mem-ruby: Fix MOESI_CMP_directory blocked line handling

Using recycle in the L2 controllers to put messages back into the buffer
may lead to starvation when there are many L1 requests for the same line.
This can easily trigger the deadlock detection mechanism in configurations
with many cores (16+). Replacing recycle by stall_and_wait for L1
requests avoids this issue. wakeUpBuffers calls were added to all
transitions from transient to stable states.

Change-Id: I28b8aeacc48919ccf38e69653cd9205a4153514b
Signed-off-by: Tiago Muck <tiago.muck@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/17568
Reviewed-by: Jason Lowe-Power <jason@lowepower.com>
Reviewed-by: Matthew Poremba <matthew.poremba@amd.com>
Maintainer: Jason Lowe-Power <jason@lowepower.com>
Tested-by: kokoro <noreply+kokoro@google.com>

1 files changed, 67 insertions, 10 deletions

diff --git a/src/mem/protocol/MOESI_CMP_directory-L2cache.sm b/src/mem/protocol/MOESI_CMP_directory-L2cache.sm
index 0c00bd93d..6252219e0 100644
--- a/src/mem/protocol/MOESI_CMP_directory-L2cache.sm
+++ b/src/mem/protocol/MOESI_CMP_directory-L2cache.sm
@@ -234,6 +234,7 @@ machine(MachineType:L2Cache, "Token protocol")
   void set_tbe(TBE b);
   void unset_tbe();
   MachineID mapAddressToMachine(Addr addr, MachineType mtype);
+  void wakeUpAllBuffers(Addr a);
 
   Entry getCacheEntry(Addr address), return_by_pointer="yes" {
     return static_cast(Entry, "pointer", L2cache[address]);
@@ -1537,13 +1538,6 @@ machine(MachineType:L2Cache, "Token protocol")
     localDirectory.deallocate(address);
   }
 
-  action(zz_recycleL1RequestQueue, "zz", desc="Send the head of the mandatory queue to the back of the queue.") {
-    peek(L1requestNetwork_in, RequestMsg) {
-      APPEND_TRANSITION_COMMENT(in_msg.Requestor);
-    }
-    L1requestNetwork_in.recycle(clockEdge(), cyclesToTicks(recycle_latency));
-  }
-
   action(zz_recycleRequestQueue, "\zz", desc="Send the head of the mandatory queue to the back of the queue.") {
     peek(requestNetwork_in, RequestMsg) {
       APPEND_TRANSITION_COMMENT(in_msg.Requestor);
@@ -1558,6 +1552,14 @@ machine(MachineType:L2Cache, "Token protocol")
     responseNetwork_in.recycle(clockEdge(), cyclesToTicks(recycle_latency));
   }
 
+  action(st_stallAndWaitL1RequestQueue, "st", desc="Stall and wait on the address") {
+    stall_and_wait(L1requestNetwork_in, address);
+  }
+
+  action(wa_wakeUpDependents, "wa", desc="Wake up any requests waiting for this address") {
+    wakeUpAllBuffers(address);
+  }
+
   action(da_sendDmaAckUnblock, "da", desc="Send dma ack to global directory") {
     enqueue(responseNetwork_out, ResponseMsg, response_latency) {
       out_msg.addr := address;
@@ -1576,11 +1578,11 @@ machine(MachineType:L2Cache, "Token protocol")
   //*****************************************************
 
   transition({II, IFGX, IFGS, ISFGS, IFGXX, IFLXO, OFGX, ILOW, ILOXW, ILOSW, ILOSXW, SLSW, OLSW, ILSW, IW, OW, SW, OXW, OLSXW, ILXW, IFLS, IFLO, IFLOX, IFLOXX, IFLOSX, OLSXS, IGS, IGM, IGMLS, IGMO, IGMIO, OGMIO, IGMIOF, OGMIOF, MM, SS, OO, OI, MI, MII, OLSI, ILSI, SLSS, OLSS, OLSF, IGMIOFS, ILOSD, ILOSXD, ILOD, ILXD, ILOXD}, {L1_PUTO, L1_PUTS, L1_PUTS_only, L1_PUTX}) {
-    zz_recycleL1RequestQueue;
+    st_stallAndWaitL1RequestQueue;
   }
 
   transition({II, IFGX, IFGS, ISFGS, IFGXX, IFLXO, OFGX, ILOW, ILOXW, ILOSW, ILOSXW, SLSW, OLSW, ILSW, IW, OW, SW, OXW, OLSXW, ILXW, IFLS, IFLO, IFLOX, IFLOXX, IFLOSX, OLSXS, IGS, IGM, IGMLS, IGMO, IGMIO, OGMIO, IGMIOF, OGMIOF, MM, SS, OO, OI, MI, MII, OLSI, ILSI, SLSS, OLSS, OLSF, IGMIOFS, ILOSD, ILOSXD, ILOD, ILXD, ILOXD}, {L1_GETX, L1_GETS}) {
-    zz_recycleL1RequestQueue;
+    st_stallAndWaitL1RequestQueue;
   }
 
