From 3c608bf76535dc1f08a9563b417b5c6fadeab3ff Mon Sep 17 00:00:00 2001 From: Ali Saidi Date: Wed, 9 May 2007 18:20:24 -0400 Subject: add a backoff algorithm when nacks are received by devices add seperate response buffers and request queue sizes in bus bridge add delay to respond to a nack in the bus bridge src/dev/i8254xGBe.cc: src/dev/ide_ctrl.cc: src/dev/ns_gige.cc: src/dev/pcidev.hh: src/dev/sinic.cc: add backoff delay parameters src/dev/io_device.cc: src/dev/io_device.hh: add a backoff algorithm when nacks are received. src/mem/bridge.cc: src/mem/bridge.hh: add seperate response buffers and request queue sizes add a new parameters to specify how long before a nack in ready to go after a packet that needs to be nacked is received src/mem/cache/cache_impl.hh: assert on the src/mem/tport.cc: add a friendly assert to make sure the packet was inserted into the list --HG-- extra : convert_revision : 3595ad932015a4ce2bb72772da7850ad91bd09b1 --- src/dev/io_device.cc | 90 ++++++++++++++++++++++++++++++++++++++++++---------- 1 file changed, 74 insertions(+), 16 deletions(-) (limited to 'src/dev/io_device.cc') diff --git a/src/dev/io_device.cc b/src/dev/io_device.cc index a1285fefc..9384c4b92 100644 --- a/src/dev/io_device.cc +++ b/src/dev/io_device.cc @@ -93,7 +93,8 @@ BasicPioDevice::addressRanges(AddrRangeList &range_list) DmaPort::DmaPort(DmaDevice *dev, System *s) : Port(dev->name() + "-dmaport", dev), device(dev), sys(s), - pendingCount(0), actionInProgress(0), drainEvent(NULL) + pendingCount(0), actionInProgress(0), drainEvent(NULL), + backoffTime(0), inRetry(false), backoffEvent(this) { } bool @@ -104,12 +105,27 @@ DmaPort::recvTiming(PacketPtr pkt) if (pkt->result == Packet::Nacked) { DPRINTF(DMA, "Received nacked Pkt %#x with State: %#x Addr: %#x\n", pkt, pkt->senderState, pkt->getAddr()); + + if (backoffTime < device->minBackoffDelay) + backoffTime = device->minBackoffDelay; + else if (backoffTime < device->maxBackoffDelay) + backoffTime <<= 1; + + if (backoffEvent.scheduled()) + backoffEvent.reschedule(curTick + backoffTime); + else + backoffEvent.schedule(curTick + backoffTime); + + DPRINTF(DMA, "Backoff time set to %d ticks\n", backoffTime); + pkt->reinitNacked(); - sendDma(pkt, true); + queueDma(pkt, true); } else if (pkt->senderState) { DmaReqState *state; - DPRINTF(DMA, "Received response Pkt %#x with State: %#x Addr: %#x\n", - pkt, pkt->senderState, pkt->getAddr()); + backoffTime >>= 2; + + DPRINTF(DMA, "Received response Pkt %#x with State: %#x Addr: %#x size: %#x\n", + pkt, pkt->senderState, pkt->getAddr(), pkt->req->getSize()); state = dynamic_cast(pkt->senderState); pendingCount--; @@ -117,6 +133,7 @@ DmaPort::recvTiming(PacketPtr pkt) assert(state); state->numBytes += pkt->req->getSize(); + assert(state->totBytes >= state->numBytes); if (state->totBytes == state->numBytes) { state->completionEvent->process(); delete state; @@ -136,7 +153,8 @@ DmaPort::recvTiming(PacketPtr pkt) } DmaDevice::DmaDevice(Params *p) - : PioDevice(p), dmaPort(NULL) + : PioDevice(p), dmaPort(NULL), minBackoffDelay(p->min_backoff_delay), + maxBackoffDelay(p->max_backoff_delay) { } @@ -165,19 +183,31 @@ DmaPort::drain(Event *de) void DmaPort::recvRetry() { + assert(transmitList.size()); PacketPtr pkt = transmitList.front(); bool result = true; - while (result && transmitList.size()) { + do { DPRINTF(DMA, "Retry on Packet %#x with senderState: %#x\n", pkt, pkt->senderState); result = sendTiming(pkt); if (result) { DPRINTF(DMA, "-- Done\n"); transmitList.pop_front(); + inRetry = false; } else { + inRetry = true; DPRINTF(DMA, "-- Failed, queued\n"); } + } while (!backoffTime && result && transmitList.size()); + + if (transmitList.size() && backoffTime && !inRetry) { + DPRINTF(DMA, "Scheduling backoff for %d\n", curTick+backoffTime); + if (!backoffEvent.scheduled()) + backoffEvent.schedule(backoffTime+curTick); } + DPRINTF(DMA, "TransmitList: %d, backoffTime: %d inRetry: %d es: %d\n", + transmitList.size(), backoffTime, inRetry, + backoffEvent.scheduled()); } @@ -204,33 +234,61 @@ DmaPort::dmaAction(Packet::Command cmd, Addr addr, int size, Event *event, assert(pendingCount >= 0); pendingCount++; - sendDma(pkt); + queueDma(pkt); } } +void +DmaPort::queueDma(PacketPtr pkt, bool front) +{ + + if (front) + transmitList.push_front(pkt); + else + transmitList.push_back(pkt); + sendDma(); +} + void -DmaPort::sendDma(PacketPtr pkt, bool front) +DmaPort::sendDma() { // some kind of selction between access methods // more work is going to have to be done to make // switching actually work + assert(transmitList.size()); + PacketPtr pkt = transmitList.front(); System::MemoryMode state = sys->getMemoryMode(); if (state == System::Timing) { + if (backoffEvent.scheduled() || inRetry) { + DPRINTF(DMA, "Can't send immediately, waiting for retry or backoff timer\n"); + return; + } + DPRINTF(DMA, "Attempting to send Packet %#x with addr: %#x\n", pkt, pkt->getAddr()); - if (transmitList.size() || !sendTiming(pkt)) { - if (front) - transmitList.push_front(pkt); - else - transmitList.push_back(pkt); - DPRINTF(DMA, "-- Failed: queued\n"); - } else { - DPRINTF(DMA, "-- Done\n"); + + bool result; + do { + result = sendTiming(pkt); + if (result) { + transmitList.pop_front(); + DPRINTF(DMA, "-- Done\n"); + } else { + inRetry = true; + DPRINTF(DMA, "-- Failed: queued\n"); + } + } while (result && !backoffTime && transmitList.size()); + + if (transmitList.size() && backoffTime && !inRetry && + !backoffEvent.scheduled()) { + backoffEvent.schedule(backoffTime+curTick); } } else if (state == System::Atomic) { + transmitList.pop_front(); + Tick lat; lat = sendAtomic(pkt); assert(pkt->senderState); -- cgit v1.2.3