From: Vincentius Robby Date: Sat, 4 Aug 2007 20:05:55 +0000 (-0400) Subject: port: Implement cache for port interfaces and ranges X-Git-Tag: m5_2.0_beta4~157^2~15^2 X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=1db9e1fb8f8921a599a0b2933d682a20f97abdb8;p=gem5.git port: Implement cache for port interfaces and ranges --HG-- extra : convert_revision : d7cbec7c277fb8f4d8846203caae36ce629602d5 --- diff --git a/src/mem/bus.cc b/src/mem/bus.cc index cb359734b..9fa61a76d 100644 --- a/src/mem/bus.cc +++ b/src/mem/bus.cc @@ -84,6 +84,7 @@ Bus::deletePortRefs(Port *p) if (funcPort == bp) return; interfaces.erase(bp->getId()); + clearBusCache(); delete bp; } @@ -176,7 +177,16 @@ Bus::recvTiming(PacketPtr pkt) DPRINTF(Bus, "recvTiming: packet src %d dest %d addr 0x%x cmd %s\n", src, pkt->getDest(), pkt->getAddr(), pkt->cmdString()); - BusPort *src_port = (src == defaultId) ? defaultPort : interfaces[src]; + BusPort *src_port; + if (src == defaultId) + src_port = defaultPort; + else { + src_port = checkBusCache(src); + if (src_port == NULL) { + src_port = interfaces[src]; + updateBusCache(src, src_port); + } + } // If the bus is busy, or other devices are in line ahead of the current // one, put this device on the retry list. @@ -220,6 +230,15 @@ Bus::recvTiming(PacketPtr pkt) assert(dest >= 0 && dest < maxId); assert(dest != src); // catch infinite loops dest_port_id = dest; + if (dest_port_id == defaultId) + dest_port = defaultPort; + else { + dest_port = checkBusCache(dest); + if (dest_port == NULL) { + dest_port = interfaces[dest_port_id]; + // updateBusCache(dest_port_id, dest_port); + } + } dest_port = (dest_port_id == defaultId) ? defaultPort : interfaces[dest_port_id]; } @@ -291,9 +310,13 @@ Bus::findPort(Addr addr) /* An interval tree would be a better way to do this. --ali. */ int dest_id = -1; - PortIter i = portMap.find(RangeSize(addr,1)); - if (i != portMap.end()) - dest_id = i->second; + dest_id = checkPortCache(addr); + if (dest_id == -1) { + PortIter i = portMap.find(RangeSize(addr,1)); + if (i != portMap.end()) + dest_id = i->second; + updatePortCache(dest_id, i->first.start, i->first.end); + } // Check if this matches the default range if (dest_id == -1) { @@ -340,8 +363,16 @@ Bus::recvAtomic(PacketPtr pkt) int orig_src = pkt->getSrc(); int target_port_id = findPort(pkt->getAddr()); - Port *target_port = (target_port_id == defaultId) ? - defaultPort : interfaces[target_port_id]; + BusPort *target_port; + if (target_port_id == defaultId) + target_port = defaultPort; + else { + target_port = checkBusCache(target_port_id); + if (target_port == NULL) { + target_port = interfaces[target_port_id]; + updateBusCache(target_port_id, target_port); + } + } SnoopIter s_end = snoopPorts.end(); for (SnoopIter s_iter = snoopPorts.begin(); s_iter != s_end; s_iter++) { @@ -438,6 +469,7 @@ Bus::recvStatusChange(Port::Status status, int id) DPRINTF(BusAddrRanges, "received RangeChange from device id %d\n", id); + clearPortCache(); if (id == defaultId) { defaultRange.clear(); // Only try to update these ranges if the user set a default responder. diff --git a/src/mem/bus.hh b/src/mem/bus.hh index 06ccd4ac0..f5cad0586 100644 --- a/src/mem/bus.hh +++ b/src/mem/bus.hh @@ -180,6 +180,58 @@ class Bus : public MemObject */ int findPort(Addr addr); + // Cache for the findPort function storing recently used ports from portMap + struct PortCache { + bool valid; + int id; + Addr start; + Addr end; + }; + + PortCache portCache[3]; + + // Checks the cache and returns the id of the port that has the requested + // address within its range + inline int checkPortCache(Addr addr) { + if (portCache[0].valid && addr >= portCache[0].start && + addr < portCache[0].end) { + return portCache[0].id; + } else if (portCache[1].valid && addr >= portCache[1].start && + addr < portCache[1].end) { + return portCache[1].id; + } else if (portCache[2].valid && addr >= portCache[2].start && + addr < portCache[2].end) { + return portCache[2].id; + } + + return -1; + } + + // Clears the earliest entry of the cache and inserts a new port entry + inline void updatePortCache(short id, Addr start, Addr end) { + portCache[2].valid = portCache[1].valid; + portCache[2].id = portCache[1].id; + portCache[2].start = portCache[1].start; + portCache[2].end = portCache[1].end; + + portCache[1].valid = portCache[0].valid; + portCache[1].id = portCache[0].id; + portCache[1].start = portCache[0].start; + portCache[1].end = portCache[0].end; + + portCache[0].valid = true; + portCache[0].id = id; + portCache[0].start = start; + portCache[0].end = end; + } + + // Clears the cache. Needs to be called in constructor. + inline void clearPortCache() { + portCache[2].valid = false; + portCache[1].valid = false; + portCache[0].valid = false; + } + /** Process address range request. * @param resp addresses that we can respond to * @param snoop addresses that we would like to snoop @@ -246,6 +298,53 @@ class Bus : public MemObject int cachedBlockSize; bool cachedBlockSizeValid; + // Cache for the peer port interfaces + struct BusCache { + bool valid; + short id; + BusPort *port; + }; + + BusCache busCache[3]; + + // Checks the peer port interfaces cache for the port id and returns + // a pointer to the matching port + inline BusPort* checkBusCache(short id) { + if (busCache[0].valid && id == busCache[0].id) { + return busCache[0].port; + } else if (busCache[1].valid && id == busCache[1].id) { + return busCache[1].port; + } else if (busCache[2].valid && id == busCache[2].id) { + return busCache[2].port; + } + + return NULL; + } + + // Replaces the earliest entry in the cache with a new entry + inline void updateBusCache(short id, BusPort *port) { + busCache[2].valid = busCache[1].valid; + busCache[2].id = busCache[1].id; + busCache[2].port = busCache[1].port; + + busCache[1].valid = busCache[0].valid; + busCache[1].id = busCache[0].id; + busCache[1].port = busCache[0].port; + + busCache[0].valid = true; + busCache[0].id = id; + busCache[0].port = port; + } + + // Invalidates the cache. Needs to be called in constructor. + inline void clearBusCache() { + // memset(busCache, 0, 3 * sizeof(BusCache)); + busCache[2].valid = false; + busCache[1].valid = false; + busCache[0].valid = false; + } + + public: /** A function used to return the port associated with this bus object. */ @@ -270,6 +369,8 @@ class Bus : public MemObject fatal("Bus width must be positive\n"); if (clock <= 0) fatal("Bus clock period must be positive\n"); + clearBusCache(); + clearPortCache(); } };