Summary:
This addresses http://llvm.org/PR36790.
The change Deprecates a number of functions and types in
`include/xray/xray_log_interface.h` to recommend using string-based
configuration of XRay through the __xray_log_init_mode(...) function. In
particular, this deprecates the following:
- `__xray_set_log_impl(...)` -- users should instead use the
`__xray_log_register_mode(...)` and `__xray_log_select_mode(...)` APIs.
- `__xray_log_init(...)` -- users should instead use the
`__xray_log_init_mode(...)` function, which also requires using the
`__xray_log_register_mode(...)` and `__xray_log_select_mode(...)`
functionality.
- `__xray::FDRLoggingOptions` -- in following patches, we'll be
migrating the FDR logging implementations (and tests) to use the
string-based configuration. In later stages we'll remove the
`__xray::FDRLoggingOptions` type, and ask users to migrate to using the
string-based configuration mechanism instead.
- `__xray::BasicLoggingOptions` -- same as `__xray::FDRLoggingOptions`,
we'll be removing this type later and instead rely exclusively on the
string-based configuration API.
We also update the documentation to reflect the new advice and remove
some of the deprecated notes.
Reviewers: eizan, kpw, echristo, pelikan
Reviewed By: kpw
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D46173
llvm-svn: 331503
Summary:
This change adds APIs to allow logging implementations to provide a
function for iterating through in-memory buffers (if they hold in-memory
buffers) and a way for users to generically deal with these buffers
in-process. These APIs are:
- __xray_log_set_buffer_iterator(...) and
__xray_log_remove_buffer_iterator(): installs and removes an
iterator function that takes an XRayBuffer and yields the next one.
- __xray_log_process_buffers(...): takes a function pointer that can
take a mode identifier (string) and an XRayBuffer to process this
data as they see fit.
The intent is to have the FDR mode implementation's buffers be
available through this `__xray_log_process_buffers(...)` API, so that
they can be streamed from memory instead of flushed to disk (useful for
getting the data to a network, or doing in-process analysis).
Basic mode logging will not support this mechanism as it's designed to
write the data mostly to disk.
Future implementations will may depend on this API as well, to allow for
programmatically working through the XRay buffers exposed to the
users in some fashion.
Reviewers: eizan, kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D43495
llvm-svn: 326866
Summary:
This change allows for registration of multiple logging implementations
through a central mechanism in XRay, mapping an implementation to a
"mode". Modes are strings that are used as keys to determine which
implementation to install through a single API. This mechanism allows
users to choose which implementation to install either from the
environment variable 'XRAY_OPTIONS' with the `xray_mode=` flag, or
programmatically using the `__xray_select_mode(...)` function.
Here, we introduce two API functions for the XRay logging:
__xray_log_register_mode(Mode, Impl): Associates an XRayLogImpl to a
string Mode. We can only have one implementation associated with a given
Mode.
__xray_log_select_mode(Mode): Finds the associated Impl for Mode and
installs it as if by calling `__xray_set_log_impl(...)`.
Along with these changes, we also deprecate the xray_naive_log and
xray_fdr_log flags and encourage users to instead use the xray_mode
flag.
Reviewers: kpw, dblaikie, eizan, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D40703
llvm-svn: 319759
Summary:
Remove dependency on std::unique_ptr<...> for the global representing
the installed XRay implementation.
Reviewers: dblaikie, kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D38121
llvm-svn: 313871
Summary:
In this patch we document the requirements for implementations that want
to install handlers for the dynamically-controlled XRay "framework".
This clarifies what the expectations are for implementations that
want to install their handlers using this API (similar to how the FDR
logging implementation does so). It also gives users some guarantees on
semantics for the APIs.
If all goes well, users can decide to use the XRay APIs to control the
tracing/logging at the application level, without having to depend on
implementation details of the installed logging implementation. This
lets users choose the implementation that comes with compiler-rt, or
potentially multiple other implementations that use the same APIs.
We also add one convenience function (__xray_remove_log_impl()) for
explicitly removing the currently installed log implementation.
Reviewers: kpw, pelikan
Subscribers: llvm-commits
Differential Revision: https://reviews.llvm.org/D32579
llvm-svn: 301784
Summary:
This change exercises the end-to-end functionality defined in the FDR
logging implementation. We also prepare for being able to run traces
generated by the FDR logging implementation from being analysed with the
llvm-xray command that comes with the LLVM distribution.
This also unblocks D31385, D31384, and D31345.
Reviewers: kpw, pelikan
Subscribers: llvm-commits, mgorny
Differential Revision: https://reviews.llvm.org/D31452
llvm-svn: 298977
Instead of std::atomic APIs for atomic operations, we instead use APIs
include with sanitizer_common. This allows us to, at runtime, not have
to depend on potentially dynamically provided implementations of these
atomic operations.
Fixes http://llvm.org/PR32274.
llvm-svn: 298833
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
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
Dean Michael Berris