1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373
|
//===--------------------- ResourceManager.cpp ------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
/// \file
///
/// The classes here represent processor resource units and their management
/// strategy. These classes are managed by the Scheduler.
///
//===----------------------------------------------------------------------===//
#include "llvm/MCA/HardwareUnits/ResourceManager.h"
#include "llvm/MCA/Support.h"
#include "llvm/Support/Debug.h"
#include "llvm/Support/raw_ostream.h"
namespace llvm {
namespace mca {
#define DEBUG_TYPE "llvm-mca"
ResourceStrategy::~ResourceStrategy() = default;
static uint64_t selectImpl(uint64_t CandidateMask,
uint64_t &NextInSequenceMask) {
// The upper bit set in CandidateMask identifies our next candidate resource.
CandidateMask = 1ULL << getResourceStateIndex(CandidateMask);
NextInSequenceMask &= (CandidateMask | (CandidateMask - 1));
return CandidateMask;
}
uint64_t DefaultResourceStrategy::select(uint64_t ReadyMask) {
// This method assumes that ReadyMask cannot be zero.
uint64_t CandidateMask = ReadyMask & NextInSequenceMask;
if (CandidateMask)
return selectImpl(CandidateMask, NextInSequenceMask);
NextInSequenceMask = ResourceUnitMask ^ RemovedFromNextInSequence;
RemovedFromNextInSequence = 0;
CandidateMask = ReadyMask & NextInSequenceMask;
if (CandidateMask)
return selectImpl(CandidateMask, NextInSequenceMask);
NextInSequenceMask = ResourceUnitMask;
CandidateMask = ReadyMask & NextInSequenceMask;
return selectImpl(CandidateMask, NextInSequenceMask);
}
void DefaultResourceStrategy::used(uint64_t Mask) {
if (Mask > NextInSequenceMask) {
RemovedFromNextInSequence |= Mask;
return;
}
NextInSequenceMask &= (~Mask);
if (NextInSequenceMask)
return;
NextInSequenceMask = ResourceUnitMask ^ RemovedFromNextInSequence;
RemovedFromNextInSequence = 0;
}
ResourceState::ResourceState(const MCProcResourceDesc &Desc, unsigned Index,
uint64_t Mask)
: ProcResourceDescIndex(Index), ResourceMask(Mask),
BufferSize(Desc.BufferSize), IsAGroup(countPopulation(ResourceMask) > 1) {
if (IsAGroup) {
ResourceSizeMask =
ResourceMask ^ 1ULL << getResourceStateIndex(ResourceMask);
} else {
ResourceSizeMask = (1ULL << Desc.NumUnits) - 1;
}
ReadyMask = ResourceSizeMask;
AvailableSlots = BufferSize == -1 ? 0U : static_cast<unsigned>(BufferSize);
Unavailable = false;
}
bool ResourceState::isReady(unsigned NumUnits) const {
return (!isReserved() || isADispatchHazard()) &&
countPopulation(ReadyMask) >= NumUnits;
}
ResourceStateEvent ResourceState::isBufferAvailable() const {
if (isADispatchHazard() && isReserved())
return RS_RESERVED;
if (!isBuffered() || AvailableSlots)
return RS_BUFFER_AVAILABLE;
return RS_BUFFER_UNAVAILABLE;
}
#ifndef NDEBUG
void ResourceState::dump() const {
dbgs() << "MASK=" << format_hex(ResourceMask, 16)
<< ", SZMASK=" << format_hex(ResourceSizeMask, 16)
<< ", RDYMASK=" << format_hex(ReadyMask, 16)
<< ", BufferSize=" << BufferSize
<< ", AvailableSlots=" << AvailableSlots
<< ", Reserved=" << Unavailable << '\n';
}
#endif
static std::unique_ptr<ResourceStrategy>
getStrategyFor(const ResourceState &RS) {
if (RS.isAResourceGroup() || RS.getNumUnits() > 1)
return std::make_unique<DefaultResourceStrategy>(RS.getReadyMask());
return std::unique_ptr<ResourceStrategy>(nullptr);
}
ResourceManager::ResourceManager(const MCSchedModel &SM)
: Resources(SM.getNumProcResourceKinds() - 1),
Strategies(SM.getNumProcResourceKinds() - 1),
Resource2Groups(SM.getNumProcResourceKinds() - 1, 0),
ProcResID2Mask(SM.getNumProcResourceKinds(), 0),
ResIndex2ProcResID(SM.getNumProcResourceKinds() - 1, 0),
ProcResUnitMask(0), ReservedResourceGroups(0), AvailableBuffers(~0ULL),
ReservedBuffers(0) {
computeProcResourceMasks(SM, ProcResID2Mask);
// initialize vector ResIndex2ProcResID.
