changeset b7bc5b1084a4 in /z/repo/gem5 details: http://repo.gem5.org/gem5?cmd=changeset;node=b7bc5b1084a4 description: arm: Add stats to table walker
This patch adds table walker stats for: - Walk events - Instruction vs Data - Page size histogram - Wait time and service time histograms - Pending requests histogram (per cycle) - measures dist. of L (p(1..) = how often busy, p(0) = how often idle) - Squashes, before starting and after completion diffstat: src/arch/arm/table_walker.cc | 186 ++++++++++++++++++++++++++++++++++++++++++- src/arch/arm/table_walker.hh | 31 +++++++ src/dev/dma_device.cc | 12 ++- src/dev/dma_device.hh | 4 +- 4 files changed, 225 insertions(+), 8 deletions(-) diffs (truncated from 476 to 300 lines): diff -r 74834c49fbbe -r b7bc5b1084a4 src/arch/arm/table_walker.cc --- a/src/arch/arm/table_walker.cc Tue Dec 23 09:31:18 2014 -0500 +++ b/src/arch/arm/table_walker.cc Tue Dec 23 09:31:18 2014 -0500 @@ -60,6 +60,8 @@ stage2Mmu(NULL), isStage2(p->is_stage2), tlb(NULL), currState(NULL), pending(false), masterId(p->sys->getMasterId(name())), numSquashable(p->num_squash_per_cycle), + pendingReqs(0), + pendingChangeTick(curTick()), doL1DescEvent(this), doL2DescEvent(this), doL0LongDescEvent(this), doL1LongDescEvent(this), doL2LongDescEvent(this), doL3LongDescEvent(this), @@ -151,6 +153,7 @@ if (params()->sys->isTimingMode() && currState) { delete currState; currState = NULL; + pendingChange(); } } @@ -170,6 +173,8 @@ bool secure, TLB::ArmTranslationType tranType) { assert(!(_functional && _timing)); + ++statWalks; + WalkerState *savedCurrState = NULL; if (!currState && !_functional) { @@ -196,10 +201,13 @@ // this fault to re-execute the faulting instruction which should clean // up everything. if (currState->vaddr_tainted == _req->getVaddr()) { + ++statSquashedBefore; return std::make_shared<ReExec>(); } } + pendingChange(); + currState->startTime = curTick(); currState->tc = _tc; currState->aarch64 = opModeIs64(currOpMode(_tc)); currState->el = currEL(_tc); @@ -261,6 +269,8 @@ currState->isFetch = (currState->mode == TLB::Execute); currState->isWrite = (currState->mode == TLB::Write); + statRequestOrigin[REQUESTED][currState->isFetch]++; + // We only do a second stage of translation if we're not secure, or in // hyp mode, the second stage MMU is enabled, and this table walker // instance is the first stage. @@ -280,6 +290,10 @@ currState->userTable = true; currState->xnTable = false; currState->pxnTable = false; + + ++statWalksLongDescriptor; + } else { + ++statWalksShortDescriptor; } if (!currState->timing) { @@ -303,8 +317,10 @@ if (pending || pendingQueue.size()) { pendingQueue.push_back(currState); currState = NULL; + pendingChange(); } else { pending = true; + pendingChange(); if (currState->aarch64) return processWalkAArch64(); else if (long_desc_format) @@ -321,6 +337,7 @@ { assert(!currState); assert(pendingQueue.size()); + pendingChange(); currState = pendingQueue.front(); ExceptionLevel target_el = EL0; @@ -372,6 +389,7 @@ (currState->transState->squashed() || te)) { pendingQueue.pop_front(); num_squashed++; + statSquashedBefore++; DPRINTF(TLB, "Squashing table walk for address %#x\n", currState->vaddr_tainted); @@ -383,6 +401,7 @@ currState->req, currState->tc, currState->mode); } else { // translate the request now that we know it will work + statWalkServiceTime.sample(curTick() - currState->startTime); tlb->translateTiming(currState->req, currState->tc, currState->transState, currState->mode); @@ -402,8 +421,9 @@ currState = NULL; } } + pendingChange(); - // if we've still got pending translations schedule more work + // if we still have pending translations, schedule more work nextWalk(tc); currState = NULL; } @@ -420,6 +440,8 @@ currState->vaddr_tainted, currState->ttbcr, mbits(currState->vaddr, 31, 32 - currState->ttbcr.n)); + statWalkWaitTime.sample(curTick() - currState->startTime); + if (currState->ttbcr.n == 0 || !mbits(currState->vaddr, 31, 32 - currState->ttbcr.n)) { DPRINTF(TLB, " - Selecting TTBR0\n"); @@ -511,6 +533,8 @@ DPRINTF(TLB, "Beginning table walk for address %#x, TTBCR: %#x\n", currState->vaddr_tainted, currState->ttbcr); + statWalkWaitTime.sample(curTick() - currState->startTime); + Request::Flags flag = 0; if (currState->isSecure) flag.set(Request::SECURE); @@ -700,6 +724,8 @@ static const GrainSize GrainMap_EL1_tg1[] = { ReservedGrain, Grain16KB, Grain4KB, Grain64KB }; + statWalkWaitTime.sample(curTick() - currState->startTime); + // Determine TTBR, table size, granule size and phys. address range Addr ttbr = 0; int tsz = 0, ps = 0; @@ -920,8 +946,8 @@ panic("Invalid table lookup level"); break; } - port.dmaAction(MemCmd::ReadReq, desc_addr, sizeof(uint64_t), event, - (uint8_t*) &currState->longDesc.data, + port.dmaAction(MemCmd::ReadReq, desc_addr, sizeof(uint64_t), + event, (uint8_t*) &currState->longDesc.data, currState->tc->getCpuPtr()->clockPeriod(), flag); DPRINTF(TLBVerbose, "Adding