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Being able to ‘connect’ call stacks between python, c++, and the gpu/accelerator seems useful. I wonder if this pushes a bit much towards flamegraphs specifica
by dan-robertson 2y ago
Being able to ‘connect’ call stacks between python, c++, and the gpu/accelerator seems useful.
I wonder if this pushes a bit much towards flamegraphs specifically. They were an innovation when they were first invented and the alternatives were things like perf report, but now I think they’re more one tool among many. In particular, I think many people who are serious about performance often reach for things like pprof for statistical profiles and various traceing and trace-visualisation tools for more fine-grained information (things like bpftrace, systemtap, or custom instrumentation on the recording side and perfetto or the many game-development oriented tools on the visualisation (and sometimes instrumentation) side).
I was particularly surprised by the statement about intel’s engineers not knowing what to do with the flamegraphs. I read it as them already having tools that are better suited to their particular needs, because I think the alternative has to be that they are incompetent or, at best, not thinking about performance at all.
Lots of performance measuring on Linux is done through the perf subsystem and Intel have made a lot of contributions to make it good. Similarly, Intel have added hardware features that are useful for measuring and improving performance – an area where their chips have features that, at least on chips I’ve used, easily beat AMD’s offerings. This kind of plumbing is important and useful, and I guess the flamegraphs demonstrate that the plumbing was done.
- stefan_ 2y agoIt's a bit weird, very much a "software optimization" approach. But looking at the flame graph, you couldn't tell a model running in FP32 from one in INT8, taking 3x the time and energy.
- bornfreddy 2y agoAnd? This is an information trivially obtainable in a different way (e.g. using a stopwatch), while flamegraphs visualise where that time was spent, helping us to determine the parts that need to be optimised.
- deleted 2y ago[deleted]