[Profiler] Optimize `reportMemoryUsage` (#71538)
Summary:
Pull Request resolved: https://github.com/pytorch/pytorch/pull/71538
`reportMemoryUsage` is kind of awful. It does a bunch of string writes and such that makes it VERY expensive. Just moving that work off the hot path reduces the overhead for `profile_memory` from ~6.5 us to ~1.2 us. (85% reduction in the kineto contribution to profiling overhead.)
Test Plan: Ran ubenchmark with `--op empty --stressTestKineto --kinetoProfileMemory`
Reviewed By: swolchok
Differential Revision: D32730167
fbshipit-source-id: fe18e8fa3881967cad8fa1c26c71c805e9b034e5
(cherry picked from commit 0d394cb252e6eac78626b467e0bb497d6d6ae86c)