to walker fifo: queue size before adding: %d\n", @@ -1698,6 +1724,7 @@ if (currState->fault != NoFault) { currState->transState->finish(currState->fault, currState->req, currState->tc, currState->mode); + statWalksShortTerminatedAtLevel[0]++; pending = false; nextWalk(currState->tc); @@ -1711,9 +1738,11 @@ // delay is not set so there is no L2 to do // Don't finish the translation if a stage 2 look up is underway if (!currState->doingStage2) { + statWalkServiceTime.sample(curTick() - currState->startTime); DPRINTF(TLBVerbose, "calling translateTiming again\n"); currState->fault = tlb->translateTiming(currState->req, currState->tc, currState->transState, currState->mode); + statWalksShortTerminatedAtLevel[0]++; } pending = false; @@ -1749,13 +1778,16 @@ if (currState->fault != NoFault) { currState->transState->finish(currState->fault, currState->req, currState->tc, currState->mode); + statWalksShortTerminatedAtLevel[1]++; } else { // Don't finish the translation if a stage 2 look up is underway if (!currState->doingStage2) { + statWalkServiceTime.sample(curTick() - currState->startTime); DPRINTF(TLBVerbose, "calling translateTiming again\n"); currState->fault = tlb->translateTiming(currState->req, currState->tc, currState->transState, currState->mode); + statWalksShortTerminatedAtLevel[1]++; } } @@ -1832,9 +1864,11 @@ // Don't finish the translation if a stage 2 look up is underway if (!currState->doingStage2) { DPRINTF(TLBVerbose, "calling translateTiming again\n"); + statWalkServiceTime.sample(curTick() - currState->startTime); currState->fault = tlb->translateTiming(currState->req, currState->tc, currState->transState, currState->mode); + statWalksLongTerminatedAtLevel[(unsigned) curr_lookup_level]++; } pending = false; @@ -1906,7 +1940,7 @@ } else { if (isTiming) { port.dmaAction(MemCmd::ReadReq, descAddr, numBytes, event, data, - currState->tc->getCpuPtr()->clockPeriod(), flags); + currState->tc->getCpuPtr()->clockPeriod(),flags); if (queueIndex >= 0) { DPRINTF(TLBVerbose, "Adding to walker fifo: queue size before adding: %d\n", stateQueues[queueIndex].size()); @@ -1956,6 +1990,9 @@ else te.el = 1; + statPageSizes[pageSizeNtoStatBin(te.N)]++; + statRequestOrigin[COMPLETED][currState->isFetch]++; + // ASID has no meaning for stage 2 TLB entries, so mark all stage 2 entries // as global te.global = descriptor.global(currState) || isStage2; @@ -2024,3 +2061,144 @@ panic("Invalid lookup level conversion"); } } + +/* this method keeps track of the table walker queue's residency, so + * needs to be called whenever requests start and complete. */ +void +TableWalker::pendingChange() +{ + unsigned n = pendingQueue.size(); + if ((currState != NULL) && (currState != pendingQueue.front())) { + ++n; + } + + if (n != pendingReqs) { + Tick now = curTick(); + statPendingWalks.sample(pendingReqs, now - pendingChangeTick); + pendingReqs = n; + pendingChangeTick = now; + } +} + +uint8_t +TableWalker::pageSizeNtoStatBin(uint8_t N) +{ + /* for statPageSizes */ + switch(N) { + case 12: return 0; // 4K + case 14: return 1; // 16K (using 16K granule in v8-64) + case 16: return 2; // 64K + case 20: return 3; // 1M + case 21: return 4; // 2M-LPAE + case 24: return 5; // 16M + case 25: return 6; // 32M (using 16K granule in v8-64) + case 29: return 7; // 512M (using 64K granule in v8-64) + case 30: return 8; // 1G-LPAE + default: + panic("unknown page size"); + return 255; + } +} + +void +TableWalker::regStats() +{ + statWalks + .name(name() + ".walks") + .desc("Table walker walks requested") + ; + + statWalksShortDescriptor + .name(name() + ".walksShort") + .desc("Table walker walks initiated with short descriptors") + .flags(Stats::nozero) + ; + + statWalksLongDescriptor + .name(name() + ".walksLong") + .desc("Table walker walks initiated with long descriptors") + .flags(Stats::nozero) + ; + + statWalksShortTerminatedAtLevel + .init(2) + .name(name() + ".walksShortTerminationLevel") + .desc("Level at which table walker walks " + "with short descriptors terminate") + .flags(Stats::nozero) + ; + statWalksShortTerminatedAtLevel.subname(0, "Level1"); + statWalksShortTerminatedAtLevel.subname(1, "Level2"); + + statWalksLongTerminatedAtLevel + .init(4) + .name(name() + ".walksLongTerminationLevel") + .desc("Level at which table walker walks " + "with long descriptors terminate") + .flags(Stats::nozero) + ; + statWalksLongTerminatedAtLevel.subname(0, "Level0"); + statWalksLongTerminatedAtLevel.subname(1, "Level1"); + statWalksLongTerminatedAtLevel.subname(2, "Level2"); + statWalksLongTerminatedAtLevel.subname(3, "Level3"); + _______________________________________________ gem5-dev mailing list gem5-dev@gem5.org http://m5sim.org/mailman/listinfo/gem5-dev