snoop_filter.hh (11133:81e46b63daff) | snoop_filter.hh (11135:9d09dab39689) |
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1/* 2 * Copyright (c) 2013-2015 ARM Limited 3 * All rights reserved 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software --- 20 unchanged lines hidden (view full) --- 29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * | 1/* 2 * Copyright (c) 2013-2015 ARM Limited 3 * All rights reserved 4 * 5 * The license below extends only to copyright in the software and shall 6 * not be construed as granting a license to any other intellectual 7 * property including but not limited to intellectual property relating 8 * to a hardware implementation of the functionality of the software --- 20 unchanged lines hidden (view full) --- 29 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 30 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 31 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 32 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 33 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 34 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 35 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 36 * |
37 * Authors: Stephan Diestelhorst <stephan.diestelhorst@arm.com> | 37 * Authors: Stephan Diestelhorst |
38 */ 39 40/** 41 * @file 42 * Definition of a snoop filter. 43 */ 44 45#ifndef __MEM_SNOOP_FILTER_HH__ --- 45 unchanged lines hidden (view full) --- 91 SnoopFilter (const SnoopFilterParams *p) : 92 SimObject(p), reqLookupResult(cachedLocations.end()), retryItem{0, 0}, 93 linesize(p->system->cacheLineSize()), lookupLatency(p->lookup_latency), 94 maxEntryCount(p->max_capacity / p->system->cacheLineSize()) 95 { 96 } 97 98 /** | 38 */ 39 40/** 41 * @file 42 * Definition of a snoop filter. 43 */ 44 45#ifndef __MEM_SNOOP_FILTER_HH__ --- 45 unchanged lines hidden (view full) --- 91 SnoopFilter (const SnoopFilterParams *p) : 92 SimObject(p), reqLookupResult(cachedLocations.end()), retryItem{0, 0}, 93 linesize(p->system->cacheLineSize()), lookupLatency(p->lookup_latency), 94 maxEntryCount(p->max_capacity / p->system->cacheLineSize()) 95 { 96 } 97 98 /** |
99 * Init a new snoop filter and tell it about all the 100 * slave ports of the enclosing bus. | 99 * Init a new snoop filter and tell it about all the slave ports 100 * of the enclosing bus. |
101 * 102 * @param slave_ports Slave ports that the bus is attached to. 103 */ 104 void setSlavePorts(const SnoopList& slave_ports) { 105 localSlavePortIds.resize(slave_ports.size(), InvalidPortID); 106 107 PortID id = 0; 108 for (const auto& p : slave_ports) { --- 13 unchanged lines hidden (view full) --- 122 /** 123 * Lookup a request (from a slave port) in the snoop filter and 124 * return a list of other slave ports that need forwarding of the 125 * resulting snoops. Additionally, update the tracking structures 126 * with new request information. Note that the caller must also 127 * call finishRequest once it is known if the request needs to 128 * retry or not. 129 * | 101 * 102 * @param slave_ports Slave ports that the bus is attached to. 103 */ 104 void setSlavePorts(const SnoopList& slave_ports) { 105 localSlavePortIds.resize(slave_ports.size(), InvalidPortID); 106 107 PortID id = 0; 108 for (const auto& p : slave_ports) { --- 13 unchanged lines hidden (view full) --- 122 /** 123 * Lookup a request (from a slave port) in the snoop filter and 124 * return a list of other slave ports that need forwarding of the 125 * resulting snoops. Additionally, update the tracking structures 126 * with new request information. Note that the caller must also 127 * call finishRequest once it is known if the request needs to 128 * retry or not. 129 * |
130 * @param cpkt Pointer to the request packet. Not changed. | 130 * @param cpkt Pointer to the request packet. Not changed. |
131 * @param slave_port Slave port where the request came from. 132 * @return Pair of a vector of snoop target ports and lookup latency. 133 */ 134 std::pair<SnoopList, Cycles> lookupRequest(const Packet* cpkt, 135 const SlavePort& slave_port); 136 137 /** 138 * For an un-successful request, revert the change to the snoop 139 * filter. Also take care of erasing any null entries. This method 140 * relies on the result from lookupRequest being stored in 141 * reqLookupResult. 142 * 143 * @param will_retry This request will retry on this bus / snoop filter | 131 * @param slave_port Slave port where the request came from. 132 * @return Pair of a vector of snoop target ports and lookup latency. 133 */ 134 std::pair<SnoopList, Cycles> lookupRequest(const Packet* cpkt, 135 const SlavePort& slave_port); 136 137 /** 138 * For an un-successful request, revert the change to the snoop 139 * filter. Also take care of erasing any null entries. This method 140 * relies on the result from lookupRequest being stored in 141 * reqLookupResult. 142 * 143 * @param will_retry This request will retry on this bus / snoop filter |
