cb3fd715f3
This is mostly for the benefit of the LBR latency mode.
Right now, it performs no checking. If this is run on non-supported hardware, it will produce all zeroes for latency.
Differential Revision: https://reviews.llvm.org/D85254
New change: Updated lit.local.cfg to use pass the right argument to llvm-exegesis to actually request the LBR mode.
Differential Revision: https://reviews.llvm.org/D88670
61 lines
1.8 KiB
C++
61 lines
1.8 KiB
C++
//===-- X86Counter.h --------------------------------------------*- C++ -*-===//
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//
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// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
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// See https://llvm.org/LICENSE.txt for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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//
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//===----------------------------------------------------------------------===//
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///
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/// \file
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/// Perf counter that reads the LBRs for measuring the benchmarked block's
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/// throughput.
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///
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/// More info at: https://lwn.net/Articles/680985
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TOOLS_LLVM_EXEGESIS_LIB_X86_X86COUNTER_H
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#define LLVM_TOOLS_LLVM_EXEGESIS_LIB_X86_X86COUNTER_H
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#include "../PerfHelper.h"
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#include "llvm/Support/Error.h"
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// FIXME: Use appropriate wrappers for poll.h and mman.h
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// to support Windows and remove this linux-only guard.
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#if defined(__linux__) && defined(HAVE_LIBPFM) && \
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defined(LIBPFM_HAS_FIELD_CYCLES)
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namespace llvm {
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namespace exegesis {
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class X86LbrPerfEvent : public pfm::PerfEvent {
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public:
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X86LbrPerfEvent(unsigned SamplingPeriod);
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};
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class X86LbrCounter : public pfm::Counter {
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public:
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static llvm::Error checkLbrSupport();
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explicit X86LbrCounter(pfm::PerfEvent &&Event);
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virtual ~X86LbrCounter();
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void start() override;
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llvm::Expected<llvm::SmallVector<int64_t, 4>>
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readOrError(StringRef FunctionBytes) const override;
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private:
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llvm::Expected<llvm::SmallVector<int64_t, 4>>
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doReadCounter(const void *From, const void *To) const;
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void *MMappedBuffer = nullptr;
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};
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} // namespace exegesis
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} // namespace llvm
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#endif // defined(__linux__) && defined(HAVE_LIBPFM) &&
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// defined(LIBPFM_HAS_FIELD_CYCLES)
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#endif // LLVM_TOOLS_LLVM_EXEGESIS_LIB_X86_X86COUNTER_H
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