[llvm-dev] RFC: Sanitizer-based Heap Profiler

[Andrey Bokhanko via llvm-dev]

Sorry if I sounded too demanding: the easiest thing in the World to do
is to sit on a sofa and throw one demand after another... :-)

I understand that you have a big field full of question marks in front
of you and an immensely challenging task. My "tsk, tsk" message was
said with a tongue in cheek.

On Thu, Jul 8, 2021 at 7:04 PM Teresa Johnson <tejohnson at google.com> wrote:
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> On Thu, Jul 8, 2021 at 8:56 AM Andrey Bokhanko <andreybokhanko at gmail.com> wrote:
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>> On Thu, Jul 8, 2021 at 6:25 PM Teresa Johnson <tejohnson at google.com> wrote:
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>>> Responding to this one first, I'll respond to your other email shortly. Initially we plan to provide hints to tcmalloc via new APIs to help it make allocation decisions (things like hotness and lifetime). The compiler will be responsible for adding these hints, using some method to disambiguate the calling context (e.g. via function cloning, new parameter, etc).
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>> Sounds good -- thanks!
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>> (though this would increase code size and thus, instruction cache pressure -- tsk, tsk... :-))
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> There are various methods for disambiguating the contexts (e.g. HALO inserts some instructions at a minimal number of callsites to do this), and I suspect a hybrid method will be best in practice. E.g. cloning for hot allocation contexts or callsites, and instructions or parameters or something else on colder allocation contexts and callsites, to balance the code size and dynamic instruction overheads.
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> Teresa Johnson | Software Engineer | tejohnson at google.com |