144 * @param cpkt Request packet, merely for sanity checking | 144 * @param cpkt Request packet, merely for sanity checking |
145 */ 146 void finishRequest(bool will_retry, const Packet* cpkt); 147 148 /** | 145 */ 146 void finishRequest(bool will_retry, const Packet* cpkt); 147 148 /** |
149 * Handle an incoming snoop from below (the master port). These can upgrade the 150 * tracking logic and may also benefit from additional steering thanks to the 151 * snoop filter. | 149 * Handle an incoming snoop from below (the master port). These 150 * can upgrade the tracking logic and may also benefit from 151 * additional steering thanks to the snoop filter. 152 * |
152 * @param cpkt Pointer to const Packet containing the snoop. 153 * @return Pair with a vector of SlavePorts that need snooping and a lookup 154 * latency. 155 */ 156 std::pair<SnoopList, Cycles> lookupSnoop(const Packet* cpkt); 157 158 /** | 153 * @param cpkt Pointer to const Packet containing the snoop. 154 * @return Pair with a vector of SlavePorts that need snooping and a lookup 155 * latency. 156 */ 157 std::pair<SnoopList, Cycles> lookupSnoop(const Packet* cpkt); 158 159 /** |
159 * Let the snoop filter see any snoop responses that turn into request responses 160 * and indicate cache to cache transfers. These will update the corresponding 161 * state in the filter. | 160 * Let the snoop filter see any snoop responses that turn into 161 * request responses and indicate cache to cache transfers. These 162 * will update the corresponding state in the filter. |
162 * 163 * @param cpkt Pointer to const Packet holding the snoop response. 164 * @param rsp_port SlavePort that sends the response. 165 * @param req_port SlavePort that made the original request and is the 166 * destination of the snoop response. 167 */ 168 void updateSnoopResponse(const Packet *cpkt, const SlavePort& rsp_port, 169 const SlavePort& req_port); 170 171 /** | 163 * 164 * @param cpkt Pointer to const Packet holding the snoop response. 165 * @param rsp_port SlavePort that sends the response. 166 * @param req_port SlavePort that made the original request and is the 167 * destination of the snoop response. 168 */ 169 void updateSnoopResponse(const Packet *cpkt, const SlavePort& rsp_port, 170 const SlavePort& req_port); 171 172 /** |
172 * Pass snoop responses that travel downward through the snoop filter and let 173 * them update the snoop filter state. No additional routing happens. | 173 * Pass snoop responses that travel downward through the snoop 174 * filter and let them update the snoop filter state. No 175 * additional routing happens. |
174 * 175 * @param cpkt Pointer to const Packet holding the snoop response. 176 * @param rsp_port SlavePort that sends the response. | 176 * 177 * @param cpkt Pointer to const Packet holding the snoop response. 178 * @param rsp_port SlavePort that sends the response. |
177 * @param req_port MasterPort through which the response leaves this cluster. | 179 * @param req_port MasterPort through which the response is forwarded. |
178 */ 179 void updateSnoopForward(const Packet *cpkt, const SlavePort& rsp_port, 180 const MasterPort& req_port); 181 182 /** | 180 */ 181 void updateSnoopForward(const Packet *cpkt, const SlavePort& rsp_port, 182 const MasterPort& req_port); 183 184 /** |
183 * Update the snoop filter with a response from below (outer / other cache, 184 * or memory) and update the tracking information in the snoop filter. | 185 * Update the snoop filter with a response from below (outer / 186 * other cache, or memory) and update the tracking information in 187 * the snoop filter. |
185 * 186 * @param cpkt Pointer to const Packet holding the snoop response. | 188 * 189 * @param cpkt Pointer to const Packet holding the snoop response. |
187 * @param slave_port SlavePort that made the original request and is the target 188 * of this response. | 190 * @param slave_port SlavePort that made the original request and 191 * is the target of this response. |
189 */ 190 void updateResponse(const Packet *cpkt, const SlavePort& slave_port); 191 | 192 */ 193 void updateResponse(const Packet *cpkt, const SlavePort& slave_port); 194 |
195 virtual void regStats(); 196 197 protected: 198 |
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192 /** | 199 /** |
