On Sat, 8 Feb 2025 06:56:40 GMT, Thomas Stuefe <stu...@openjdk.org> wrote:
> Greetings, > > This is a rewrite of the Compiler Memory Statistic. The primary new feature > is the capability to track allocations by C2 phases. This will allow for a > much faster, more thorough analysis of footprint issues. > > Tracking Arena memory movement is not trivial since one needs to follow the > ebb and flow of allocations over nested C2 phases. A phase typically > allocates more than it releases, accruing new nodes and resource area. A > phase can also release more than allocated when Arenas carried over from > other phases go out of scope in this phase. Finally, it can have high > temporary peaks that vanish before the phase ends. > > I wanted to track that information correctly and display it clearly in a way > that is easy to understand. > > The patch implements per-phase tracking by instrumenting the `TracePhase` > stack object (thanks to @rwestrel for this idea). > > The nice thing with this technique is that it also allows for quick analysis > of a suspected hot spot (eg, the inside of a loop): drop a TracePhase in > there with a speaking name, and you can see the allocations inside that phase. > > The statistic gives us two new forms of output: > > 1) At the moment the compilation memory *peaked*, we now get a detailed > breakdown of that peak usage per phase: > > > Arena Usage by Arena Type and compilation phase, at arena usage peak of > 58817816: > Phase Total ra node comp > type index reglive regsplit cienv other > none 1205512 155104 982984 33712 > 0 0 0 0 0 33712 > parse 11685376 720016 6578728 1899064 > 0 0 0 0 1832888 654680 > optimizer 916584 0 556416 0 > 0 0 0 0 0 360168 > escapeAnalysis 1983400 0 1276392 707008 > 0 0 0 0 0 0 > connectionGraph 720016 0 0 621832 > 0 0 0 0 98184 0 > macroEliminate 196448 0 196448 0 > 0 0 0 0 0 0 > iterGVN 327440 0 196368 131072 > 0 0 0 0 0 0 > incrementalInline 3992816 0 3043704 621832 > 0 0 0 0 261824... src/hotspot/share/runtime/handles.hpp line 2: > 1: /* > 2: * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All rights > reserved. Nit: unnecessary copyright header change. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/23530#discussion_r1955794509
