/*
- * Copyright (c) 2012-2013, 2015-2016 ARM Limited
+ * Copyright (c) 2012-2013, 2015-2016, 2018 ARM Limited
* All rights reserved.
*
* The license below extends only to copyright in the software and shall
#ifndef __MEM_CACHE_MSHR_HH__
#define __MEM_CACHE_MSHR_HH__
+#include <cassert>
+#include <iosfwd>
#include <list>
+#include <string>
#include "base/printable.hh"
+#include "base/types.hh"
#include "mem/cache/queue_entry.hh"
+#include "mem/packet.hh"
+#include "sim/core.hh"
-class Cache;
+class BaseCache;
/**
* Miss Status and handling Register. This class keeps all the information
const Counter order; //!< Global order (for memory consistency mgmt)
const PacketPtr pkt; //!< Pending request packet.
const Source source; //!< Request from cpu, memory, or prefetcher?
- const bool markedPending; //!< Did we mark upstream MSHR
- //!< as downstreamPending?
+
+ /**
+ * We use this flag to track whether we have cleared the
+ * downstreamPending flag for the MSHR of the cache above
+ * where this packet originates from and guard noninitial
+ * attempts to clear it.
+ *
+ * The flag markedPending needs to be updated when the
+ * TargetList is in service which can be:
+ * 1) during the Target instantiation if the MSHR is in
+ * service and the target is not deferred,
+ * 2) when the MSHR becomes in service if the target is not
+ * deferred,
+ * 3) or when the TargetList is promoted (deferredTargets ->
+ * targets).
+ */
+ bool markedPending;
+
const bool allocOnFill; //!< Should the response servicing this
//!< target list allocate in the cache?
bool hasUpgrade;
/** Set when the response should allocate on fill */
bool allocOnFill;
+ /**
+ * Determine whether there was at least one non-snooping
+ * target coming from another cache.
+ */
+ bool hasFromCache;
TargetList();
void updateFlags(PacketPtr pkt, Target::Source source,
bool alloc_on_fill);
- void resetFlags() { needsWritable = hasUpgrade = allocOnFill = false; }
+ void resetFlags() {
+ needsWritable = false;
+ hasUpgrade = false;
+ allocOnFill = false;
+ hasFromCache = false;
+ }
/**
* Goes through the list of targets and uses them to populate
* values.
*/
bool isReset() const {
- return !needsWritable && !hasUpgrade && !allocOnFill;
+ return !needsWritable && !hasUpgrade && !allocOnFill &&
+ !hasFromCache;
}
/**
void replaceUpgrades();
void clearDownstreamPending();
- bool checkFunctional(PacketPtr pkt);
+ void clearDownstreamPending(iterator begin, iterator end);
+ bool trySatisfyFunctional(PacketPtr pkt);
void print(std::ostream &os, int verbosity,
const std::string &prefix) const;
};
/** True if we need to get a writable copy of the block. */
bool needsWritable() const { return targets.needsWritable; }
+ bool isCleaning() const {
+ PacketPtr pkt = targets.front().pkt;
+ return pkt->isClean();
+ }
+
bool isPendingModified() const {
assert(inService); return pendingModified;
}
assert(inService); return postDowngrade;
}
- bool sendPacket(Cache &cache);
+ bool sendPacket(BaseCache &cache);
bool allocOnFill() const {
return targets.allocOnFill;
}
+
+ /**
+ * Determine if there are non-deferred requests from other caches
+ *
+ * @return true if any of the targets is from another cache
+ */
+ bool hasFromCache() const {
+ return targets.hasFromCache;
+ }
+
private:
+ /**
+ * Promotes deferred targets that satisfy a predicate
+ *
+ * Deferred targets are promoted to the target list if they
+ * satisfy a given condition. The operation stops at the first
+ * deferred target that doesn't satisfy the condition.
+ *
+ * @param pred A condition on a Target
+ */
+ void promoteIf(const std::function<bool (Target &)>& pred);
/**
* Pointer to this MSHR on the ready list.
int getNumTargets() const
{ return targets.size() + deferredTargets.size(); }
+ /**
+ * Extracts the subset of the targets that can be serviced given a
+ * received response. This function returns the targets list
+ * unless the response is a ReadRespWithInvalidate. The
+ * ReadRespWithInvalidate is only invalidating response that its
+ * invalidation was not expected when the request (a
+ * ReadSharedReq) was sent out. For ReadRespWithInvalidate we can
+ * safely service only the first FromCPU target and all FromSnoop
+ * targets (inform all snoopers that we no longer have the block).
+ *
+ * @param pkt The response from the downstream memory
+ */
+ TargetList extractServiceableTargets(PacketPtr pkt);
+
/**
* Returns true if there are targets left.
* @return true if there are targets
bool promoteDeferredTargets();
+ /**
+ * Promotes deferred targets that do not require writable
+ *
+ * Move targets from the deferred targets list to the target list
+ * starting from the first deferred target until the first target
+ * that is a cache maintenance operation or needs a writable copy
+ * of the block
+ */
+ void promoteReadable();
+
+ /**
+ * Promotes deferred targets that do not require writable
+ *
+ * Requests in the deferred target list are moved to the target
+ * list up until the first target that is a cache maintenance
+ * operation or needs a writable copy of the block
+ */
void promoteWritable();
- bool checkFunctional(PacketPtr pkt);
+ bool trySatisfyFunctional(PacketPtr pkt);
/**
* Prints the contents of this MSHR for debugging.
projects / gem5.git / blobdiff