Commit Graph

8 Commits

Author SHA1 Message Date
Dean Michael Berris c84c46fc0c [XRay] Add LD_LIBRARY_PATH to env variables for Unit Tests
Summary:
This change allows us to use the library path from which the LLVM
libraries are installed, in case the LLVM installation generates shared
libraries.

This should address llvm.org/PR39070.

Reviewers: mboerger, eizan

Subscribers: mgorny, jfb, llvm-commits

Differential Revision: https://reviews.llvm.org/D52597

llvm-svn: 343280
2018-09-27 23:15:05 +00:00
Dean Michael Berris 1704f6289a [XRay][compiler-rt] Enable the XRay compiler-rt unit tests.
Summary:
Before this change we seemed to not be running the unit tests, and therefore we
set out to run them. In the process of making this happen we found a divergence
between the implementation and the tests.

This includes changes to both the CMake files as well as the implementation and
headers of the XRay runtime. We've also updated documentation on the changed
functions.

Reviewers: kpw, eizan

Subscribers: mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D37290

llvm-svn: 312202
2017-08-31 00:50:12 +00:00
Dean Michael Berris e7dbebf182 [XRay][compiler-rt] XRay Flight Data Recorder Mode
Summary:
In this change we introduce the notion of a "flight data recorder" mode
for XRay logging, where XRay logs in-memory first, and write out data
on-demand as required (as opposed to the naive implementation that keeps
logging while tracing is "on"). This depends on D26232 where we
implement the core data structure for holding the buffers that threads
will be using to write out records of operation.

This implementation only currently works on x86_64 and depends heavily
on the TSC math to write out smaller records to the inmemory buffers.

Also, this implementation defines two different kinds of records with
different sizes (compared to the current naive implementation): a
MetadataRecord (16 bytes) and a FunctionRecord (8 bytes). MetadataRecord
entries are meant to write out information like the thread ID for which
the metadata record is defined for, whether the execution of a thread
moved to a different CPU, etc. while a FunctionRecord represents the
different kinds of function call entry/exit records we might encounter
in the course of a thread's execution along with a delta from the last
time the logging handler was called.

While this implementation is not exactly what is described in the
original XRay whitepaper, this one gives us an initial implementation
that we can iterate and build upon.

Reviewers: echristo, rSerge, majnemer

Subscribers: mehdi_amini, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D27038

llvm-svn: 293015
2017-01-25 03:50:46 +00:00
Dean Michael Berris 0aba35710f Revert "[XRay][compiler-rt] XRay Flight Data Recorder Mode"
This reverts rL290852 as it breaks aarch64 and arm.

llvm-svn: 290854
2017-01-03 04:04:00 +00:00
Dean Michael Berris 33d305b54b [XRay][compiler-rt] XRay Flight Data Recorder Mode
Summary:
In this change we introduce the notion of a "flight data recorder" mode
for XRay logging, where XRay logs in-memory first, and write out data
on-demand as required (as opposed to the naive implementation that keeps
logging while tracing is "on"). This depends on D26232 where we
implement the core data structure for holding the buffers that threads
will be using to write out records of operation.

This implementation only currently works on x86_64 and depends heavily
on the TSC math to write out smaller records to the inmemory buffers.

Also, this implementation defines two different kinds of records with
different sizes (compared to the current naive implementation): a
MetadataRecord (16 bytes) and a FunctionRecord (8 bytes). MetadataRecord
entries are meant to write out information like the thread ID for which
the metadata record is defined for, whether the execution of a thread
moved to a different CPU, etc. while a FunctionRecord represents the
different kinds of function call entry/exit records we might encounter
in the course of a thread's execution along with a delta from the last
time the logging handler was called.

While this implementation is not exactly what is described in the
original XRay whitepaper, this one gives us an initial implementation
that we can iterate and build upon.

Reviewers: echristo, rSerge, majnemer

Subscribers: mehdi_amini, llvm-commits, mgorny

Differential Revision: https://reviews.llvm.org/D27038

llvm-svn: 290852
2017-01-03 03:38:17 +00:00
Dean Michael Berris abe04e3295 [XRay][compiler-rt] XRay Buffer Queue
This implements a simple buffer queue to manage a pre-allocated queue of
fixed-sized buffers to hold XRay records. We need this to support
Flight Data Recorder (FDR) mode. We also implement this as a sub-library
first to allow for development before actually using it in an
implementation.

Some important properties of the buffer queue:

- Thread-safe enqueueing/dequeueing of fixed-size buffers.
- Pre-allocation of buffers at construction.

This is a re-roll of the previous attempt to submit, because it caused
failures in arm and aarch64.

Reviewers: majnemer, echristo, rSerge

Subscribers: tberghammer, danalbert, srhines, modocache, mehdi_amini, mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D26232

llvm-svn: 288775
2016-12-06 06:24:08 +00:00
Dean Michael Berris 291d74bdb4 Revert "[XRay][compiler-rt] XRay Buffer Queue"
Broke the build on arm7 and aarch64.

llvm-svn: 287911
2016-11-25 03:54:45 +00:00
Dean Michael Berris 47119579c8 [XRay][compiler-rt] XRay Buffer Queue
Summary:
This implements a simple buffer queue to manage a pre-allocated queue of
fixed-sized buffers to hold XRay records. We need this to support
Flight Data Recorder (FDR) mode. We also implement this as a sub-library
first to allow for development before actually using it in an
implementation.

Some important properties of the buffer queue:

- Thread-safe enqueueing/dequeueing of fixed-size buffers.
- Pre-allocation of buffers at construction.

Reviewers: majnemer, rSerge, echristo

Subscribers: mehdi_amini, mgorny, llvm-commits

Differential Revision: https://reviews.llvm.org/D26232

llvm-svn: 287910
2016-11-25 03:14:10 +00:00