message added and the first force flipped.
One other small detail about Leo's suggestion print out. Can you add an instruction of how to keep the warnings as well:
print("Use option '-f' following the script for force mode. Add '-v' \ to continue printing decode warnings.")
-
James Clark