src/traced/probes/ftrace/compact_sched.cc - third_party/perfetto - Git at Google

 /*
  * 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/traced/probes/ftrace/compact_sched.h"

 #include <stdint.h>
 #include <optional>

 #include "protos/perfetto/config/ftrace/ftrace_config.gen.h"
 #include "protos/perfetto/trace/ftrace/ftrace_event.pbzero.h"
 #include "protos/perfetto/trace/ftrace/sched.pbzero.h"
 #include "src/traced/probes/ftrace/event_info_constants.h"
 #include "src/traced/probes/ftrace/ftrace_config_utils.h"

 namespace perfetto {

 namespace {

 // Pre-parse the format of sched_switch, checking if our simplifying
 // assumptions about possible widths/signedness hold, and record the subset
 // of the format that will be used during parsing.
 std::optional<CompactSchedSwitchFormat> ValidateSchedSwitchFormat(
     const Event& event) {
   using protos::pbzero::SchedSwitchFtraceEvent;

   CompactSchedSwitchFormat switch_format;
   switch_format.event_id = event.ftrace_event_id;
   switch_format.size = event.size;

   bool prev_state_valid = false;
   bool next_pid_valid = false;
   bool next_prio_valid = false;
   bool next_comm_valid = false;
   for (const auto& field : event.fields) {
     switch (field.proto_field_id) {
       case SchedSwitchFtraceEvent::kPrevStateFieldNumber:
         switch_format.prev_state_offset = field.ftrace_offset;
         switch_format.prev_state_type = field.ftrace_type;

         // kernel type: long
         prev_state_valid = (field.ftrace_type == kFtraceInt32 ||
                             field.ftrace_type == kFtraceInt64);
         break;

       case SchedSwitchFtraceEvent::kNextPidFieldNumber:
         switch_format.next_pid_offset = field.ftrace_offset;
         switch_format.next_pid_type = field.ftrace_type;

         // kernel type: pid_t
         next_pid_valid = (field.ftrace_type == kFtracePid32);
         break;

       case SchedSwitchFtraceEvent::kNextPrioFieldNumber:
         switch_format.next_prio_offset = field.ftrace_offset;
         switch_format.next_prio_type = field.ftrace_type;

         // kernel type: int
         next_prio_valid = (field.ftrace_type == kFtraceInt32);
         break;

       case SchedSwitchFtraceEvent::kNextCommFieldNumber:
         switch_format.next_comm_offset = field.ftrace_offset;

         next_comm_valid =
             (field.ftrace_type == kFtraceFixedCString &&
              field.ftrace_size == CommInterner::kExpectedCommLength);
         break;
       default:
         break;
     }
   }

   if (!prev_state_valid || !next_pid_valid || !next_prio_valid ||
       !next_comm_valid) {
     return std::nullopt;
   }
   return std::make_optional(switch_format);
 }

 // Pre-parse the format of sched_waking, checking if our simplifying
 // assumptions about possible widths/signedness hold, and record the subset
 // of the format that will be used during parsing.
 std::optional<CompactSchedWakingFormat> ValidateSchedWakingFormat(
     const Event& event,
     const std::vector<Field>& common_fields) {
   using protos::pbzero::FtraceEvent;
   using protos::pbzero::SchedWakingFtraceEvent;

   CompactSchedWakingFormat waking_format;
   waking_format.event_id = event.ftrace_event_id;
   waking_format.size = event.size;

   bool pid_valid = false;
   bool target_cpu_valid = false;
   bool prio_valid = false;
   bool comm_valid = false;
   bool common_flags_valid = false;

   for (const Field& field : common_fields) {
     if (field.proto_field_id == FtraceEvent::kCommonFlagsFieldNumber) {
       waking_format.common_flags_offset = field.ftrace_offset;
       waking_format.common_flags_type = field.ftrace_type;

       common_flags_valid = (field.ftrace_type == kFtraceUint8);
       break;
     }
   }

   for (const Field& field : event.fields) {
     switch (field.proto_field_id) {
       case SchedWakingFtraceEvent::kPidFieldNumber:
         waking_format.pid_offset = field.ftrace_offset;
         waking_format.pid_type = field.ftrace_type;

