ftrace_reader/src/cpu_reader.cc - third_party/perfetto - Git at Google

 /*
  * Copyright (C) 2017 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 "cpu_reader.h"

 #include <utility>

 #include "perfetto_base/logging.h"
 #include "proto_translation_table.h"

 #include "protos/ftrace/ftrace_event.pbzero.h"
 #include "protos/ftrace/print.pbzero.h"
 #include "protos/ftrace/sched_switch.pbzero.h"

 #include "protos/ftrace/ftrace_event_bundle.pbzero.h"

 namespace perfetto {

 namespace {

 using BundleHandle =
     protozero::ProtoZeroMessageHandle<protos::pbzero::FtraceEventBundle>;

 const std::vector<bool> BuildEnabledVector(const ProtoTranslationTable& table,
                                            const std::set<std::string>& names) {
   std::vector<bool> enabled(table.largest_id() + 1);
   for (const std::string& name : names) {
     const ProtoTranslationTable::Event* event = table.GetEventByName(name);
     if (!event)
       continue;
     enabled[event->ftrace_event_id] = true;
   }
   return enabled;
 }

 // For further documentation of these constants see the kernel source:
 // linux/include/linux/ring_buffer.h
 // Some information about the values of these constants are exposed to user
 // space at: /sys/kernel/debug/tracing/events/header_event
 const uint32_t kTypeDataTypeLengthMax = 28;
 const uint32_t kTypePadding = 29;
 const uint32_t kTypeTimeExtend = 30;
 const uint32_t kTypeTimeStamp = 31;

 const size_t kPageSize = 4096;

 struct PageHeader {
   uint64_t timestamp;
   uint32_t size;
   uint32_t : 24;
   uint32_t overwrite : 8;
 };

 struct EventHeader {
   uint32_t type_or_length : 5;
   uint32_t time_delta : 27;
 };

 struct TimeStamp {
   uint64_t tv_nsec;
   uint64_t tv_sec;
 };

 }  // namespace

 EventFilter::EventFilter(const ProtoTranslationTable& table,
                          std::set<std::string> names)
     : enabled_ids_(BuildEnabledVector(table, names)),
       enabled_names_(std::move(names)) {}
 EventFilter::~EventFilter() = default;

 CpuReader::CpuReader(const ProtoTranslationTable* table,
                      size_t cpu,
                      base::ScopedFile fd)
     : table_(table), cpu_(cpu), fd_(std::move(fd)) {}

 int CpuReader::GetFileDescriptor() {
   return fd_.get();
 }

 bool CpuReader::Drain(const std::array<const EventFilter*, kMaxSinks>& filters,
                       const std::array<BundleHandle, kMaxSinks>& bundles) {
   if (!fd_)
     return false;

   uint8_t* buffer = GetBuffer();
   // TOOD(hjd): One read() per page may be too many.
   long bytes = PERFETTO_EINTR(read(fd_.get(), buffer, kPageSize));
   if (bytes == -1 || bytes == 0)
     return false;
   PERFETTO_CHECK(bytes <= (long)kPageSize);

   for (size_t i = 0; i < kMaxSinks; i++) {
     if (!filters[i])
       break;
     bool result =
         ParsePage(cpu_, buffer, bytes, filters[i], &*bundles[i], table_);
     PERFETTO_DCHECK(result);
   }
   return true;
 }

 CpuReader::~CpuReader() = default;

 uint8_t* CpuReader::GetBuffer() {
   // TODO(primiano): Guard against overflows, like BufferedFrameDeserializer.
   if (!buffer_)
     buffer_ = std::unique_ptr<uint8_t[]>(new uint8_t[kPageSize]);
   return buffer_.get();
 }

