Re: [PATCH v7 bpf-next 0/3] bpf: introduce bpf_get_branch_snapshot

From: Alexei Starovoitov
Date: Mon Sep 13 2021 - 14:00:10 EST


On Fri, Sep 10, 2021 at 11:34 AM Song Liu <songliubraving@xxxxxx> wrote:
>
> Changes v6 => v7:
> 1. Improve/fix intel_pmu_snapshot_branch_stack() logic. (Peter).
>
> Branch stack can be very useful in understanding software events. For
> example, when a long function, e.g. sys_perf_event_open, returns an errno,
> it is not obvious why the function failed. Branch stack could provide very
> helpful information in this type of scenarios.
>
> This set adds support to read branch stack with a new BPF helper
> bpf_get_branch_trace(). Currently, this is only supported in Intel systems.
> It is also possible to support the same feaure for PowerPC.

Applied. Thanks