Reenable method tracing safely [316174880]

Fixed

Bug

Status Update

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Description

cc...@google.com

created issue #1

Dec 13, 2023 07:03PM

After turning method tracing on in microbench by default in all cases, we have over time found multiple issues where runtime performance is drastically reduced after capturing a method trace, depending on OS version and ART mainline version.

API 34 or certain mainline releases: Method tracing disables AOT compilation, observable JIT. b/303660864
API 26-30: Method tracing regresses performance, but without observable JIT. b/313868903
API 21: Method tracing corrupts stack. b/300658578

We also found that it was necessary to suppress method traces on long running benchmarks to avoid ANRs, as even a single loop of a compose benchmark can take several seconds to trace. This made numbers and tracing behavior both less predictable, because duration of benchmark now defines whether it gets a method trace, since it's used to predict if simply taking a method trace on the UI thread will cause an ANR. See b/311412125

Currently, method tracing is off by default, everywhere, we want to turn it back on safely.

Tasks:

Enable method tracing by default only on certain OS and ART mainline versions
Add a warning when method tracing can't be enabled safely, with suggestion of what to do
Throw rather than capture invalid data (similar to the old startup microbench mode)

Comments

cc...@google.com <cc...@google.com> #2Dec 19, 2023 07:49PM

Based on the ASM changelog: https://asm.ow2.io/versions.html

ASM 8.0 add support for Java 14.

So seems that all we would need to do is to upgrade ASM dependency. AFAIK the ASM version in jetifier needs to be in sync with what AGP / AS is using. Can you Hung confirm if we could make the upgrade happen?

cc...@google.com <cc...@google.com> #3Dec 19, 2023 07:53PM

Marked as fixed.

Ah yes, this will likely be solved once we upgrade AGP to use ASM 8.

@#1: As a workaround, you can add the following to your root build.gradle file to upgrade the tools to ASM 8:

buildscript {
    repositories {
        ...
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:4.0.0'
        classpath 'org.ow2.asm:asm:8.0'
        classpath 'org.ow2.asm:asm-util:8.0'
        classpath 'org.ow2.asm:asm-commons:8.0'
    }
}

Issue 316174880

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Comments

cc...@google.com <cc...@google.com> #2Dec 19, 2023 07:49PM

cc...@google.com <cc...@google.com> #3Dec 19, 2023 07:53PM

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