 // The structure of a raw trace buffer page is as follows:
 // First a page header:
 //   8 bytes of timestamp
 //   8 bytes of page length TODO(hjd): other fields also defined here?
 // // TODO(hjd): Document rest of format.
 // Some information about the layout of the page header is available in user
 // space at: /sys/kernel/debug/tracing/events/header_event
 // This method is deliberately static so it can be tested independently.
 bool CpuReader::ParsePage(size_t cpu,
                           const uint8_t* ptr,
                           size_t size,
                           const EventFilter* filter,
                           protos::pbzero::FtraceEventBundle* bundle,
                           const ProtoTranslationTable* table) {
   // TODO(hjd): Remove when the generic parser comes in.
   const size_t print_id = table->GetEventByName("print")->ftrace_event_id;
   const size_t sched_switch_id =
       table->GetEventByName("sched_switch")->ftrace_event_id;

   const uint8_t* const start_of_page = ptr;
   const uint8_t* const end_of_page = ptr + size;

   bundle->set_cpu(cpu);

   (void)start_of_page;

   // TODO(hjd): Read this format dynamically?
   PageHeader page_header;
   if (!ReadAndAdvance(&ptr, end_of_page, &page_header))
     return false;

   const uint8_t* const end = ptr + page_header.size;
   if (end > end_of_page)
     return false;

   while (ptr < end) {
     EventHeader event_header;
     if (!ReadAndAdvance(&ptr, end, &event_header))
       return false;
     switch (event_header.type_or_length) {
       case kTypePadding: {
         // Left over page padding or discarded event.
         if (event_header.time_delta == 0) {
           // TODO(hjd): Look at the next few bytes for read size;
           PERFETTO_CHECK(false);  // TODO(hjd): Handle
         }
         uint32_t length;
         if (!ReadAndAdvance<uint32_t>(&ptr, end, &length))
           return false;
         ptr += length;
         break;
       }
       case kTypeTimeExtend: {
         // Extend the time delta.
         uint32_t time_delta_ext;
         if (!ReadAndAdvance<uint32_t>(&ptr, end, &time_delta_ext))
           return false;
         (void)time_delta_ext;
         // TODO(hjd): Handle.
         break;
       }
       case kTypeTimeStamp: {
         // Sync time stamp with external clock.
         TimeStamp time_stamp;
         if (!ReadAndAdvance<TimeStamp>(&ptr, end, &time_stamp))
           return false;
         // TODO(hjd): Handle.
         break;
       }
       // Data record:
       default: {
         PERFETTO_CHECK(event_header.type_or_length <= kTypeDataTypeLengthMax);
         // type_or_length is <=28 so it represents the length of a data record.
         if (event_header.type_or_length == 0) {
           // TODO(hjd): Look at the next few bytes for real size.
           PERFETTO_CHECK(false);
         }
         const uint8_t* next = ptr + 4 * event_header.type_or_length;

         uint16_t ftrace_event_id;
         if (!ReadAndAdvance<uint16_t>(&ptr, end, &ftrace_event_id))
           return false;
         if (!filter->IsEventEnabled(ftrace_event_id)) {
           ptr = next;
           break;
         }

         // Common headers:
         // TODO(hjd): Read this format dynamically?
         uint8_t flags;
         uint8_t preempt_count;
         uint32_t pid;
         if (!ReadAndAdvance<uint8_t>(&ptr, end, &flags))
           return false;
         if (!ReadAndAdvance<uint8_t>(&ptr, end, &preempt_count))
           return false;
         if (!ReadAndAdvance<uint32_t>(&ptr, end, &pid))
           return false;

         // PERFETTO_DLOG("Event type=%d pid=%d", ftrace_event_id, pid);

         protos::pbzero::FtraceEvent* event = bundle->add_event();
         event->set_pid(pid);

         // TODO(hjd): Replace this handrolled code with generic parsing code.
         if (ftrace_event_id == print_id) {
           protos::pbzero::PrintFtraceEvent* print_event = event->set_print();
           // Trace Marker Parser
           uint64_t ip;
           if (!ReadAndAdvance<uint64_t>(&ptr, end, &ip))
             return false;
           print_event->set_ip(ip);

           // TODO(hjd): Not sure if this is null-terminated.
           const uint8_t* buf_start = ptr;
           const uint8_t* buf_end = next - 2;
           print_event->set_buf(reinterpret_cast<const char*>(buf_start),
                                buf_end - buf_start);
           print_event->Finalize();
         }