         // kernel type: pid_t
         pid_valid = (field.ftrace_type == kFtracePid32);
         break;

       case SchedWakingFtraceEvent::kTargetCpuFieldNumber:
         waking_format.target_cpu_offset = field.ftrace_offset;
         waking_format.target_cpu_type = field.ftrace_type;

         // kernel type: int
         target_cpu_valid = (field.ftrace_type == kFtraceInt32);
         break;

       case SchedWakingFtraceEvent::kPrioFieldNumber:
         waking_format.prio_offset = field.ftrace_offset;
         waking_format.prio_type = field.ftrace_type;

         // kernel type: int
         prio_valid = (field.ftrace_type == kFtraceInt32);
         break;

       case SchedWakingFtraceEvent::kCommFieldNumber:
         waking_format.comm_offset = field.ftrace_offset;

         comm_valid = (field.ftrace_type == kFtraceFixedCString &&
                       field.ftrace_size == CommInterner::kExpectedCommLength);
         break;
       default:
         break;
     }
   }

   if (!pid_valid || !target_cpu_valid || !prio_valid || !comm_valid ||
       !common_flags_valid) {
     return std::nullopt;
   }
   return std::make_optional(waking_format);
 }

 }  // namespace

 // TODO(rsavitski): could avoid looping over all events if the caller did the
 // work to remember the relevant events (translation table construction already
 // loops over them).
 CompactSchedEventFormat ValidateFormatForCompactSched(
     const std::vector<Event>& events,
     const std::vector<Field>& common_fields) {
   using protos::pbzero::FtraceEvent;

   std::optional<CompactSchedSwitchFormat> switch_format;
   std::optional<CompactSchedWakingFormat> waking_format;
   for (const Event& event : events) {
     if (event.proto_field_id == FtraceEvent::kSchedSwitchFieldNumber) {
       switch_format = ValidateSchedSwitchFormat(event);
     }
     if (event.proto_field_id == FtraceEvent::kSchedWakingFieldNumber) {
       waking_format = ValidateSchedWakingFormat(event, common_fields);
     }
   }

   if (switch_format.has_value() && waking_format.has_value()) {
     return CompactSchedEventFormat{/*format_valid=*/true, switch_format.value(),
                                    waking_format.value()};
   } else {
     PERFETTO_ELOG("Unexpected sched_switch or sched_waking format.");
     return CompactSchedEventFormat{/*format_valid=*/false,
                                    CompactSchedSwitchFormat{},
                                    CompactSchedWakingFormat{}};
   }
 }

 CompactSchedEventFormat InvalidCompactSchedEventFormatForTesting() {
   return CompactSchedEventFormat{/*format_valid=*/false,
                                  CompactSchedSwitchFormat{},
                                  CompactSchedWakingFormat{}};
 }

 // TODO(rsavitski): find the correct place in the trace for, and method of,
 // reporting rejection of compact_sched due to compile-time assumptions not
 // holding at runtime.
 CompactSchedConfig CreateCompactSchedConfig(
     const FtraceConfig& request,
     const CompactSchedEventFormat& compact_format) {
   if (!request.compact_sched().enabled())
     return CompactSchedConfig{/*enabled=*/false};

   if (!compact_format.format_valid)
     return CompactSchedConfig{/*enabled=*/false};

   return CompactSchedConfig{/*enabled=*/true};
 }

 CompactSchedConfig EnabledCompactSchedConfigForTesting() {
   return CompactSchedConfig{/*enabled=*/true};
 }

 CompactSchedConfig DisabledCompactSchedConfigForTesting() {
   return CompactSchedConfig{/*enabled=*/false};
 }