for (unsigned I = 1, E = SM.getNumProcResourceKinds(); I < E; ++I) {
unsigned Index = getResourceStateIndex(ProcResID2Mask[I]);
ResIndex2ProcResID[Index] = I;
}
for (unsigned I = 1, E = SM.getNumProcResourceKinds(); I < E; ++I) {
uint64_t Mask = ProcResID2Mask[I];
unsigned Index = getResourceStateIndex(Mask);
Resources[Index] =
std::make_unique<ResourceState>(*SM.getProcResource(I), I, Mask);
Strategies[Index] = getStrategyFor(*Resources[Index]);
}
for (unsigned I = 1, E = SM.getNumProcResourceKinds(); I < E; ++I) {
uint64_t Mask = ProcResID2Mask[I];
unsigned Index = getResourceStateIndex(Mask);
const ResourceState &RS = *Resources[Index];
if (!RS.isAResourceGroup()) {
ProcResUnitMask |= Mask;
continue;
}
uint64_t GroupMaskIdx = 1ULL << Index;
Mask -= GroupMaskIdx;
while (Mask) {
// Extract lowest set isolated bit.
uint64_t Unit = Mask & (-Mask);
unsigned IndexUnit = getResourceStateIndex(Unit);
Resource2Groups[IndexUnit] |= GroupMaskIdx;
Mask ^= Unit;
}
}
AvailableProcResUnits = ProcResUnitMask;
}
void ResourceManager::setCustomStrategyImpl(std::unique_ptr<ResourceStrategy> S,
uint64_t ResourceMask) {
unsigned Index = getResourceStateIndex(ResourceMask);
assert(Index < Resources.size() && "Invalid processor resource index!");
assert(S && "Unexpected null strategy in input!");
Strategies[Index] = std::move(S);
}
unsigned ResourceManager::resolveResourceMask(uint64_t Mask) const {
return ResIndex2ProcResID[getResourceStateIndex(Mask)];
}
unsigned ResourceManager::getNumUnits(uint64_t ResourceID) const {
return Resources[getResourceStateIndex(ResourceID)]->getNumUnits();
}
// Returns the actual resource consumed by this Use.
// First, is the primary resource ID.
// Second, is the specific sub-resource ID.
ResourceRef ResourceManager::selectPipe(uint64_t ResourceID) {
unsigned Index = getResourceStateIndex(ResourceID);
assert(Index < Resources.size() && "Invalid resource use!");
ResourceState &RS = *Resources[Index];
assert(RS.isReady() && "No available units to select!");
// Special case where RS is not a group, and it only declares a single
// resource unit.
if (!RS.isAResourceGroup() && RS.getNumUnits() == 1)
return std::make_pair(ResourceID, RS.getReadyMask());
uint64_t SubResourceID = Strategies[Index]->select(RS.getReadyMask());
if (RS.isAResourceGroup())
return selectPipe(SubResourceID);
return std::make_pair(ResourceID, SubResourceID);
}
void ResourceManager::use(const ResourceRef &RR) {
// Mark the sub-resource referenced by RR as used.
unsigned RSID = getResourceStateIndex(RR.first);
ResourceState &RS = *Resources[RSID];
RS.markSubResourceAsUsed(RR.second);
// Remember to update the resource strategy for non-group resources with
// multiple units.
if (RS.getNumUnits() > 1)
Strategies[RSID]->used(RR.second);
// If there are still available units in RR.first,
// then we are done.
if (RS.isReady())
return;
AvailableProcResUnits ^= RR.first;
// Notify groups that RR.first is no longer available.
uint64_t Users = Resource2Groups[RSID];
while (Users) {
// Extract lowest set isolated bit.
unsigned GroupIndex = getResourceStateIndex(Users & (-Users));
ResourceState &CurrentUser = *Resources[GroupIndex];
CurrentUser.markSubResourceAsUsed(RR.first);
Strategies[GroupIndex]->used(RR.first);
// Reset lowest set bit.
Users &= Users - 1;
}
}
void ResourceManager::release(const ResourceRef &RR) {
unsigned RSID = getResourceStateIndex(RR.first);
ResourceState &RS = *Resources[RSID];
bool WasFullyUsed = !RS.isReady();
RS.releaseSubResource(RR.second);
if (!WasFullyUsed)
return;
AvailableProcResUnits ^= RR.first;
// Notify groups that RR.first is now available again.
