There are a number of things that can appear in memory report process names and paths that break diffs. These are in two categories. * Non-deterministic IDs: + Addresses + PIDs + null principal UUIDs - Window IDs, e.g. |top("http://foo.com/", id=8)| * Counts: - String copy counts, e.g. |string(length=131878, copies=1, "...")| - Script source reference counts, e.g. |source(scripts=1501, <non-notable files>)| - (Potential) Object and shape instance counts e.g. |class(Array, nobjs=43)| The ones marked with '+' are currently handled (i.e. stripped) in about:memory via regexps. It would be nice if we had a consistent way of handling these, instead of adding them in an ad hoc fashion when we realize they are necessary (e.g. bug 1054318, bug 1005442, bug 1056954). I don't have a particular idea in mind of how to do this, though.
With this any number that needs to be sanitized in a diff can be surrounded by some special chars, and about:memory will deal with it appropriately. E.g. "^^^^" becomes "12345" normally, and "NNN" in a diff. Pros: - It works. - It moves the "does this number need special treatment" logic from about:memory (or other memory report consumer) to the memory reporter. Cons: - The syntax is ugly -- I had to choose something that was very unlikely to match anything in a path. And since paths can contain arbitrary strings, which can contain URLs and JS/CSS/HTML code, I had to choose something weird. '^' is notable for being one of the few symbols that doesn't come up in practice in paths. (Backtick is another... maybe ``123`` would be better syntax.) - AWSY will need updating. - Similarly, if you're using an older Firefox, and you load memory reports generated by a newer Firefox, you'll get lots of batwings in the output. I'm not totally convinced by this patch, but I don't see how else to do it. Suggestions are welcome.
Assignee: nobody → n.nethercote
Status: NEW → ASSIGNED
erahm and I discusses this on IRC, and concluded that: - it's pretty ugly; - more ad hoc filtering in about:memory is probably the least worst thing to do for now; and - at some point there should be a big overhaul of memory reporting that can address this problem properly.
Status: ASSIGNED → RESOLVED
Last Resolved: 5 years ago
Resolution: --- → WONTFIX
Let's recycle this bug. This patch does the following: - Adds more comments about the stripping. - Make the address stripping less promiscuous. - Adds top window ID stripping. I decided that counts shouldn't be stripped. Even if we hit a case where it's relevant (i.e. the memory size is the same but the counts are different) that seems worth distinguishing.
Attachment #8491252 - Flags: review?(erahm)
Comment on attachment 8491252 [details] [diff] [review] Filter diff-breaking info from memory reports in a more rigorous fashion Review of attachment 8491252 [details] [diff] [review]: ----------------------------------------------------------------- lgtm
Attachment #8491252 - Flags: review?(erahm) → review+
Try looks good: https://tbpl.mozilla.org/?tree=Try&rev=5b2b08df68f0. The Mulet bustage appears to be bug 1069702, and not my fault.
Status: RESOLVED → REOPENED
Resolution: WONTFIX → ---
Status: REOPENED → RESOLVED
Last Resolved: 5 years ago → 5 years ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla35
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