 // Check size of stack-allocated bundle state.
 static_assert(sizeof(CompactSchedBuffer) <= 1 << 18,
               "CompactSchedBuffer's on-stack size excessively large.");

 void CompactSchedSwitchBuffer::Write(
     protos::pbzero::FtraceEventBundle::CompactSched* compact_out) const {
   compact_out->set_switch_timestamp(timestamp_);
   compact_out->set_switch_next_pid(next_pid_);
   compact_out->set_switch_prev_state(prev_state_);
   compact_out->set_switch_next_prio(next_prio_);
   compact_out->set_switch_next_comm_index(next_comm_index_);
 }

 void CompactSchedSwitchBuffer::Reset() {
   last_timestamp_ = 0;
   timestamp_.Reset();
   next_pid_.Reset();
   prev_state_.Reset();
   next_prio_.Reset();
   next_comm_index_.Reset();
 }

 void CompactSchedWakingBuffer::Write(
     protos::pbzero::FtraceEventBundle::CompactSched* compact_out) const {
   compact_out->set_waking_timestamp(timestamp_);
   compact_out->set_waking_pid(pid_);
   compact_out->set_waking_target_cpu(target_cpu_);
   compact_out->set_waking_prio(prio_);
   compact_out->set_waking_comm_index(comm_index_);
   compact_out->set_waking_common_flags(common_flags_);
 }

 void CompactSchedWakingBuffer::Reset() {
   last_timestamp_ = 0;
   timestamp_.Reset();
   pid_.Reset();
   target_cpu_.Reset();
   prio_.Reset();
   comm_index_.Reset();
   common_flags_.Reset();
 }

 void CommInterner::Write(
     protos::pbzero::FtraceEventBundle::CompactSched* compact_out) const {
   for (size_t i = 0; i < interned_comms_size_; i++) {
     compact_out->add_intern_table(interned_comms_[i].data(),
                                   interned_comms_[i].size());
   }
 }

 void CommInterner::Reset() {
   intern_buf_write_pos_ = 0;
   interned_comms_size_ = 0;
 }

 void CompactSchedBuffer::WriteAndReset(
     protos::pbzero::FtraceEventBundle* bundle) {
   if (switch_.size() > 0 || waking_.size() > 0) {
     auto* compact_out = bundle->set_compact_sched();

     PERFETTO_DCHECK(interner_.interned_comms_size() > 0);
     interner_.Write(compact_out);

     if (switch_.size() > 0)
       switch_.Write(compact_out);

     if (waking_.size() > 0)
       waking_.Write(compact_out);
   }
   Reset();
 }

 void CompactSchedBuffer::Reset() {
   interner_.Reset();
   switch_.Reset();
   waking_.Reset();
 }

 }  // namespace perfetto
	/*
	* 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/traced/probes/ftrace/compact_sched.h"

	#include <stdint.h>
	#include <optional>

	#include "protos/perfetto/config/ftrace/ftrace_config.gen.h"
	#include "protos/perfetto/trace/ftrace/ftrace_event.pbzero.h"
	#include "protos/perfetto/trace/ftrace/sched.pbzero.h"
	#include "src/traced/probes/ftrace/event_info_constants.h"
	#include "src/traced/probes/ftrace/ftrace_config_utils.h"

	namespace perfetto {

	namespace {

	// Pre-parse the format of sched_switch, checking if our simplifying
	// assumptions about possible widths/signedness hold, and record the subset
	// of the format that will be used during parsing.
	std::optional<CompactSchedSwitchFormat> ValidateSchedSwitchFormat(
	const Event& event) {
	using protos::pbzero::SchedSwitchFtraceEvent;

	CompactSchedSwitchFormat switch_format;
	switch_format.event_id = event.ftrace_event_id;
	switch_format.size = event.size;

	bool prev_state_valid = false;
	bool next_pid_valid = false;
	bool next_prio_valid = false;
	bool next_comm_valid = false;
	for (const auto& field : event.fields) {
	switch (field.proto_field_id) {
	case SchedSwitchFtraceEvent::kPrevStateFieldNumber:
	switch_format.prev_state_offset = field.ftrace_offset;
	switch_format.prev_state_type = field.ftrace_type;

	// kernel type: long
	prev_state_valid = (field.ftrace_type == kFtraceInt32 \|\|
	field.ftrace_type == kFtraceInt64);
	break;

	case SchedSwitchFtraceEvent::kNextPidFieldNumber:
	switch_format.next_pid_offset = field.ftrace_offset;
	switch_format.next_pid_type = field.ftrace_type;

	// kernel type: pid_t
	next_pid_valid = (field.ftrace_type == kFtracePid32);
	break;

	case SchedSwitchFtraceEvent::kNextPrioFieldNumber:
	switch_format.next_prio_offset = field.ftrace_offset;
	switch_format.next_prio_type = field.ftrace_type;

