diff options
Diffstat (limited to 'src')
-rwxr-xr-x | src/mem/snoop_filter.cc | 54 |
1 files changed, 25 insertions, 29 deletions
diff --git a/src/mem/snoop_filter.cc b/src/mem/snoop_filter.cc index 9b005cbc5..d6e74cf0a 100755 --- a/src/mem/snoop_filter.cc +++ b/src/mem/snoop_filter.cc @@ -174,12 +174,6 @@ SnoopFilter::lookupSnoop(const Packet* cpkt) assert(cpkt->isRequest()); - // Broadcast / filter upward snoops - const bool filter_upward = true; // @todo: Make configurable - - if (!filter_upward) - return snoopAll(lookupLatency); - Addr line_addr = cpkt->getBlockAddr(linesize); auto sf_it = cachedLocations.find(line_addr); bool is_hit = (sf_it != cachedLocations.end()); @@ -188,15 +182,12 @@ SnoopFilter::lookupSnoop(const Packet* cpkt) "snoop filter exceeded capacity of %d cache blocks\n", maxEntryCount); - // If the snoop filter has no entry and its an uncacheable - // request, do not create a new snoop filter entry, simply return - // a NULL portlist. - if (!is_hit && cpkt->req->isUncacheable()) + // If the snoop filter has no entry, simply return a NULL + // portlist, there is no point creating an entry only to remove it + // later + if (!is_hit) return snoopDown(lookupLatency); - // If no hit in snoop filter create a new element and update iterator - if (!is_hit) - sf_it = cachedLocations.emplace(line_addr, SnoopItem()).first; SnoopItem& sf_item = sf_it->second; DPRINTF(SnoopFilter, "%s: old SF value %x.%x\n", @@ -205,13 +196,12 @@ SnoopFilter::lookupSnoop(const Packet* cpkt) SnoopMask interested = (sf_item.holder | sf_item.requested); totSnoops++; - if (is_hit) { - // Single bit set -> value is a power of two - if (isPow2(interested)) - hitSingleSnoops++; - else - hitMultiSnoops++; - } + // Single bit set -> value is a power of two + if (isPow2(interested)) + hitSingleSnoops++; + else + hitMultiSnoops++; + // ReadEx and Writes require both invalidation and exlusivity, while reads // require neither. Writebacks on the other hand require exclusivity but // not the invalidation. Previously Writebacks did not generate upward @@ -296,23 +286,28 @@ SnoopFilter::updateSnoopForward(const Packet* cpkt, __func__, rsp_port.name(), req_port.name(), cpkt->getAddr(), cpkt->cmdString()); + assert(cpkt->isResponse()); + assert(cpkt->memInhibitAsserted()); + Addr line_addr = cpkt->getBlockAddr(linesize); auto sf_it = cachedLocations.find(line_addr); - if (sf_it == cachedLocations.end()) - sf_it = cachedLocations.emplace(line_addr, SnoopItem()).first; - SnoopItem& sf_item = sf_it->second; - SnoopMask rsp_mask M5_VAR_USED = portToMask(rsp_port); + bool is_hit = sf_it != cachedLocations.end(); - assert(cpkt->isResponse()); - assert(cpkt->memInhibitAsserted()); + // Nothing to do if it is not a hit + if (!is_hit) + return; + + SnoopItem& sf_item = sf_it->second; DPRINTF(SnoopFilter, "%s: old SF value %x.%x\n", __func__, sf_item.requested, sf_item.holder); - // Remote (to this snoop filter) snoops update the filter already when they - // arrive from below, because we may not see any response. + // Remote (to this snoop filter) snoops update the filter + // already when they arrive from below, because we may not see + // any response. if (cpkt->needsExclusive()) { - // If the request to this snoop response hit an in-flight transaction, + // If the request to this snoop response hit an in-flight + // transaction, // the holder was not reset -> no assertion & do that here, now! //assert(sf_item.holder == 0); sf_item.holder = 0; @@ -320,6 +315,7 @@ SnoopFilter::updateSnoopForward(const Packet* cpkt, DPRINTF(SnoopFilter, "%s: new SF value %x.%x\n", __func__, sf_item.requested, sf_item.holder); eraseIfNullEntry(sf_it); + } void |