0002184: Distinguish distinct calls to same function in cachegrind.out file - MantisBT

ID	Project	Category	View Status	Date Submitted	Last Update

0002184	Xdebug	Profiling	public	2023-06-29 18:03	2023-07-04 16:09

Reporter	donquixote	Assigned To	derick
Priority	normal	Severity	minor	Reproducibility	have not tried
Status	resolved	Resolution	won't fix
Product Version	3.2.1

Summary	0002184: Distinguish distinct calls to same function in cachegrind.out file
Description	When viewing profiling data with KCachegrind, I would like to be able to distinguish distinct calls to the same function, if they have a distinct stack trace. I was wondering if this is even possible with the data recorded in a cachegrind.out.* file, but it seems it is not! I tried to understand the output of a cachegrind.out.* file and found this: https://valgrind.org/docs/manual/cl-format.html Not exactly about xdebug but I think most of what is written there also applies here. The references from one call to another are like "cfl=(123)" or "cfn=(456)", which references file names and function names, but not individual calls. Due to this, there is always ambiguity in the call tree. It would be cool if: xdebug would have an option to add info into the cachegrind.out.* file that references other calls instead of just functions. Later, KCachegrind or other tools could use this information to show a complete call tree.
Additional Information	Interestingly, in the past I used wincachegrind, which seemed to have this functionality. But I don't know how it extracted that information from a cachegrind.out.* file, which does not really have it.
Tags	profiling

Operating System	Ubuntu
PHP Version	8.2.0-8.2.9

donquixote 2023-06-29 19:33 reporter ~0006572	Actually... can the order of entries be used to resolve ambiguities? In that case, I could use a script to process and disambiguate, e.g. by appending something to the function names. And KCachegrind would have the same option.

derick 2023-07-04 16:09 administrator ~0006577	Hi, Xdebug's profiler generates the same file format that KCacheGrind/QKcacheGrind expect. I can't just change that as that will break tools that expect these formats. Although I don't quite understand what you're trying to do here, but if you want a full callgraph, where you can see the structure of calls, which calls what, what arguments and return values are, Xdebug has a "tracer" (https://xdebug.org/docs/trace) which should do exactly all of that. There is a specific format that dumps it in a TSV file, for which you can fairly easily write tools to analyses. The Xdebug source distribution even includes such a script (https://github.com/xdebug/xdebug/blob/master/contrib/tracefile-analyser.php). I hope that helps! cheers, Derick

Date Modified	Username	Field	Change
2023-06-29 18:03	donquixote	New Issue
2023-06-29 18:03	donquixote	Tag Attached: profiling
2023-06-29 19:33	donquixote	Note Added: 0006572
2023-07-04 16:09	derick	Assigned To	=> derick
2023-07-04 16:09	derick	Status	new => resolved
2023-07-04 16:09	derick	Resolution	open => won't fix
2023-07-04 16:09	derick	Note Added: 0006577