	// kernel type: int
	next_prio_valid = (field.ftrace_type == kFtraceInt32);
	break;

	case SchedSwitchFtraceEvent::kNextCommFieldNumber:
	switch_format.next_comm_offset = field.ftrace_offset;

	next_comm_valid =
	(field.ftrace_type == kFtraceFixedCString &&
	field.ftrace_size == CommInterner::kExpectedCommLength);
	break;
	default:
	break;
	}
	}

	if (!prev_state_valid \|\| !next_pid_valid \|\| !next_prio_valid \|\|
	!next_comm_valid) {
	return std::nullopt;
	}
	return std::make_optional(switch_format);
	}

	// Pre-parse the format of sched_waking, checking if our simplifying
	// assumptions about possible widths/signedness hold, and record the subset
	// of the format that will be used during parsing.
	std::optional<CompactSchedWakingFormat> ValidateSchedWakingFormat(
	const Event& event,
	const std::vector<Field>& common_fields) {
	using protos::pbzero::FtraceEvent;
	using protos::pbzero::SchedWakingFtraceEvent;

	CompactSchedWakingFormat waking_format;
	waking_format.event_id = event.ftrace_event_id;
	waking_format.size = event.size;

	bool pid_valid = false;
	bool target_cpu_valid = false;
	bool prio_valid = false;
	bool comm_valid = false;
	bool common_flags_valid = false;

	for (const Field& field : common_fields) {
	if (field.proto_field_id == FtraceEvent::kCommonFlagsFieldNumber) {
	waking_format.common_flags_offset = field.ftrace_offset;
	waking_format.common_flags_type = field.ftrace_type;

	common_flags_valid = (field.ftrace_type == kFtraceUint8);
	break;
	}
	}

	for (const Field& field : event.fields) {
	switch (field.proto_field_id) {
	case SchedWakingFtraceEvent::kPidFieldNumber:
	waking_format.pid_offset = field.ftrace_offset;
	waking_format.pid_type = field.ftrace_type;

	// kernel type: pid_t
	pid_valid = (field.ftrace_type == kFtracePid32);
	break;

	case SchedWakingFtraceEvent::kTargetCpuFieldNumber:
	waking_format.target_cpu_offset = field.ftrace_offset;
	waking_format.target_cpu_type = field.ftrace_type;

	// kernel type: int
	target_cpu_valid = (field.ftrace_type == kFtraceInt32);
	break;

	case SchedWakingFtraceEvent::kPrioFieldNumber:
	waking_format.prio_offset = field.ftrace_offset;
	waking_format.prio_type = field.ftrace_type;

	// kernel type: int
	prio_valid = (field.ftrace_type == kFtraceInt32);
	break;

	case SchedWakingFtraceEvent::kCommFieldNumber:
	waking_format.comm_offset = field.ftrace_offset;

	comm_valid = (field.ftrace_type == kFtraceFixedCString &&
	field.ftrace_size == CommInterner::kExpectedCommLength);
	break;
	default:
	break;
	}
	}

	if (!pid_valid \|\| !target_cpu_valid \|\| !prio_valid \|\| !comm_valid \|\|
	!common_flags_valid) {
	return std::nullopt;
	}
	return std::make_optional(waking_format);
	}

	} // namespace

	// TODO(rsavitski): could avoid looping over all events if the caller did the
	// work to remember the relevant events (translation table construction already
	// loops over them).
	CompactSchedEventFormat ValidateFormatForCompactSched(
	const std::vector<Event>& events,
	const std::vector<Field>& common_fields) {
	using protos::pbzero::FtraceEvent;

	std::optional<CompactSchedSwitchFormat> switch_format;
	std::optional<CompactSchedWakingFormat> waking_format;
	for (const Event& event : events) {
	if (event.proto_field_id == FtraceEvent::kSchedSwitchFieldNumber) {
	switch_format = ValidateSchedSwitchFormat(event);
	}
	if (event.proto_field_id == FtraceEvent::kSchedWakingFieldNumber) {
	waking_format = ValidateSchedWakingFormat(event, common_fields);
	}
	}

	if (switch_format.has_value() && waking_format.has_value()) {
	return CompactSchedEventFormat{/format_valid=/true, switch_format.value(),
	waking_format.value()};
	} else {
	PERFETTO_ELOG("Unexpected sched_switch or sched_waking format.");
	return CompactSchedEventFormat{/format_valid=/false,
	CompactSchedSwitchFormat{},
	CompactSchedWakingFormat{}};
	}
	}

