Files
gem5/src/mem/ruby/common/WriteMask.hh
Ranganath (Bujji) Selagamsetty f6a453362f mem: Atomic ops to same address
Augmenting the DataBlock class with a change log structure to
record the effects of atomic operations on a data block and
service these changes if the atomic operations require return
values.

Although the operations are atomic, the coalescer need not
send unique memory requests for each operation. Atomic
operations within a wavefront to the same address are now
coalesced into a single memory request. The response of this
request carries all the necessary information to provide the
requesting lanes unique values as a result of their individual
atomic operations. This helps reduce contention for request
and response queues in simulation.

Previously, only the final value of the datablock after all
atomic ops to the same address was visible to the requesting
waves. This change corrects this behavior by allowing each wave
to see the effect of this individual atomic op is a return value
is necessary.

Change-Id: I639bea943afd317e45f8fa3bff7689f6b8df9395
2023-08-23 14:45:25 -05:00

267 lines
6.9 KiB
C++

/*
* Copyright (c) 2020,2021 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
* not be construed as granting a license to any other intellectual
* property including but not limited to intellectual property relating
* to a hardware implementation of the functionality of the software
* licensed hereunder. You may use the software subject to the license
* terms below provided that you ensure that this notice is replicated
* unmodified and in its entirety in all distributions of the software,
* modified or unmodified, in source code or in binary form.
*
* Copyright (c) 2012-15 Advanced Micro Devices, Inc.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are
* met: redistributions of source code must retain the above copyright
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* neither the name of the copyright holders nor the names of its
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* this software without specific prior written permission.
*
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef __MEM_RUBY_COMMON_WRITEMASK_HH__
#define __MEM_RUBY_COMMON_WRITEMASK_HH__
#include <cassert>
#include <iomanip>
#include <iostream>
#include <vector>
#include "base/amo.hh"
#include "mem/ruby/common/DataBlock.hh"
#include "mem/ruby/common/TypeDefines.hh"
namespace gem5
{
namespace ruby
{
class WriteMask
{
public:
typedef std::vector<std::pair<int, AtomicOpFunctor* >> AtomicOpVector;
WriteMask();
WriteMask(int size)
: mSize(size), mMask(size, false), mAtomic(false)
{}
WriteMask(int size, std::vector<bool> & mask)
: mSize(size), mMask(mask), mAtomic(false)
{}
WriteMask(int size, std::vector<bool> &mask, AtomicOpVector atomicOp)
: mSize(size), mMask(mask), mAtomic(true), mAtomicOp(atomicOp)
{}
~WriteMask()
{}
void
clear()
{
mMask = std::vector<bool>(mSize, false);
}
bool
test(int offset) const
{
assert(offset < mSize);
return mMask[offset];
}
void
setMask(int offset, int len, bool val = true)
{
assert(mSize >= (offset + len));
for (int i = 0; i < len; i++) {
mMask[offset + i] = val;
}
}
void
fillMask()
{
for (int i = 0; i < mSize; i++) {
mMask[i] = true;
}
}
bool
getMask(int offset, int len) const
{
bool tmp = true;
assert(mSize >= (offset + len));
for (int i = 0; i < len; i++) {
tmp = tmp & mMask.at(offset + i);
}
return tmp;
}
bool
isOverlap(const WriteMask &readMask) const
{
bool tmp = false;
assert(mSize == readMask.mSize);
for (int i = 0; i < mSize; i++) {
if (readMask.mMask.at(i)) {
tmp = tmp | mMask.at(i);
}
}
return tmp;
}
bool
containsMask(const WriteMask &readMask) const
{
bool tmp = true;
assert(mSize == readMask.mSize);
for (int i = 0; i < mSize; i++) {
if (readMask.mMask.at(i)) {
tmp = tmp & mMask.at(i);
}
}
return tmp;
}
bool isEmpty() const
{
for (int i = 0; i < mSize; i++) {
if (mMask.at(i)) {
return false;
}
}
return true;
}
bool
isFull() const
{
for (int i = 0; i < mSize; i++) {
if (!mMask.at(i)) {
return false;
}
}
return true;
}
void
andMask(const WriteMask & writeMask)
{
assert(mSize == writeMask.mSize);
for (int i = 0; i < mSize; i++) {
mMask[i] = (mMask.at(i)) && (writeMask.mMask.at(i));
}
if (writeMask.mAtomic) {
mAtomic = true;
mAtomicOp = writeMask.mAtomicOp;
}
}
void
orMask(const WriteMask & writeMask)
{
assert(mSize == writeMask.mSize);
for (int i = 0; i < mSize; i++) {
mMask[i] = (mMask.at(i)) || (writeMask.mMask.at(i));
}
if (writeMask.mAtomic) {
mAtomic = true;
mAtomicOp = writeMask.mAtomicOp;
}
}
void
setInvertedMask(const WriteMask & writeMask)
{
assert(mSize == writeMask.mSize);
for (int i = 0; i < mSize; i++) {
mMask[i] = !writeMask.mMask.at(i);
}
}
int
firstBitSet(bool val, int offset = 0) const
{
for (int i = offset; i < mSize; ++i)
if (mMask[i] == val)
return i;
return mSize;
}
int
count(int offset = 0) const
{
int count = 0;
for (int i = offset; i < mSize; ++i)
count += mMask[i];
return count;
}
void print(std::ostream& out) const;
/*
* Performs atomic operations on the data block pointed to by p. The
* atomic operations to perform are in the vector mAtomicOp. The
* effect of each atomic operation is pushed to the atomicChangeLog
* so that each individual atomic requestor may see the results of their
* specific atomic operation.
*/
void performAtomic(uint8_t * p,
std::deque<uint8_t*>& atomicChangeLog) const;
const AtomicOpVector&
getAtomicOps() const
{
return mAtomicOp;
}
void
setAtomicOps(const AtomicOpVector& atomicOps)
{
mAtomic = true;
mAtomicOp = std::move(atomicOps);
}
private:
int mSize;
std::vector<bool> mMask;
bool mAtomic;
AtomicOpVector mAtomicOp;
};
inline std::ostream&
operator<<(std::ostream& out, const WriteMask& obj)
{
obj.print(out);
out << std::flush;
return out;
}
} // namespace ruby
} // namespace gem5
#endif // __MEM_RUBY_COMMON_WRITEMASK_HH__