Primiano Tucci | d7b59c4 | 2017-12-19 01:43:07 +0100 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2017 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | #include "src/tracing/core/trace_writer_impl.h" |
| 18 | |
| 19 | #include <string.h> |
| 20 | |
| 21 | #include <type_traits> |
| 22 | #include <utility> |
| 23 | |
| 24 | #include "perfetto/base/logging.h" |
| 25 | #include "perfetto/protozero/proto_utils.h" |
Oystein Eftevaag | 6d0bc7f | 2018-01-13 12:21:55 -0800 | [diff] [blame^] | 26 | #include "src/tracing/core/shared_memory_arbiter_impl.h" |
Primiano Tucci | d7b59c4 | 2017-12-19 01:43:07 +0100 | [diff] [blame] | 27 | |
| 28 | #include "protos/trace_packet.pbzero.h" |
| 29 | |
| 30 | // TODO(primiano): right now this class is accumulating a patchlist but not |
| 31 | // sending it to the service. |
| 32 | |
| 33 | using protozero::proto_utils::kMessageLengthFieldSize; |
| 34 | using protozero::proto_utils::WriteRedundantVarInt; |
| 35 | using ChunkHeader = perfetto::SharedMemoryABI::ChunkHeader; |
| 36 | |
| 37 | namespace perfetto { |
| 38 | |
| 39 | namespace { |
| 40 | constexpr size_t kPacketHeaderSize = SharedMemoryABI::kPacketHeaderSize; |
| 41 | } // namespace |
| 42 | |
Oystein Eftevaag | 6d0bc7f | 2018-01-13 12:21:55 -0800 | [diff] [blame^] | 43 | TraceWriterImpl::TraceWriterImpl(SharedMemoryArbiterImpl* shmem_arbiter, |
Primiano Tucci | d7b59c4 | 2017-12-19 01:43:07 +0100 | [diff] [blame] | 44 | WriterID id, |
| 45 | BufferID target_buffer) |
| 46 | : shmem_arbiter_(shmem_arbiter), |
| 47 | id_(id), |
| 48 | target_buffer_(target_buffer), |
| 49 | protobuf_stream_writer_(this) { |
| 50 | // TODO(primiano): we could handle the case of running out of TraceWriterID(s) |
| 51 | // more gracefully and always return a no-op TracePacket in NewTracePacket(). |
| 52 | PERFETTO_CHECK(id_ != 0); |
| 53 | |
| 54 | cur_packet_.reset(new protos::pbzero::TracePacket()); |
| 55 | cur_packet_->Finalize(); // To avoid the DCHECK in NewTracePacket(). |
| 56 | } |
| 57 | |
| 58 | TraceWriterImpl::~TraceWriterImpl() { |
| 59 | // TODO(primiano): this should also return the current chunk. Add tests. |
| 60 | shmem_arbiter_->ReleaseWriterID(id_); |
| 61 | } |
| 62 | |
| 63 | TraceWriterImpl::TracePacketHandle TraceWriterImpl::NewTracePacket() { |
| 64 | // If we hit this, the caller is calling NewTracePacket() without having |
| 65 | // finalized the previous packet. |
| 66 | PERFETTO_DCHECK(cur_packet_->is_finalized()); |
| 67 | |
| 68 | fragmenting_packet_ = false; |
| 69 | |
| 70 | // TODO: hack to get a new page every time and reduce fragmentation (that |
| 71 | // requires stitching support in the service). |
| 72 | protobuf_stream_writer_.Reset(GetNewBuffer()); |
| 73 | |
| 74 | // Reserve space for the size of the message. Note: this call might re-enter |
| 75 | // into this class invoking GetNewBuffer() if there isn't enough space or if |
| 76 | // this is the very first call to NewTracePacket(). |
| 77 | static_assert( |
| 78 | kPacketHeaderSize == kMessageLengthFieldSize, |
| 79 | "The packet header must match the ProtoZeroMessage header size"); |
| 80 | cur_packet_->Reset(&protobuf_stream_writer_); |
| 81 | uint8_t* header = protobuf_stream_writer_.ReserveBytes(kPacketHeaderSize); |
| 82 | memset(header, 0, kPacketHeaderSize); |
| 83 | cur_packet_->set_size_field(header); |
| 84 | cur_chunk_.IncrementPacketCount(); |
| 85 | TracePacketHandle handle(cur_packet_.get()); |
| 86 | cur_fragment_start_ = protobuf_stream_writer_.write_ptr(); |
| 87 | fragmenting_packet_ = true; |
| 88 | return handle; |
| 89 | } |
| 90 | |
| 91 | // Called by the ProtoZeroMessage. We can get here in two cases: |
| 92 | // 1. In the middle of writing a ProtoZeroMessage, |
| 93 | // when |fragmenting_packet_| == true. In this case we want to update the |
