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// Copyright 2017 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <cstddef>
#include <cstdint>
namespace perfmon {
// struct to export |LastBranchRecord| as a "blob" in the trace
// format. A problem that we need to solve is giving the reader a way to match
// last branch records with their originating event. The way we do this is to
// add the cpu and timestamp to the data.
struct LastBranchRecordBlob {
// The cpu this event was captured on.
uint16_t cpu;
// The number of entries in |branches|.
uint16_t num_branches;
// For alignment purposes, and future-proofing. Always zero.
uint32_t reserved;
// The time the record was obtained, in "trace ticks".
uint64_t event_time;
// The address space id (e.g., CR3) at the time data was collected.
// This is not necessarily the aspace id of each branch. S/W will need to
// determine from the branch addresses how far back aspace is valid.
uint64_t aspace;
// Set of branches, in reverse chronological order.
struct LastBranchEntry {
uint64_t from;
uint64_t to;
// Processor-provided details on this branch.
// bits 0-15: Elapsed time since the last branch. Zero if unknown.
// The unit of measurement is processor-specific.
// bit 16: Non-zero if branch was mispredicted.
uint64_t info;
} branches[];
static inline size_t LastBranchRecordBlobSize(uint16_t num_branches) {
return (sizeof(LastBranchRecordBlob) +
(num_branches * sizeof(LastBranchRecordBlob::LastBranchEntry)));
} // namespace perfmon