/*
- * Copyright (c) 2012-2013, 2015-2016 ARM Limited
+ * Copyright (c) 2012-2013, 2015-2018 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
#include <string>
#include <vector>
-#include "base/misc.hh"
+#include "base/logging.hh"
#include "base/types.hh"
#include "debug/Cache.hh"
#include "mem/cache/cache.hh"
MSHR::MSHR() : downstreamPending(false),
pendingModified(false),
postInvalidate(false), postDowngrade(false),
- isForward(false), allocOnFill(false)
+ isForward(false)
{
}
MSHR::TargetList::TargetList()
- : needsWritable(false), hasUpgrade(false)
+ : needsWritable(false), hasUpgrade(false), allocOnFill(false)
{}
-inline void
-MSHR::TargetList::add(PacketPtr pkt, Tick readyTime,
- Counter order, Target::Source source, bool markPending)
+void
+MSHR::TargetList::updateFlags(PacketPtr pkt, Target::Source source,
+ bool alloc_on_fill)
{
if (source != Target::FromSnoop) {
if (pkt->needsWritable()) {
if (pkt->isUpgrade() || pkt->cmd == MemCmd::StoreCondReq) {
hasUpgrade = true;
}
+
+ // potentially re-evaluate whether we should allocate on a fill or
+ // not
+ allocOnFill = allocOnFill || alloc_on_fill;
}
+}
+void
+MSHR::TargetList::populateFlags()
+{
+ resetFlags();
+ for (auto& t: *this) {
+ updateFlags(t.pkt, t.source, t.allocOnFill);
+ }
+}
+
+inline void
+MSHR::TargetList::add(PacketPtr pkt, Tick readyTime,
+ Counter order, Target::Source source, bool markPending,
+ bool alloc_on_fill)
+{
+ updateFlags(pkt, source, alloc_on_fill);
if (markPending) {
// Iterate over the SenderState stack and see if we find
// an MSHR entry. If we do, set the downstreamPending
}
}
- emplace_back(pkt, readyTime, order, source, markPending);
+ emplace_back(pkt, readyTime, order, source, markPending, alloc_on_fill);
}
if (mshr != nullptr) {
mshr->clearDownstreamPending();
}
+ t.markedPending = false;
}
}
}
}
ccprintf(os, "%s%s: ", prefix, s);
t.pkt->print(os, verbosity, "");
+ ccprintf(os, "\n");
}
}
order = _order;
assert(target);
isForward = false;
- allocOnFill = alloc_on_fill;
_isUncacheable = target->req->isUncacheable();
inService = false;
downstreamPending = false;
// snoop (mem-side request), so set source according to request here
Target::Source source = (target->cmd == MemCmd::HardPFReq) ?
Target::FromPrefetcher : Target::FromCPU;
- targets.add(target, when_ready, _order, source, true);
+ targets.add(target, when_ready, _order, source, true, alloc_on_fill);
assert(deferredTargets.isReset());
}
// have targets addded if originally allocated uncacheable
assert(!_isUncacheable);
- // potentially re-evaluate whether we should allocate on a fill or
- // not
- allocOnFill = allocOnFill || alloc_on_fill;
-
// if there's a request already in service for this MSHR, we will
// have to defer the new target until after the response if any of
// the following are true:
// - there are other targets already deferred
// - there's a pending invalidate to be applied after the response
// comes back (but before this target is processed)
+ // - the MSHR's first (and only) non-deferred target is a cache
+ // maintenance packet
+ // - the new target is a cache maintenance packet (this is probably
+ // overly conservative but certainly safe)
// - this target requires a writable block and either we're not
// getting a writable block back or we have already snooped
// another read request that will downgrade our writable block
// to non-writable (Shared or Owned)
- if (inService &&
- (!deferredTargets.empty() || hasPostInvalidate() ||
- (pkt->needsWritable() &&
- (!isPendingModified() || hasPostDowngrade() || isForward)))) {
+ PacketPtr tgt_pkt = targets.front().pkt;
+ if (pkt->req->isCacheMaintenance() ||
+ tgt_pkt->req->isCacheMaintenance() ||
+ !deferredTargets.empty() ||
+ (inService &&
+ (hasPostInvalidate() ||
+ (pkt->needsWritable() &&
+ (!isPendingModified() || hasPostDowngrade() || isForward))))) {
// need to put on deferred list
- if (hasPostInvalidate())
+ if (inService && hasPostInvalidate())
replaceUpgrade(pkt);
- deferredTargets.add(pkt, whenReady, _order, Target::FromCPU, true);
+ deferredTargets.add(pkt, whenReady, _order, Target::FromCPU, true,
+ alloc_on_fill);
} else {
// No request outstanding, or still OK to append to
// outstanding request: append to regular target list. Only
// mark pending if current request hasn't been issued yet
// (isn't in service).
- targets.add(pkt, whenReady, _order, Target::FromCPU, !inService);
+ targets.add(pkt, whenReady, _order, Target::FromCPU, !inService,
+ alloc_on_fill);
}
}
bool
MSHR::handleSnoop(PacketPtr pkt, Counter _order)
{
- DPRINTF(Cache, "%s for %s addr %#llx size %d\n", __func__,
- pkt->cmdString(), pkt->getAddr(), pkt->getSize());
+ DPRINTF(Cache, "%s for %s\n", __func__, pkt->print());
// when we snoop packets the needsWritable and isInvalidate flags
// should always be the same, however, this assumes that we never
// snoop writes as they are currently not marked as invalidations
- panic_if(pkt->needsWritable() != pkt->isInvalidate(),
- "%s got snoop %s to addr %#llx where needsWritable, "
- "does not match isInvalidate", name(), pkt->cmdString(),
- pkt->getAddr());
+ panic_if((pkt->needsWritable() != pkt->isInvalidate()) &&
+ !pkt->req->isCacheMaintenance(),
+ "%s got snoop %s where needsWritable, "
+ "does not match isInvalidate", name(), pkt->print());
if (!inService || (pkt->isExpressSnoop() && downstreamPending)) {
// Request has not been issued yet, or it's been issued
// That is, even though the upper-level cache got out on its
// local bus first, some other invalidating transaction
// reached the global bus before the upgrade did.
