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/*
* Copyright (C) 2018 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.
*/
#ifndef INCLUDE_PERFETTO_EXT_TRACING_CORE_SHARED_MEMORY_ARBITER_H_
#define INCLUDE_PERFETTO_EXT_TRACING_CORE_SHARED_MEMORY_ARBITER_H_
#include <stddef.h>
#include <functional>
#include <memory>
#include <vector>
#include "perfetto/base/export.h"
#include "perfetto/ext/tracing/core/basic_types.h"
#include "perfetto/ext/tracing/core/tracing_service.h"
#include "perfetto/tracing/buffer_exhausted_policy.h"
namespace perfetto {
namespace base {
class TaskRunner;
}
class CommitDataRequest;
class StartupTraceWriter;
class StartupTraceWriterRegistry;
class SharedMemory;
class TraceWriter;
// Used by the Producer-side of the transport layer to vend TraceWriters
// from the SharedMemory it receives from the Service-side.
class PERFETTO_EXPORT SharedMemoryArbiter {
public:
virtual ~SharedMemoryArbiter();
// Creates a new TraceWriter and assigns it a new WriterID. The WriterID is
// written in each chunk header owned by a given TraceWriter and is used by
// the Service to reconstruct TracePackets written by the same TraceWriter.
// Returns null impl of TraceWriter if all WriterID slots are exhausted.
virtual std::unique_ptr<TraceWriter> CreateTraceWriter(
BufferID target_buffer,
BufferExhaustedPolicy buffer_exhausted_policy =
BufferExhaustedPolicy::kDefault) = 0;
// Binds the provided unbound StartupTraceWriterRegistry to the arbiter's SMB.
// Normally this happens when the perfetto service has been initialized and we
// want to rebind all the writers created in the early startup phase.
//
// All StartupTraceWriters created by the registry are bound to the arbiter
// and the given target buffer. The writers may not be bound immediately if
// they are concurrently being written to or if this method isn't called on
// the arbiter's TaskRunner. The registry will retry on the arbiter's
// TaskRunner until all writers were bound successfully.
//
// The commit of the StartupTraceWriters' locally buffered data to the SMB is
// rate limited to avoid exhausting the SMB, and may continue asynchronously
// even after all writers were bound.
//
// By calling this method, the registry's ownership is transferred to the
// arbiter. The arbiter will delete the registry once all writers were bound.
//
// TODO(eseckler): Make target buffer assignment more flexible (i.e. per
// writer). For now, embedders can use multiple registries instead.
virtual void BindStartupTraceWriterRegistry(
std::unique_ptr<StartupTraceWriterRegistry>,
BufferID target_buffer) = 0;
// Notifies the service that all data for the given FlushRequestID has been
// committed in the shared memory buffer.
virtual void NotifyFlushComplete(FlushRequestID) = 0;
// Implemented in src/core/shared_memory_arbiter_impl.cc.
// Args:
// |SharedMemory|: the shared memory buffer to use.
// |page_size|: a multiple of 4KB that defines the granularity of tracing
// pages. See tradeoff considerations in shared_memory_abi.h.
// |ProducerEndpoint|: The service's producer endpoint used e.g. to commit
// chunks and register trace writers.
// |TaskRunner|: Task runner for perfetto's main thread, which executes the
// OnPagesCompleteCallback and IPC calls to the |ProducerEndpoint|.
static std::unique_ptr<SharedMemoryArbiter> CreateInstance(
SharedMemory*,
size_t page_size,
TracingService::ProducerEndpoint*,
base::TaskRunner*);
};
} // namespace perfetto
#endif // INCLUDE_PERFETTO_EXT_TRACING_CORE_SHARED_MEMORY_ARBITER_H_
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