[PATCH] D107876: [CSSPGO] Allow the use of debug-info-for-profiling and pseudo-probe-for-profiling together

Wed Aug 11 22:48:20 PDT 2021

wmi accepted this revision.
wmi added a comment.

In D107876#2939691 <https://reviews.llvm.org/D107876#2939691>, @hoy wrote:

> In D107876#2939624 <https://reviews.llvm.org/D107876#2939624>, @wmi wrote:
>
>> Could you remind me the discriminator difference between debug info based AFDO and pseudo probe based AFDO? I forgot it. I am sure it is described in some patch but I havn't found it. Give me a pointer is good enough.
>
> In short, unlike block pseudo probe, a callsite probe relies on the calliste discriminator to be tracked. This has a couple usage: 1. to track direct call and indirect callsite 2. to model inline contexts with a list of callsite probes.
>
> A probe discriminator is treated as empty or null for AutoFDO since it has lowest three bits as "111".

Thanks for the explanation.

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https://reviews.llvm.org/D107876