         // TODO(hjd): Replace this handrolled code with generic parsing code.
         if (ftrace_event_id == sched_switch_id) {
           protos::pbzero::SchedSwitchFtraceEvent* switch_event =
               event->set_sched_switch();

           char prev_comm[16];
           uint32_t prev_pid;
           uint32_t prev_prio;
           uint64_t prev_state;
           char next_comm[16];
           uint32_t next_pid;
           uint32_t next_prio;

           // TODO(hjd): Avoid this copy.
           if (!ReadAndAdvance<char[16]>(&ptr, end, &prev_comm))
             return false;
           if (!ReadAndAdvance<uint32_t>(&ptr, end, &prev_pid))
             return false;
           if (!ReadAndAdvance<uint32_t>(&ptr, end, &prev_prio))
             return false;
           if (!ReadAndAdvance<uint64_t>(&ptr, end, &prev_state))
             return false;
           if (!ReadAndAdvance<char[16]>(&ptr, end, &next_comm))
             return false;
           if (!ReadAndAdvance<uint32_t>(&ptr, end, &next_pid))
             return false;
           if (!ReadAndAdvance<uint32_t>(&ptr, end, &next_prio))
             return false;
           // TODO(hjd): Not sure if this is null-terminated.
           prev_comm[15] = '\0';
           switch_event->set_prev_comm(prev_comm);
           switch_event->set_prev_pid(prev_pid);
           switch_event->set_prev_prio(prev_prio);
           switch_event->set_prev_state(prev_state);
           // TODO(hjd): Not sure if this is null-terminated.
           next_comm[15] = '\0';
           switch_event->set_next_comm(next_comm);
           switch_event->set_next_pid(next_pid);
           switch_event->set_next_prio(next_prio);
           switch_event->Finalize();
         }

         event->Finalize();

         // Jump to next event.
         ptr = next;
       }
     }
   }
   return true;
 }

 }  // namespace perfetto
	/*
	* Copyright (C) 2017 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 "cpu_reader.h"

	#include <utility>

	#include "perfetto_base/logging.h"
	#include "proto_translation_table.h"

	#include "protos/ftrace/ftrace_event.pbzero.h"
	#include "protos/ftrace/print.pbzero.h"
	#include "protos/ftrace/sched_switch.pbzero.h"

	#include "protos/ftrace/ftrace_event_bundle.pbzero.h"

	namespace perfetto {

	namespace {

	using BundleHandle =
	protozero::ProtoZeroMessageHandle<protos::pbzero::FtraceEventBundle>;

	const std::vector<bool> BuildEnabledVector(const ProtoTranslationTable& table,
	const std::set<std::string>& names) {
	std::vector<bool> enabled(table.largest_id() + 1);
	for (const std::string& name : names) {
	const ProtoTranslationTable::Event* event = table.GetEventByName(name);
	if (!event)
	continue;
	enabled[event->ftrace_event_id] = true;
	}
	return enabled;
	}

	// For further documentation of these constants see the kernel source:
	// linux/include/linux/ring_buffer.h
	// Some information about the values of these constants are exposed to user
	// space at: /sys/kernel/debug/tracing/events/header_event
	const uint32_t kTypeDataTypeLengthMax = 28;
	const uint32_t kTypePadding = 29;
	const uint32_t kTypeTimeExtend = 30;
	const uint32_t kTypeTimeStamp = 31;

	const size_t kPageSize = 4096;

	struct PageHeader {
	uint64_t timestamp;
	uint32_t size;
	uint32_t : 24;
	uint32_t overwrite : 8;
	};

	struct EventHeader {
	uint32_t type_or_length : 5;
	uint32_t time_delta : 27;
	};

	struct TimeStamp {
	uint64_t tv_nsec;
	uint64_t tv_sec;
	};

