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1 //===-- xray_profile_collector.h -------------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // This file is a part of XRay, a dynamic runtime instrumentation system.
10 //
11 // This file defines the interface for a data collection service, for XRay
12 // profiling. What we implement here is an in-process service where
13 // FunctionCallTrie instances can be handed off by threads, to be
14 // consolidated/collected.
15 //
16 //===----------------------------------------------------------------------===//
17 #ifndef XRAY_XRAY_PROFILE_COLLECTOR_H
18 #define XRAY_XRAY_PROFILE_COLLECTOR_H
19 
20 #include "xray_function_call_trie.h"
21 
22 #include "xray/xray_log_interface.h"
23 
24 namespace __xray {
25 
26 /// The ProfileCollectorService implements a centralised mechanism for
27 /// collecting FunctionCallTrie instances, indexed by thread ID. On demand, the
28 /// ProfileCollectorService can be queried for the most recent state of the
29 /// data, in a form that allows traversal.
30 namespace profileCollectorService {
31 
32 /// Posts the FunctionCallTrie associated with a specific Thread ID. This
33 /// will:
34 ///
35 /// Moves the collection of FunctionCallTrie, Allocators, and Buffers associated
36 /// with a thread's data to the queue. This takes ownership of the memory
37 /// associated with a thread, and manages those exclusively.
38 ///
39 void post(BufferQueue *Q, FunctionCallTrie &&T,
40           FunctionCallTrie::Allocators &&A,
41           FunctionCallTrie::Allocators::Buffers &&B, tid_t TId);
42 
43 /// The serialize will process all FunctionCallTrie instances in memory, and
44 /// turn those into specifically formatted blocks, each describing the
45 /// function call trie's contents in a compact form. In memory, this looks
46 /// like the following layout:
47 ///
48 ///   - block size (32 bits)
49 ///   - block number (32 bits)
50 ///   - thread id (64 bits)
51 ///   - list of records:
52 ///     - function ids in leaf to root order, terminated by
53 ///       0 (32 bits per function id)
54 ///     - call count (64 bit)
55 ///     - cumulative local time (64 bit)
56 ///     - record delimiter (64 bit, 0x0)
57 ///
58 void serialize();
59 
60 /// The reset function will clear out any internal memory held by the
61 /// service. The intent is to have the resetting be done in calls to the
62 /// initialization routine, or explicitly through the flush log API.
63 void reset();
64 
65 /// This nextBuffer function is meant to implement the iterator functionality,
66 /// provided in the XRay API.
67 XRayBuffer nextBuffer(XRayBuffer B);
68 
69 } // namespace profileCollectorService
70 
71 } // namespace __xray
72 
73 #endif // XRAY_XRAY_PROFILE_COLLECTOR_H
74