193 * Simple factory methods for standard return values for lookupRequest | 200 * The underlying type for the bitmask we use for tracking. This 201 * limits the number of snooping ports supported per crossbar. For 202 * the moment it is an uint64_t to offer maximum 203 * scalability. However, it is possible to use e.g. a uint16_t or 204 * uint32_to slim down the footprint of the hash map (and 205 * ultimately improve the simulation performance). |
194 */ | 206 */ |
207 typedef uint64_t SnoopMask; 208 209 /** 210 * Per cache line item tracking a bitmask of SlavePorts who have an 211 * outstanding request to this line (requested) or already share a 212 * cache line with this address (holder). 213 */ 214 struct SnoopItem { 215 SnoopMask requested; 216 SnoopMask holder; 217 }; 218 /** 219 * HashMap of SnoopItems indexed by line address 220 */ 221 typedef m5::hash_map<Addr, SnoopItem> SnoopFilterCache; 222 223 /** 224 * Simple factory methods for standard return values. 225 */ |
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195 std::pair<SnoopList, Cycles> snoopAll(Cycles latency) const 196 { 197 return std::make_pair(slavePorts, latency); 198 } 199 std::pair<SnoopList, Cycles> snoopSelected(const SnoopList& slave_ports, 200 Cycles latency) const 201 { 202 return std::make_pair(slave_ports, latency); 203 } 204 std::pair<SnoopList, Cycles> snoopDown(Cycles latency) const 205 { 206 SnoopList empty; 207 return std::make_pair(empty , latency); 208 } 209 | 226 std::pair<SnoopList, Cycles> snoopAll(Cycles latency) const 227 { 228 return std::make_pair(slavePorts, latency); 229 } 230 std::pair<SnoopList, Cycles> snoopSelected(const SnoopList& slave_ports, 231 Cycles latency) const 232 { 233 return std::make_pair(slave_ports, latency); 234 } 235 std::pair<SnoopList, Cycles> snoopDown(Cycles latency) const 236 { 237 SnoopList empty; 238 return std::make_pair(empty , latency); 239 } 240 |
210 virtual void regStats(); 211 212 protected: 213 typedef uint64_t SnoopMask; 214 /** 215 * Per cache line item tracking a bitmask of SlavePorts who have an 216 * outstanding request to this line (requested) or already share a cache line 217 * with this address (holder). 218 */ 219 struct SnoopItem { 220 SnoopMask requested; 221 SnoopMask holder; 222 }; | |
223 /** | 241 /** |
224 * HashMap of SnoopItems indexed by line address 225 */ 226 typedef m5::hash_map<Addr, SnoopItem> SnoopFilterCache; 227 228 /** | |
229 * Convert a single port to a corresponding, one-hot bitmask 230 * @param port SlavePort that should be converted. 231 * @return One-hot bitmask corresponding to the port. 232 */ 233 SnoopMask portToMask(const SlavePort& port) const; 234 /** 235 * Converts a bitmask of ports into the corresponing list of ports 236 * @param ports SnoopMask of the requested ports 237 * @return SnoopList containing all the requested SlavePorts 238 */ 239 SnoopList maskToPortList(SnoopMask ports) const; 240 241 private: 242 243 /** 244 * Removes snoop filter items which have no requesters and no holders. 245 */ 246 void eraseIfNullEntry(SnoopFilterCache::iterator& sf_it); | 242 * Convert a single port to a corresponding, one-hot bitmask 243 * @param port SlavePort that should be converted. 244 * @return One-hot bitmask corresponding to the port. 245 */ 246 SnoopMask portToMask(const SlavePort& port) const; 247 /** 248 * Converts a bitmask of ports into the corresponing list of ports 249 * @param ports SnoopMask of the requested ports 250 * @return SnoopList containing all the requested SlavePorts 251 */ 252 SnoopList maskToPortList(SnoopMask ports) const; 253 254 private: 255 256 /** 257 * Removes snoop filter items which have no requesters and no holders. 258 */ 259 void eraseIfNullEntry(SnoopFilterCache::iterator& sf_it); |
260 |
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247 /** Simple hash set of cached addresses. */ 248 SnoopFilterCache cachedLocations; 249 /** 250 * Iterator used to store the result from lookupRequest until we 251 * call finishRequest. 252 */ 253 SnoopFilterCache::iterator reqLookupResult; 254 /** --- 36 unchanged lines hidden (view full) --- 291SnoopFilter::maskToPortList(SnoopMask port_mask) const 292{ 293 SnoopList res; 294 for (const auto& p : slavePorts) 295 if (port_mask & portToMask(*p)) 296 res.push_back(p); 297 return res; 298} | 261 /** Simple hash set of cached addresses. */ 262 SnoopFilterCache cachedLocations; 263 /** 264 * Iterator used to store the result from lookupRequest until we 265 * call finishRequest. 266 */ 267 SnoopFilterCache::iterator reqLookupResult; 268 /** --- 36 unchanged lines hidden (view full) --- 305SnoopFilter::maskToPortList(SnoopMask port_mask) const 306{ 307 SnoopList res; 308 for (const auto& p : slavePorts) 309 if (port_mask & portToMask(*p)) 310 res.push_back(p); 311 return res; 312} |
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299#endif // __MEM_SNOOP_FILTER_HH__ | 314#endif // __MEM_SNOOP_FILTER_HH__ |