	} // namespace

	EventFilter::EventFilter(const ProtoTranslationTable& table,
	std::set<std::string> names)
	: enabled_ids_(BuildEnabledVector(table, names)),
	enabled_names_(std::move(names)) {}
	EventFilter::~EventFilter() = default;

	CpuReader::CpuReader(const ProtoTranslationTable* table,
	size_t cpu,
	base::ScopedFile fd)
	: table_(table), cpu_(cpu), fd_(std::move(fd)) {}

	int CpuReader::GetFileDescriptor() {
	return fd_.get();
	}

	bool CpuReader::Drain(const std::array<const EventFilter*, kMaxSinks>& filters,
	const std::array<BundleHandle, kMaxSinks>& bundles) {
	if (!fd_)
	return false;

	uint8_t* buffer = GetBuffer();
	// TOOD(hjd): One read() per page may be too many.
	long bytes = PERFETTO_EINTR(read(fd_.get(), buffer, kPageSize));
	if (bytes == -1 \|\| bytes == 0)
	return false;
	PERFETTO_CHECK(bytes <= (long)kPageSize);

	for (size_t i = 0; i < kMaxSinks; i++) {
	if (!filters[i])
	break;
	bool result =
	ParsePage(cpu_, buffer, bytes, filters[i], &*bundles[i], table_);
	PERFETTO_DCHECK(result);
	}
	return true;
	}

	CpuReader::~CpuReader() = default;

	uint8_t* CpuReader::GetBuffer() {
	// TODO(primiano): Guard against overflows, like BufferedFrameDeserializer.
	if (!buffer_)
	buffer_ = std::unique_ptr<uint8_t[]>(new uint8_t[kPageSize]);
	return buffer_.get();
	}

	// The structure of a raw trace buffer page is as follows:
	// First a page header:
	// 8 bytes of timestamp
	// 8 bytes of page length TODO(hjd): other fields also defined here?
	// // TODO(hjd): Document rest of format.
	// Some information about the layout of the page header is available in user
	// space at: /sys/kernel/debug/tracing/events/header_event
	// This method is deliberately static so it can be tested independently.
	bool CpuReader::ParsePage(size_t cpu,
	const uint8_t* ptr,
	size_t size,
	const EventFilter* filter,
	protos::pbzero::FtraceEventBundle* bundle,
	const ProtoTranslationTable* table) {
	// TODO(hjd): Remove when the generic parser comes in.
	const size_t print_id = table->GetEventByName("print")->ftrace_event_id;
	const size_t sched_switch_id =
	table->GetEventByName("sched_switch")->ftrace_event_id;

	const uint8_t* const start_of_page = ptr;
	const uint8_t* const end_of_page = ptr + size;

	bundle->set_cpu(cpu);

	(void)start_of_page;

	// TODO(hjd): Read this format dynamically?
	PageHeader page_header;
	if (!ReadAndAdvance(&ptr, end_of_page, &page_header))
	return false;

	const uint8_t* const end = ptr + page_header.size;
	if (end > end_of_page)
	return false;

	while (ptr < end) {
	EventHeader event_header;
	if (!ReadAndAdvance(&ptr, end, &event_header))
	return false;
	switch (event_header.type_or_length) {
	case kTypePadding: {
	// Left over page padding or discarded event.
	if (event_header.time_delta == 0) {
	// TODO(hjd): Look at the next few bytes for read size;
	PERFETTO_CHECK(false); // TODO(hjd): Handle
	}
	uint32_t length;
	if (!ReadAndAdvance<uint32_t>(&ptr, end, &length))
	return false;
	ptr += length;
	break;
	}
	case kTypeTimeExtend: {
	// Extend the time delta.
	uint32_t time_delta_ext;
	if (!ReadAndAdvance<uint32_t>(&ptr, end, &time_delta_ext))
	return false;
	(void)time_delta_ext;
	// TODO(hjd): Handle.
	break;
	}
	case kTypeTimeStamp: {
	// Sync time stamp with external clock.
	TimeStamp time_stamp;
	if (!ReadAndAdvance<TimeStamp>(&ptr, end, &time_stamp))
	return false;
	// TODO(hjd): Handle.
	break;
	}
	// Data record:
	default: {
	PERFETTO_CHECK(event_header.type_or_length <= kTypeDataTypeLengthMax);
	// type_or_length is <=28 so it represents the length of a data record.
	if (event_header.type_or_length == 0) {
	// TODO(hjd): Look at the next few bytes for real size.
	PERFETTO_CHECK(false);
	}
	const uint8_t* next = ptr + 4 * event_header.type_or_length;