	CompactSchedEventFormat InvalidCompactSchedEventFormatForTesting() {
	return CompactSchedEventFormat{/format_valid=/false,
	CompactSchedSwitchFormat{},
	CompactSchedWakingFormat{}};
	}

	// TODO(rsavitski): find the correct place in the trace for, and method of,
	// reporting rejection of compact_sched due to compile-time assumptions not
	// holding at runtime.
	CompactSchedConfig CreateCompactSchedConfig(
	const FtraceConfig& request,
	const CompactSchedEventFormat& compact_format) {
	if (!request.compact_sched().enabled())
	return CompactSchedConfig{/enabled=/false};

	if (!compact_format.format_valid)
	return CompactSchedConfig{/enabled=/false};

	return CompactSchedConfig{/enabled=/true};
	}

	CompactSchedConfig EnabledCompactSchedConfigForTesting() {
	return CompactSchedConfig{/enabled=/true};
	}

	CompactSchedConfig DisabledCompactSchedConfigForTesting() {
	return CompactSchedConfig{/enabled=/false};
	}

	// Check size of stack-allocated bundle state.
	static_assert(sizeof(CompactSchedBuffer) <= 1 << 18,
	"CompactSchedBuffer's on-stack size excessively large.");

	void CompactSchedSwitchBuffer::Write(
	protos::pbzero::FtraceEventBundle::CompactSched* compact_out) const {
	compact_out->set_switch_timestamp(timestamp_);
	compact_out->set_switch_next_pid(next_pid_);
	compact_out->set_switch_prev_state(prev_state_);
	compact_out->set_switch_next_prio(next_prio_);
	compact_out->set_switch_next_comm_index(next_comm_index_);
	}

	void CompactSchedSwitchBuffer::Reset() {
	last_timestamp_ = 0;
	timestamp_.Reset();
	next_pid_.Reset();
	prev_state_.Reset();
	next_prio_.Reset();
	next_comm_index_.Reset();
	}

	void CompactSchedWakingBuffer::Write(
	protos::pbzero::FtraceEventBundle::CompactSched* compact_out) const {
	compact_out->set_waking_timestamp(timestamp_);
	compact_out->set_waking_pid(pid_);
	compact_out->set_waking_target_cpu(target_cpu_);
	compact_out->set_waking_prio(prio_);
	compact_out->set_waking_comm_index(comm_index_);
	compact_out->set_waking_common_flags(common_flags_);
	}

	void CompactSchedWakingBuffer::Reset() {
	last_timestamp_ = 0;
	timestamp_.Reset();
	pid_.Reset();
	target_cpu_.Reset();
	prio_.Reset();
	comm_index_.Reset();
	common_flags_.Reset();
	}

	void CommInterner::Write(
	protos::pbzero::FtraceEventBundle::CompactSched* compact_out) const {
	for (size_t i = 0; i < interned_comms_size_; i++) {
	compact_out->add_intern_table(interned_comms_[i].data(),
	interned_comms_[i].size());
	}
	}

	void CommInterner::Reset() {
	intern_buf_write_pos_ = 0;
	interned_comms_size_ = 0;
	}

	void CompactSchedBuffer::WriteAndReset(
	protos::pbzero::FtraceEventBundle* bundle) {
	if (switch_.size() > 0 \|\| waking_.size() > 0) {
	auto* compact_out = bundle->set_compact_sched();

	PERFETTO_DCHECK(interner_.interned_comms_size() > 0);
	interner_.Write(compact_out);

	if (switch_.size() > 0)
	switch_.Write(compact_out);

	if (waking_.size() > 0)
	waking_.Write(compact_out);
	}
	Reset();
	}

	void CompactSchedBuffer::Reset() {
	interner_.Reset();
	switch_.Reset();
	waking_.Reset();
	}

	} // namespace perfetto