src/trace_processor/importers/ftrace/ftrace_tokenizer.cc

/*
 * Copyright (C) 2019 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "src/trace_processor/importers/ftrace/ftrace_tokenizer.h"

#include "perfetto/base/logging.h"
#include "perfetto/protozero/proto_decoder.h"
#include "perfetto/protozero/proto_utils.h"
#include "src/trace_processor/stats.h"
#include "src/trace_processor/trace_sorter.h"
#include "src/trace_processor/trace_storage.h"

#include "protos/perfetto/trace/ftrace/ftrace_event.pbzero.h"
#include "protos/perfetto/trace/ftrace/ftrace_event_bundle.pbzero.h"

namespace perfetto {
namespace trace_processor {

using protozero::ProtoDecoder;
using protozero::proto_utils::MakeTagLengthDelimited;
using protozero::proto_utils::MakeTagVarInt;
using protozero::proto_utils::ParseVarInt;

PERFETTO_ALWAYS_INLINE
void FtraceTokenizer::TokenizeFtraceBundle(TraceBlobView bundle) {
  protos::pbzero::FtraceEventBundle::Decoder decoder(bundle.data(),
                                                     bundle.length());

  if (PERFETTO_UNLIKELY(!decoder.has_cpu())) {
    PERFETTO_ELOG("CPU field not found in FtraceEventBundle");
    context_->storage->IncrementStats(stats::ftrace_bundle_tokenizer_errors);
    return;
  }

  uint32_t cpu = decoder.cpu();
  if (PERFETTO_UNLIKELY(cpu > base::kMaxCpus)) {
    PERFETTO_ELOG("CPU larger than kMaxCpus (%u > %zu)", cpu, base::kMaxCpus);
    return;
  }

  if (decoder.has_compact_sched()) {
    TokenizeFtraceCompactSched(cpu, decoder.compact_sched().data,
                               decoder.compact_sched().size);
  }

  for (auto it = decoder.event(); it; ++it) {
    protozero::ConstBytes event = *it;
    size_t off = bundle.offset_of(event.data);
    TokenizeFtraceEvent(cpu, bundle.slice(off, event.size));
  }
  context_->sorter->FinalizeFtraceEventBatch(cpu);
}

PERFETTO_ALWAYS_INLINE
void FtraceTokenizer::TokenizeFtraceEvent(uint32_t cpu, TraceBlobView event) {
  constexpr auto kTimestampFieldNumber =
      protos::pbzero::FtraceEvent::kTimestampFieldNumber;
  const uint8_t* data = event.data();
  const size_t length = event.length();
  ProtoDecoder decoder(data, length);
  uint64_t raw_timestamp = 0;
  bool timestamp_found = false;

  // Speculate on the fact that the timestamp is often the 1st field of the
  // event.
  constexpr auto timestampFieldTag = MakeTagVarInt(kTimestampFieldNumber);
  if (PERFETTO_LIKELY(length > 10 && data[0] == timestampFieldTag)) {
    // Fastpath.
    const uint8_t* next = ParseVarInt(data + 1, data + 11, &raw_timestamp);
    timestamp_found = next != data + 1;
    decoder.Reset(next);
  } else {
    // Slowpath.
    if (auto ts_field = decoder.FindField(kTimestampFieldNumber)) {
      timestamp_found = true;
      raw_timestamp = ts_field.as_uint64();
    }
  }

  if (PERFETTO_UNLIKELY(!timestamp_found)) {
    PERFETTO_ELOG("Timestamp field not found in FtraceEvent");
    context_->storage->IncrementStats(stats::ftrace_bundle_tokenizer_errors);
    return;
  }

  int64_t timestamp = static_cast<int64_t>(raw_timestamp);

  // We don't need to parse this packet, just push it to be sorted with
  // the timestamp.
  context_->sorter->PushFtraceEvent(cpu, timestamp, std::move(event));
}

PERFETTO_ALWAYS_INLINE
void FtraceTokenizer::TokenizeFtraceCompactSched(uint32_t cpu,
                                                 const uint8_t* data,
                                                 size_t size) {
  protos::pbzero::FtraceEventBundle::CompactSched::Decoder compact_sched(data,
                                                                         size);
  // Build the interning table for comm fields.
  std::vector<StringId> string_table;
  string_table.reserve(512);
  for (auto it = compact_sched.intern_table(); it; it++) {
    StringId value = context_->storage->InternString(*it);
    string_table.push_back(value);
  }