| 94 | // chunk header with a partial packet and start a new partial packet in the |
| 95 | // new chunk. |
| 96 | // 2. While calling ReserveBytes() for the packet header in NewTracePacket(). |
| 97 | // In this case |fragmenting_packet_| == false and we just want a new chunk |
| 98 | // without creating any fragments. |
| 99 | protozero::ContiguousMemoryRange TraceWriterImpl::GetNewBuffer() { |
| 100 | if (fragmenting_packet_) { |
| 101 | uint8_t* const wptr = protobuf_stream_writer_.write_ptr(); |
| 102 | PERFETTO_DCHECK(wptr >= cur_fragment_start_); |
| 103 | uint32_t partial_size = static_cast<uint32_t>(wptr - cur_fragment_start_); |
| 104 | PERFETTO_DCHECK(partial_size < cur_chunk_.size()); |
| 105 | |
| 106 | // Backfill the packet header with the fragment size. |
| 107 | cur_packet_->inc_size_already_written(partial_size); |
| 108 | cur_chunk_.SetFlag(ChunkHeader::kLastPacketContinuesOnNextChunk); |
| 109 | WriteRedundantVarInt(partial_size, cur_packet_->size_field()); |
| 110 | |
| 111 | // Descend in the stack of non-finalized nested submessages (if any) and |
| 112 | // detour their |size_field| into the |patch_list_|. At this point we have |
| 113 | // to release the chunk and they cannot write anymore into that. |
| 114 | // TODO(primiano): add tests to cover this logic. |
| 115 | for (auto* nested_msg = cur_packet_->nested_message(); nested_msg; |
| 116 | nested_msg = nested_msg->nested_message()) { |
| 117 | uint8_t* const cur_hdr = nested_msg->size_field(); |
| 118 | PERFETTO_DCHECK(cur_hdr >= cur_chunk_.payload_begin() && |
| 119 | cur_hdr + kMessageLengthFieldSize <= cur_chunk_.end()); |
| 120 | auto cur_hdr_offset = static_cast<uint16_t>(cur_hdr - cur_chunk_.begin()); |
| 121 | patch_list_.emplace_front(cur_chunk_id_, cur_hdr_offset); |
| 122 | Patch& patch = patch_list_.front(); |
| 123 | nested_msg->set_size_field(patch.size_field); |
| 124 | PERFETTO_DLOG("Created new patchlist entry for protobuf nested message"); |
| 125 | } |
| 126 | } |
| 127 | |
| 128 | if (cur_chunk_.is_valid()) |
| 129 | shmem_arbiter_->ReturnCompletedChunk(std::move(cur_chunk_)); |
| 130 | |
| 131 | // Start a new chunk. |
| 132 | ChunkHeader::Identifier identifier = {}; |
| 133 | identifier.writer_id = id_; |
| 134 | identifier.chunk_id = cur_chunk_id_++; |
| 135 | |
| 136 | ChunkHeader::PacketsState packets_state = {}; |
| 137 | if (fragmenting_packet_) { |
| 138 | packets_state.count = 1; |
| 139 | packets_state.flags = ChunkHeader::kFirstPacketContinuesFromPrevChunk; |
| 140 | } |
| 141 | |
| 142 | // The memory order of the stores below doesn't really matter. This |header| |
| 143 | // is just a local temporary object. The GetNewChunk() call below will copy it |
| 144 | // into the shared buffer with the proper barriers. |
| 145 | ChunkHeader header = {}; |
| 146 | header.identifier.store(identifier, std::memory_order_relaxed); |
| 147 | header.packets_state.store(packets_state, std::memory_order_relaxed); |
| 148 | |
| 149 | cur_chunk_ = shmem_arbiter_->GetNewChunk(header, target_buffer_); |
| 150 | uint8_t* payload_begin = cur_chunk_.payload_begin(); |
| 151 | if (fragmenting_packet_) { |
| 152 | cur_packet_->set_size_field(payload_begin); |
| 153 | memset(payload_begin, 0, kPacketHeaderSize); |
| 154 | payload_begin += kPacketHeaderSize; |
| 155 | cur_fragment_start_ = payload_begin; |
| 156 | } |
| 157 | |
| 158 | return protozero::ContiguousMemoryRange{payload_begin, cur_chunk_.end()}; |
| 159 | } |
| 160 | |
| 161 | WriterID TraceWriterImpl::writer_id() const { |
| 162 | return id_; |
| 163 | }; |
| 164 | |
| 165 | TraceWriterImpl::Patch::Patch(uint16_t cid, uint16_t offset) |
| 166 | : chunk_id(cid), offset_in_chunk(offset) {} |
| 167 | |
| 168 | // Base class ctor/dtor definition. |
| 169 | TraceWriter::TraceWriter() = default; |
| 170 | TraceWriter::~TraceWriter() = default; |
| 171 | |
| 172 | } // namespace perfetto |