Siva Annamalai
74c5aa3a7a
This reverts commitf81a402aa1. Reason for revert: golem benchmarks are failing to run TEST=ci Original change's description: > "[SDK/VM] - Rename dart_precompiled_runtime to dartaotruntime, ensures we have a uniform name for the executable between the build directories and the SDK directory" > > Fixed golem breakage by temporarily copying dartaotruntime to dart_precompiled_runtime > > This reverts commit75e6a748f7. > > TEST=ci > > Original change's description: > > Revert "[SDK/VM] - Rename dart_precompiled_runtime to dartaotruntime, ensures we have a uniform name for the executable between the build directories and the SDK directory" > > > > This reverts commit1b331d05c2. > > > > Reason for revert: golem builds are failing > > > > Original change's description: > > > [SDK/VM] - Rename dart_precompiled_runtime to dartaotruntime, ensures we have a uniform name for the executable between the build directories and the SDK directory > > > > > > TEST=ci > > > > > Change-Id: Id0f383eabb496c06c0acebc639c8e3b056ba82d0 > Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/393781 > Commit-Queue: Siva Annamalai <asiva@google.com> > Reviewed-by: Ryan Macnak <rmacnak@google.com> Change-Id: Iec494940412aa31dbefdc5280e35ae99e8cecb26 No-Presubmit: true No-Tree-Checks: true No-Try: true Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/393764 Reviewed-by: Siva Annamalai <asiva@google.com> Reviewed-by: Liam Appelbe <liama@google.com> Bot-Commit: Rubber Stamper <rubber-stamper@appspot.gserviceaccount.com> Commit-Queue: Siva Annamalai <asiva@google.com>
Various tools for low level profing of code running on the Dart VM.
Uprobe based profiling
uprobes is
a user-space dynamic tracing mechanism. Using this mechanism the kernel can
be instructed to place a tracepoint at a particular file offset within a
specific binary. Whenever this tracepoint is hit the kernel will fetch values
from the execution context based on the uprobe's description and emit an event.
A developer can subscribe to uprobe events in a few different ways including
perf_event_open
syscall. uprobes have been enabled by default on all newish Linux kernels
(4.14+), however they are only truly usable on Android/ARM64 starting from
5.10+. bin/set_uprobe.dart is a helper script for placing uprobes inside
binaries and using this for profiling.
The core workflow looks like this:
$ sudo $(which dart) runtime/tools/profiling/bin/set_uprobe.dart probeName symbol binary
This will create an uprobe with name probeName which triggers whenever
the given symbol inside the given binary is called. You can then record
an event (and collect the call stack) using:
$ sudo perf record -g -e uprobes:probeName ...
Allocation profiling with uprobes
AOT compiler can emit a special probe point (stub AllocationProbePoint) which
triggers for each new space allocation from generated code. set_uprobe script
has special support for this probe point: it will configure probe point to
record additional information (address of allocated object, allocation top and
cid of the allocated object) allowing to post process collected data into
an actual allocation profile.
Start by compiling your application with --generate-probe-points:
$ pkg/vm/tool/precompiler2 --generate-probe-points test.dart test.aot
Then install uprobe on AllocationProbePoint:
$ sudo $(which dart) runtime/tools/profiling/bin/set_uprobe.dart alloc AllocationProbePoint test.aot
Record the profile:
$ sudo perf record -g -e uprobes:alloc out/ReleaseX64/dart_precompiled_runtime test.aot
$ sudo chmod 0755 perf.data
Produce a coalesced allocation profile from the recording:
$ dart runtime/tools/profiling/bin/convert_allocation_profile.dart perf.data
$ pprof -flame pprof.profile