- if (pkt->needsWritable()) {
+ if (pkt->needsWritable() || pkt->req->isCacheInvalidate()) {
targets.replaceUpgrades();
deferredTargets.replaceUpgrades();
}
// From here on down, the request issued by this MSHR logically
// precedes the request we're snooping.
- if (pkt->needsWritable()) {
+ if (pkt->needsWritable() || pkt->req->isCacheInvalidate()) {
// snooped request still precedes the re-request we'll have to
// issue for deferred targets, if any...
deferredTargets.replaceUpgrades();
}
- if (hasPostInvalidate()) {
- // a prior snoop has already appended an invalidation, so
- // logically we don't have the block anymore; no need for
- // further snooping.
+ PacketPtr tgt_pkt = targets.front().pkt;
+ if (hasPostInvalidate() || tgt_pkt->req->isCacheInvalidate()) {
+ // a prior snoop has already appended an invalidation or a
+ // cache invalidation operation is in progress, so logically
+ // we don't have the block anymore; no need for further
+ // snooping.
return true;
}
// Start by determining if we will eventually respond or not,
// matching the conditions checked in Cache::handleSnoop
bool will_respond = isPendingModified() && pkt->needsResponse() &&
- pkt->cmd != MemCmd::InvalidateReq;
+ !pkt->isClean();
// The packet we are snooping may be deleted by the time we
// actually process the target, and we consequently need to
// the packet and the request as part of handling the deferred
// snoop.
PacketPtr cp_pkt = will_respond ? new Packet(pkt, true, true) :
- new Packet(new Request(*pkt->req), pkt->cmd);
+ new Packet(new Request(*pkt->req), pkt->cmd, blkSize, pkt->id);
if (will_respond) {
// we are the ordering point, and will consequently
// recipient does not care there is no harm in doing so
}
targets.add(cp_pkt, curTick(), _order, Target::FromSnoop,
- downstreamPending && targets.needsWritable);
+ downstreamPending && targets.needsWritable, false);
- if (pkt->needsWritable()) {
+ if (pkt->needsWritable() || pkt->isInvalidate()) {
// This transaction will take away our pending copy
postInvalidate = true;
}
+
+ if (isPendingModified() && pkt->isClean()) {
+ pkt->setSatisfied();
+ }
}
if (!pkt->needsWritable() && !pkt->req->isUncacheable()) {
return true;
}
+MSHR::TargetList
+MSHR::extractServiceableTargets(PacketPtr pkt)
+{
+ TargetList ready_targets;
+ // If the downstream MSHR got an invalidation request then we only
+ // service the first of the FromCPU targets and any other
+ // non-FromCPU target. This way the remaining FromCPU targets
+ // issue a new request and get a fresh copy of the block and we
+ // avoid memory consistency violations.
+ if (pkt->cmd == MemCmd::ReadRespWithInvalidate) {
+ auto it = targets.begin();
+ assert((it->source == Target::FromCPU) ||
+ (it->source == Target::FromPrefetcher));
+ ready_targets.push_back(*it);
+ it = targets.erase(it);
+ while (it != targets.end()) {
+ if (it->source == Target::FromCPU) {
+ it++;
+ } else {
+ assert(it->source == Target::FromSnoop);
+ ready_targets.push_back(*it);
+ it = targets.erase(it);
+ }
+ }
+ ready_targets.populateFlags();
+ } else {
+ std::swap(ready_targets, targets);
+ }
+ targets.populateFlags();
+
+ return ready_targets;
+}
bool
MSHR::promoteDeferredTargets()
{
- assert(targets.empty());
- if (deferredTargets.empty()) {
+ if (targets.empty() && deferredTargets.empty()) {
+ // nothing to promote
return false;
}
- // swap targets & deferredTargets lists
- std::swap(targets, deferredTargets);
-
- // clear deferredTargets flags
- deferredTargets.resetFlags();
+ // the deferred targets can be generally promoted unless they
+ // contain a cache maintenance request
+
+ // find the first target that is a cache maintenance request
+ auto it = std::find_if(deferredTargets.begin(), deferredTargets.end(),
+ [](MSHR::Target &t) {
+ return t.pkt->req->isCacheMaintenance();
+ });
+ if (it == deferredTargets.begin()) {
+ // if the first deferred target is a cache maintenance packet
+ // then we can promote provided the targets list is empty and
+ // we can service it on its own
+ if (targets.empty()) {
+ targets.splice(targets.end(), deferredTargets, it);
+ }
+ } else {
+ // if a cache maintenance operation exists, we promote all the
+ // deferred targets that precede it, or all deferred targets
+ // otherwise
+ targets.splice(targets.end(), deferredTargets,
+ deferredTargets.begin(), it);
+ }
+ deferredTargets.populateFlags();
+ targets.populateFlags();
order = targets.front().order;
readyTime = std::max(curTick(), targets.front().readyTime);
prefix, blkAddr, blkAddr + blkSize - 1,
isSecure ? "s" : "ns",
isForward ? "Forward" : "",
- allocOnFill ? "AllocOnFill" : "",
+ allocOnFill() ? "AllocOnFill" : "",
needsWritable() ? "Wrtbl" : "",
_isUncacheable ? "Unc" : "",
inService ? "InSvc" : "",
projects / gem5.git / blobdiff