   transition({IFGX, IFGS, ISFGS, IFGXX, IFLXO, OFGX, ILOW, ILOXW, ILOSW, ILOSXW, SLSW, OLSW, ILSW, IW, ILXW, OW, SW, OXW, OLSXW, IFLS, IFLO, IFLOX, IFLOXX, IFLOSX,OLSXS,  IGS, IGM, IGMLS, IGMO, MM, SS, OO, OI, MI, MII, OLSI, ILSI, SLSS, OLSS, OLSF, IGMIOFS, ILOSD, ILOSXD, ILOD, ILXD, ILOXD}, L2_Replacement) {
@@ -1674,6 +1676,7 @@ machine(MachineType:L2Cache, "Token protocol")
     s_deallocateTBE;
     da_sendDmaAckUnblock;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILOSX, Fwd_DMA, ILOSXD) {
@@ -1687,6 +1690,7 @@ machine(MachineType:L2Cache, "Token protocol")
     s_deallocateTBE;
     da_sendDmaAckUnblock;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILO, Fwd_DMA, ILOD) {
@@ -1700,6 +1704,7 @@ machine(MachineType:L2Cache, "Token protocol")
     s_deallocateTBE;
     da_sendDmaAckUnblock;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILX, Fwd_DMA, ILXD) {
@@ -1713,6 +1718,7 @@ machine(MachineType:L2Cache, "Token protocol")
     s_deallocateTBE;
     da_sendDmaAckUnblock;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILOX, Fwd_DMA, ILOXD) {
@@ -1726,6 +1732,7 @@ machine(MachineType:L2Cache, "Token protocol")
     s_deallocateTBE;
     da_sendDmaAckUnblock;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition({ILOS, ILOSX, ILO, ILX, ILOX, ILXW}, Data) {
@@ -1740,6 +1747,7 @@ machine(MachineType:L2Cache, "Token protocol")
     c_sendDataFromTBEToFwdGETS;
     s_deallocateTBE;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ISFGS, Data, ILOS) {
@@ -1747,6 +1755,7 @@ machine(MachineType:L2Cache, "Token protocol")
     c_sendDataFromTBEToFwdGETS;
     s_deallocateTBE;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(IFGS, Data_Exclusive, I) {
@@ -1755,6 +1764,7 @@ machine(MachineType:L2Cache, "Token protocol")
     gg_clearLocalSharers;
     s_deallocateTBE;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
 
@@ -1771,6 +1781,7 @@ machine(MachineType:L2Cache, "Token protocol")
     gg_clearLocalSharers;
     s_deallocateTBE;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition({ILOSX, ILOS}, Fwd_GETX, IFGXX) {
@@ -1801,6 +1812,7 @@ machine(MachineType:L2Cache, "Token protocol")
     gg_clearLocalSharers;
     s_deallocateTBE;
     n_popTriggerQueue;
+    wa_wakeUpDependents;
   }
 
 
@@ -1879,6 +1891,7 @@ machine(MachineType:L2Cache, "Token protocol")
     s_deallocateTBE;
     rr_deallocateL2CacheBlock;
     n_popTriggerQueue;
+    wa_wakeUpDependents;
   }
 
 
@@ -1927,6 +1940,7 @@ machine(MachineType:L2Cache, "Token protocol")
     e_sendAck;
     s_deallocateTBE;
     n_popTriggerQueue;
+    wa_wakeUpDependents;
   }
 
   transition(S, Inv, I) {
@@ -1960,6 +1974,7 @@ machine(MachineType:L2Cache, "Token protocol")
     g_recordLocalExclusive;
     s_deallocateTBE;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(OLSX, L1_GETS, OLSXS) {
@@ -1972,6 +1987,7 @@ machine(MachineType:L2Cache, "Token protocol")
   transition(OLSXS, Unblock, OLSX) {
     g_recordLocalSharer;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   // after this, can't get Fwd_GETX
@@ -2023,31 +2039,37 @@ machine(MachineType:L2Cache, "Token protocol")
   transition(IFLOX, Unblock, ILOSX) {
     g_recordLocalSharer;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(IFLS, Unblock, ILS) {
     g_recordLocalSharer;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(IFLOXX, Unblock, ILOSX) {
     g_recordLocalSharer;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(IFLOSX, Unblock, ILOSX) {
     g_recordLocalSharer;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition({IFLOSX, IFLOXX}, Exclusive_Unblock, ILX) {
     g_recordLocalExclusive;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(IFLO, Unblock, ILOS) {
     g_recordLocalSharer;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
 
