llvm-project.git/lldb/source/Plugins/Process/Linux/IntelPTSingleBufferTrace.cpp, branch main

[lldb] Use StringRef::{starts,ends}_with (NFC)

2023-12-16T22:39:37+00:00

This patch replaces uses of StringRef::{starts,ends}with with
StringRef::{starts,ends}_with for consistency with
std::{string,string_view}::{starts,ends}_with in C++20.

I'm planning to deprecate and eventually remove
StringRef::{starts,ends}with.

[NFC][TargetParser] Replace uses of llvm/Support/Host.h

2023-02-10T09:59:46+00:00

The forwarding header is left in place because of its use in
`polly/lib/External/isl/interface/extract_interface.cc`, but I have
added a GCC warning about the fact it is deprecated, because it is used
in `isl` from where it is included by Polly.

[llvm] Use llvm::bit_floor instead of llvm::PowerOf2Floor (NFC)

2023-01-28T17:06:31+00:00

[trace] Migrate uses of operator<<(raw_ostream &OS, const Optional &O) to std::optional

2022-12-16T19:30:47+00:00

[trace] Change /sys/bus const char * variables to const char []

2022-12-16T08:07:07+00:00

JSON: llvm::Optional => std::optional

2022-12-16T07:56:52+00:00

Many files are from language servers.

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

[lldb] Use llvm::transformOptional (NFC)

2022-12-15T02:36:49+00:00

This is part of an effort to migrate from llvm::Optional to
std::optional:

https://discourse.llvm.org/t/deprecating-llvm-optional-x-hasvalue-getvalue-getvalueor/63716

[lldb] Use Optional::transform instead of Optional::map (NFC)

2022-08-20T04:40:47+00:00

[NFC][lldb][trace] Fix formatting of tracing files

2022-08-11T18:00:26+00:00

Pavel Labath taught me that clang-format sorts headers automatically
using llvm's rules, and it's better not to have spaces between

So in this diff I'm removing those spaces and formatting them as well.

I used `clang-format -i` to format these files.

[trace][intel pt] Add a cgroup filter

2022-07-13T19:26:11+00:00

It turns out that cgroup filtering is relatively trivial and works
really nicely. Thid diffs adds automatic cgroup filtering when in
per-cpu mode, unless a new --disable-cgroup-filtering flag is passed in
the start command. At least on Meta machines, all processes are spawned
inside a cgroup by default, which comes super handy, because per cpu
tracing is now much more precise.

A manual test gave me this result

- Without filtering:
    Total number of trace items: 36083
    Total number of continuous executions found: 229
    Number of continuous executions for this thread: 2
    Total number of PSB blocks found: 98
    Number of PSB blocks for this thread 2
    Total number of unattributed PSB blocks found: 38

- With filtering:
    Total number of trace items: 87756
    Total number of continuous executions found: 123
    Number of continuous executions for this thread: 2
    Total number of PSB blocks found: 10
    Number of PSB blocks for this thread 3
    Total number of unattributed PSB blocks found: 2

Filtering gives us great results. The number of instructions collected
more than double (probalby because we have less noise in the trace), and
we have much less unattributed PSBs blocks and unrelated PSBs in
general. The ones that are unrelated probably belong to other processes
in the same cgroup.

Differential Revision: https://reviews.llvm.org/D129257