Commit Graph

4 Commits

Author SHA1 Message Date
Chandler Carruth 2946cd7010 Update the file headers across all of the LLVM projects in the monorepo
to reflect the new license.

We understand that people may be surprised that we're moving the header
entirely to discuss the new license. We checked this carefully with the
Foundation's lawyer and we believe this is the correct approach.

Essentially, all code in the project is now made available by the LLVM
project under our new license, so you will see that the license headers
include that license only. Some of our contributors have contributed
code under our old license, and accordingly, we have retained a copy of
our old license notice in the top-level files in each project and
repository.

llvm-svn: 351636
2019-01-19 08:50:56 +00:00
Dean Michael Berris 25d505953a [XRay] Use preallocated memory for XRay profiling
Summary:
This change builds upon D54989, which removes memory allocation from the
critical path of the profiling implementation. This also changes the API
for the profile collection service, to take ownership of the memory and
associated data structures per-thread.

The consolidation of the memory allocation allows us to do two things:

- Limits the amount of memory used by the profiling implementation,
  associating preallocated buffers instead of allocating memory
  on-demand.

- Consolidate the memory initialisation and cleanup by relying on the
  buffer queue's reference counting implementation.

We find a number of places which also display some problematic
behaviour, including:

- Off-by-factor bug in the allocator implementation.

- Unrolling semantics in cases of "memory exhausted" situations, when
  managing the state of the function call trie.

We also add a few test cases which verify our understanding of the
behaviour of the system, with important edge-cases (especially for
memory-exhausted cases) in the segmented array and profile collector
unit tests.

Depends on D54989.

Reviewers: mboerger

Subscribers: dschuff, mgorny, dmgreen, jfb, llvm-commits

Differential Revision: https://reviews.llvm.org/D55249

llvm-svn: 348568
2018-12-07 06:23:06 +00:00
Dean Michael Berris ca856e07de [XRay] Fixup: Address some warnings breaking build
Follow-up to D45758.

llvm-svn: 333625
2018-05-31 04:55:11 +00:00
Dean Michael Berris 1eb8c206cd [XRay][profiler] Part 3: Profile Collector Service
Summary:
This is part of the larger XRay Profiling Mode effort.

This patch implements a centralised collector for `FunctionCallTrie`
instances, associated per thread. It maintains a global set of trie
instances which can be retrieved through the XRay API for processing
in-memory buffers (when registered). Future changes will include the
wiring to implement the actual profiling mode implementation.

This central service provides the following functionality:

*  Posting a `FunctionCallTrie` associated with a thread, to the central
   list of tries.

*  Serializing all the posted `FunctionCallTrie` instances into
   in-memory buffers.

*  Resetting the global state of the serialized buffers and tries.

Depends on D45757.

Reviewers: echristo, pelikan, kpw

Reviewed By: kpw

Subscribers: llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D45758

llvm-svn: 333624
2018-05-31 04:33:52 +00:00