74 lines
2.5 KiB
C
74 lines
2.5 KiB
C
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// Copyright (c) 2011 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#ifndef BASE_WIN_SAMPLING_PROFILER_H_
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#define BASE_WIN_SAMPLING_PROFILER_H_
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#include <vector>
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#include "base/basictypes.h"
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#include "base/time/time.h"
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#include "base/win/scoped_handle.h"
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namespace base {
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namespace win {
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// This class exposes the functionality of Window's built-in sampling profiler.
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// Each profiler instance covers a range of memory, and while the profiler is
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// running, its buckets will count the number of times the instruction counter
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// lands in the associated range of memory on a sample.
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// The sampling interval is settable, but the setting is system-wide.
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class BASE_EXPORT SamplingProfiler {
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public:
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// Create an uninitialized sampling profiler.
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SamplingProfiler();
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~SamplingProfiler();
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// Initializes the profiler to cover the memory range |start| through
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// |start| + |size|, in the process |process_handle| with bucket size
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// |2^log2_bucket_size|, |log2_bucket_size| must be in the range 2-31,
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// for bucket sizes of 4 bytes to 2 gigabytes.
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// The process handle must grant at least PROCESS_QUERY_INFORMATION.
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// The memory range should be exectuable code, like e.g. the text segment
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// of an exectuable (whether DLL or EXE).
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// Returns true on success.
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bool Initialize(HANDLE process_handle,
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void* start,
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size_t size,
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size_t log2_bucket_size);
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// Start this profiler, which must be initialized and not started.
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bool Start();
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// Stop this profiler, which must be started.
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bool Stop();
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// Get and set the sampling interval.
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// Note that this is a system-wide setting.
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static bool SetSamplingInterval(base::TimeDelta sampling_interval);
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static bool GetSamplingInterval(base::TimeDelta* sampling_interval);
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// Accessors.
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bool is_started() const { return is_started_; }
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// It is safe to read the counts in the sampling buckets at any time.
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// Note however that there's no guarantee that you'll read consistent counts
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// until the profiler has been stopped, as the counts may be updating on other
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// CPU cores.
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const std::vector<ULONG>& buckets() const { return buckets_; }
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private:
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// Handle to the corresponding kernel object.
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ScopedHandle profile_handle_;
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// True iff this profiler is started.
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bool is_started_;
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std::vector<ULONG> buckets_;
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DISALLOW_COPY_AND_ASSIGN(SamplingProfiler);
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};
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} // namespace win
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} // namespace base
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#endif // BASE_WIN_SAMPLING_PROFILER_H_
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