[Lldb-commits] [PATCH] D45547: [Command] Implement `stats`
Jim Ingham via Phabricator via lldb-commits
lldb-commits at lists.llvm.org
Thu Apr 12 14:38:40 PDT 2018
jingham added a comment.
Timers seemed like they would be really useful for collection of data about operations in lldb, but for most things I think they end up being hard to use because actual wall-clock time is so variable from run to run, and especially for disk and inter-process heavy operations, which lldb tends to be. I'm not sure we should give up on timers, sometimes you want to know "how many times did I do X" and other times "how long did X take" and the Timers are more useful for this than just a sample or wall-clock times because you can find out how long it took "in the Dwarf parser", etc.
But in many cases our performance is more driven by unnecessary lookups, and that sort of error. For that sort of error it will be much more useful to say "given program A and expression B, how many DWARF DIE lookups did I do" than "how long did I spent wall-clock in the DWARF parser..." When the former goes from 20 to 2000, that will be a much clearer symbol that we probably introduced a performance regression.
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