	uint16_t ftrace_event_id;
	if (!ReadAndAdvance<uint16_t>(&ptr, end, &ftrace_event_id))
	return false;
	if (!filter->IsEventEnabled(ftrace_event_id)) {
	ptr = next;
	break;
	}

	// Common headers:
	// TODO(hjd): Read this format dynamically?
	uint8_t flags;
	uint8_t preempt_count;
	uint32_t pid;
	if (!ReadAndAdvance<uint8_t>(&ptr, end, &flags))
	return false;
	if (!ReadAndAdvance<uint8_t>(&ptr, end, &preempt_count))
	return false;
	if (!ReadAndAdvance<uint32_t>(&ptr, end, &pid))
	return false;

	// PERFETTO_DLOG("Event type=%d pid=%d", ftrace_event_id, pid);

	protos::pbzero::FtraceEvent* event = bundle->add_event();
	event->set_pid(pid);

	// TODO(hjd): Replace this handrolled code with generic parsing code.
	if (ftrace_event_id == print_id) {
	protos::pbzero::PrintFtraceEvent* print_event = event->set_print();
	// Trace Marker Parser
	uint64_t ip;
	if (!ReadAndAdvance<uint64_t>(&ptr, end, &ip))
	return false;
	print_event->set_ip(ip);

	// TODO(hjd): Not sure if this is null-terminated.
	const uint8_t* buf_start = ptr;
	const uint8_t* buf_end = next - 2;
	print_event->set_buf(reinterpret_cast<const char*>(buf_start),
	buf_end - buf_start);
	print_event->Finalize();
	}

	// TODO(hjd): Replace this handrolled code with generic parsing code.
	if (ftrace_event_id == sched_switch_id) {
	protos::pbzero::SchedSwitchFtraceEvent* switch_event =
	event->set_sched_switch();

	char prev_comm[16];
	uint32_t prev_pid;
	uint32_t prev_prio;
	uint64_t prev_state;
	char next_comm[16];
	uint32_t next_pid;
	uint32_t next_prio;

	// TODO(hjd): Avoid this copy.
	if (!ReadAndAdvance<char[16]>(&ptr, end, &prev_comm))
	return false;
	if (!ReadAndAdvance<uint32_t>(&ptr, end, &prev_pid))
	return false;
	if (!ReadAndAdvance<uint32_t>(&ptr, end, &prev_prio))
	return false;
	if (!ReadAndAdvance<uint64_t>(&ptr, end, &prev_state))
	return false;
	if (!ReadAndAdvance<char[16]>(&ptr, end, &next_comm))
	return false;
	if (!ReadAndAdvance<uint32_t>(&ptr, end, &next_pid))
	return false;
	if (!ReadAndAdvance<uint32_t>(&ptr, end, &next_prio))
	return false;
	// TODO(hjd): Not sure if this is null-terminated.
	prev_comm[15] = '\0';
	switch_event->set_prev_comm(prev_comm);
	switch_event->set_prev_pid(prev_pid);
	switch_event->set_prev_prio(prev_prio);
	switch_event->set_prev_state(prev_state);
	// TODO(hjd): Not sure if this is null-terminated.
	next_comm[15] = '\0';
	switch_event->set_next_comm(next_comm);
	switch_event->set_next_pid(next_pid);
	switch_event->set_next_prio(next_prio);
	switch_event->Finalize();
	}

	event->Finalize();

	// Jump to next event.
	ptr = next;
	}
	}
	}
	return true;
	}

	} // namespace perfetto