uint64_t Users = Resource2Groups[RSID];
while (Users) {
unsigned GroupIndex = getResourceStateIndex(Users & (-Users));
ResourceState &CurrentUser = *Resources[GroupIndex];
CurrentUser.releaseSubResource(RR.first);
Users &= Users - 1;
}
}
ResourceStateEvent
ResourceManager::canBeDispatched(uint64_t ConsumedBuffers) const {
if (ConsumedBuffers & ReservedBuffers)
return ResourceStateEvent::RS_RESERVED;
if (ConsumedBuffers & (~AvailableBuffers))
return ResourceStateEvent::RS_BUFFER_UNAVAILABLE;
return ResourceStateEvent::RS_BUFFER_AVAILABLE;
}
void ResourceManager::reserveBuffers(uint64_t ConsumedBuffers) {
while (ConsumedBuffers) {
uint64_t CurrentBuffer = ConsumedBuffers & (-ConsumedBuffers);
ResourceState &RS = *Resources[getResourceStateIndex(CurrentBuffer)];
ConsumedBuffers ^= CurrentBuffer;
assert(RS.isBufferAvailable() == ResourceStateEvent::RS_BUFFER_AVAILABLE);
if (!RS.reserveBuffer())
AvailableBuffers ^= CurrentBuffer;
if (RS.isADispatchHazard()) {
// Reserve this buffer now, and release it once pipeline resources
// consumed by the instruction become available again.
// We do this to simulate an in-order dispatch/issue of instructions.
ReservedBuffers ^= CurrentBuffer;
}
}
}
void ResourceManager::releaseBuffers(uint64_t ConsumedBuffers) {
AvailableBuffers |= ConsumedBuffers;
while (ConsumedBuffers) {
uint64_t CurrentBuffer = ConsumedBuffers & (-ConsumedBuffers);
ResourceState &RS = *Resources[getResourceStateIndex(CurrentBuffer)];
ConsumedBuffers ^= CurrentBuffer;
RS.releaseBuffer();
// Do not unreserve dispatch hazard resource buffers. Wait until all
// pipeline resources have been freed too.
}
}
uint64_t ResourceManager::checkAvailability(const InstrDesc &Desc) const {
uint64_t BusyResourceMask = 0;
for (const std::pair<uint64_t, ResourceUsage> &E : Desc.Resources) {
unsigned NumUnits = E.second.isReserved() ? 0U : E.second.NumUnits;
unsigned Index = getResourceStateIndex(E.first);
if (!Resources[Index]->isReady(NumUnits))
BusyResourceMask |= E.first;
}
uint64_t ImplicitUses = Desc.ImplicitlyUsedProcResUnits;
while (ImplicitUses) {
uint64_t Use = ImplicitUses & -ImplicitUses;
ImplicitUses ^= Use;
unsigned Index = getResourceStateIndex(Use);
if (!Resources[Index]->isReady(/* NumUnits */ 1))
BusyResourceMask |= Index;
}
BusyResourceMask &= ProcResUnitMask;
if (BusyResourceMask)
return BusyResourceMask;
return Desc.UsedProcResGroups & ReservedResourceGroups;
}
void ResourceManager::issueInstruction(
const InstrDesc &Desc,
SmallVectorImpl<std::pair<ResourceRef, ResourceCycles>> &Pipes) {
for (const std::pair<uint64_t, ResourceUsage> &R : Desc.Resources) {
const CycleSegment &CS = R.second.CS;
if (!CS.size()) {
releaseResource(R.first);
continue;
}
assert(CS.begin() == 0 && "Invalid {Start, End} cycles!");
if (!R.second.isReserved()) {
ResourceRef Pipe = selectPipe(R.first);
use(Pipe);
BusyResources[Pipe] += CS.size();
Pipes.emplace_back(std::pair<ResourceRef, ResourceCycles>(
Pipe, ResourceCycles(CS.size())));
} else {
assert((countPopulation(R.first) > 1) && "Expected a group!");
// Mark this group as reserved.
assert(R.second.isReserved());
reserveResource(R.first);
BusyResources[ResourceRef(R.first, R.first)] += CS.size();
}
}
}
void ResourceManager::cycleEvent(SmallVectorImpl<ResourceRef> &ResourcesFreed) {
for (std::pair<ResourceRef, unsigned> &BR : BusyResources) {
if (BR.second)
BR.second--;
if (!BR.second) {
// Release this resource.
const ResourceRef &RR = BR.first;
if (countPopulation(RR.first) == 1)
release(RR);
releaseResource(RR.first);
ResourcesFreed.push_back(RR);
}
}
for (const ResourceRef &RF : ResourcesFreed)
BusyResources.erase(RF);
}
void ResourceManager::reserveResource(uint64_t ResourceID) {
const unsigned Index = getResourceStateIndex(ResourceID);
ResourceState &Resource = *Resources[Index];
assert(Resource.isAResourceGroup() && !Resource.isReserved() &&
"Unexpected resource state found!");
Resource.setReserved();
ReservedResourceGroups ^= 1ULL << Index;
}
void ResourceManager::releaseResource(uint64_t ResourceID) {
const unsigned Index = getResourceStateIndex(ResourceID);
ResourceState &Resource = *Resources[Index];
Resource.clearReserved();
if (Resource.isAResourceGroup())
ReservedResourceGroups ^= 1ULL << Index;
// Now it is safe to release dispatch/issue resources.
if (Resource.isADispatchHazard())
ReservedBuffers ^= 1ULL << Index;
}
} // namespace mca
} // namespace llvm
|