  TokenizeFtraceCompactSchedSwitch(cpu, compact_sched, string_table);
  TokenizeFtraceCompactSchedWaking(cpu, compact_sched, string_table);
}

void FtraceTokenizer::TokenizeFtraceCompactSchedSwitch(
    uint32_t cpu,
    const protos::pbzero::FtraceEventBundle::CompactSched::Decoder& compact,
    const std::vector<StringId>& string_table) {
  // Accumulator for timestamp deltas.
  int64_t timestamp_acc = 0;

  // The events' fields are stored in a structure-of-arrays style, using packed
  // repeated fields. Walk each repeated field in step to recover individual
  // events.
  bool parse_error = false;
  auto timestamp_it = compact.switch_timestamp(&parse_error);
  auto pstate_it = compact.switch_prev_state(&parse_error);
  auto npid_it = compact.switch_next_pid(&parse_error);
  auto nprio_it = compact.switch_next_prio(&parse_error);
  auto comm_it = compact.switch_next_comm_index(&parse_error);
  for (; timestamp_it && pstate_it && npid_it && nprio_it && comm_it;
       ++timestamp_it, ++pstate_it, ++npid_it, ++nprio_it, ++comm_it) {
    InlineSchedSwitch event{};

    // delta-encoded timestamp
    timestamp_acc += static_cast<int64_t>(*timestamp_it);
    int64_t event_timestamp = timestamp_acc;

    // index into the interned string table
    PERFETTO_DCHECK(*comm_it < string_table.size());
    event.next_comm = string_table[*comm_it];

    event.prev_state = *pstate_it;
    event.next_pid = *npid_it;
    event.next_prio = *nprio_it;

    context_->sorter->PushInlineFtraceEvent(cpu, event_timestamp,
                                            InlineEvent::SchedSwitch(event));
  }

  // Check that all packed buffers were decoded correctly, and fully.
  bool sizes_match =
      !timestamp_it && !pstate_it && !npid_it && !nprio_it && !comm_it;
  if (parse_error || !sizes_match)
    context_->storage->IncrementStats(stats::compact_sched_has_parse_errors);
}

void FtraceTokenizer::TokenizeFtraceCompactSchedWaking(
    uint32_t cpu,
    const protos::pbzero::FtraceEventBundle::CompactSched::Decoder& compact,
    const std::vector<StringId>& string_table) {
  // Accumulator for timestamp deltas.
  int64_t timestamp_acc = 0;

  // The events' fields are stored in a structure-of-arrays style, using packed
  // repeated fields. Walk each repeated field in step to recover individual
  // events.
  bool parse_error = false;
  auto timestamp_it = compact.waking_timestamp(&parse_error);
  auto pid_it = compact.waking_pid(&parse_error);
  auto tcpu_it = compact.waking_target_cpu(&parse_error);
  auto prio_it = compact.waking_prio(&parse_error);
  auto comm_it = compact.waking_comm_index(&parse_error);

  for (; timestamp_it && pid_it && tcpu_it && prio_it && comm_it;
       ++timestamp_it, ++pid_it, ++tcpu_it, ++prio_it, ++comm_it) {
    InlineSchedWaking event{};

    // delta-encoded timestamp
    timestamp_acc += static_cast<int64_t>(*timestamp_it);
    int64_t event_timestamp = timestamp_acc;

    // index into the interned string table
    PERFETTO_DCHECK(*comm_it < string_table.size());
    event.comm = string_table[*comm_it];

    event.pid = *pid_it;
    event.target_cpu = *tcpu_it;
    event.prio = *prio_it;

    context_->sorter->PushInlineFtraceEvent(cpu, event_timestamp,
                                            InlineEvent::SchedWaking(event));
  }

  // Check that all packed buffers were decoded correctly, and fully.
  bool sizes_match =
      !timestamp_it && !pid_it && !tcpu_it && !prio_it && !comm_it;
  if (parse_error || !sizes_match)
    context_->storage->IncrementStats(stats::compact_sched_has_parse_errors);
}

}  // namespace trace_processor
}  // namespace perfetto