@@ -2066,6 +2088,7 @@ machine(MachineType:L2Cache, "Token protocol")
     g_recordLocalExclusive;
     s_deallocateTBE;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   // LOCAL REQUESTS THAT MUST ISSUE
@@ -2316,6 +2339,7 @@ machine(MachineType:L2Cache, "Token protocol")
     f_sendUnblock;
     s_deallocateTBE;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(IGS, Exclusive_Unblock, ILX) {
@@ -2323,6 +2347,7 @@ machine(MachineType:L2Cache, "Token protocol")
     f_sendExclusiveUnblock;
     s_deallocateTBE;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(IGMO, All_Acks) {
@@ -2335,6 +2360,7 @@ machine(MachineType:L2Cache, "Token protocol")
     f_sendExclusiveUnblock;
     s_deallocateTBE;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
 
@@ -2362,6 +2388,7 @@ machine(MachineType:L2Cache, "Token protocol")
   transition(SLSS, Unblock, SLS) {
     g_recordLocalSharer;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
 
@@ -2385,6 +2412,7 @@ machine(MachineType:L2Cache, "Token protocol")
   transition(OLSS, Unblock, OLS) {
     g_recordLocalSharer;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(IGMO, Fwd_GETX, IGM) {
@@ -2418,6 +2446,7 @@ machine(MachineType:L2Cache, "Token protocol")
   transition(MM, Exclusive_Unblock, ILX) {
     g_recordLocalExclusive;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(M, L1_GETS, OO) {
@@ -2441,6 +2470,7 @@ machine(MachineType:L2Cache, "Token protocol")
   transition(SS, Unblock, SLS) {
     g_recordLocalSharer;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(O, L1_GETS, OO) {
@@ -2453,6 +2483,7 @@ machine(MachineType:L2Cache, "Token protocol")
   transition(OO, Unblock, OLS) {
     g_recordLocalSharer;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(OO, Exclusive_Unblock, ILX) {
@@ -2460,6 +2491,7 @@ machine(MachineType:L2Cache, "Token protocol")
     y_copyCacheStateToDir;
     rr_deallocateL2CacheBlock;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
 
@@ -2495,11 +2527,13 @@ machine(MachineType:L2Cache, "Token protocol")
   transition(ILSW, Unblock, ILS) {
     gg_clearSharerFromL1Response;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILOW, Unblock, ILO) {
     gg_clearSharerFromL1Response;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILOSX, L1_PUTS_only, ILOXW) {
@@ -2510,6 +2544,7 @@ machine(MachineType:L2Cache, "Token protocol")
   transition(ILOXW, Unblock, ILOX) {
     gg_clearSharerFromL1Response;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   // hmmm...keep data or drop.  Just drop for now
@@ -2526,11 +2561,13 @@ machine(MachineType:L2Cache, "Token protocol")
   transition(ILOSW, Unblock, ILOS) {
     gg_clearSharerFromL1Response;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILOSXW, Unblock, ILOSX) {
     gg_clearSharerFromL1Response;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(SLS, L1_PUTS, SLSW) {
@@ -2546,6 +2583,7 @@ machine(MachineType:L2Cache, "Token protocol")
   transition(SW, {Unblock}, S) {
     gg_clearSharerFromL1Response;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(OLS, L1_PUTS, OLSW) {
@@ -2581,16 +2619,19 @@ machine(MachineType:L2Cache, "Token protocol")
   transition(OLSXW, {Unblock}, OLSX) {
     gg_clearSharerFromL1Response;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(OW, {Unblock}, O) {
     gg_clearSharerFromL1Response;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(OXW, {Unblock}, M) {
     gg_clearSharerFromL1Response;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILX, L1_PUTX, ILXW ) {
@@ -2604,6 +2645,7 @@ machine(MachineType:L2Cache, "Token protocol")
     y_copyDirToCacheAndRemove;
     u_writeDataToCache;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   // clean writeback
@@ -2613,11 +2655,13 @@ machine(MachineType:L2Cache, "Token protocol")
     y_copyDirToCacheAndRemove;
     u_writeDataToCache;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILXW, Unblock, ILX) {
     // writeback canceled because L1 invalidated
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILSW, L1_WBCLEANDATA, SLS) {
@@ -2626,6 +2670,7 @@ machine(MachineType:L2Cache, "Token protocol")
     u_writeDataToCache;
     gg_clearSharerFromL1Response;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(IW, L1_WBCLEANDATA, S) {
@@ -2634,7 +2679,7 @@ machine(MachineType:L2Cache, "Token protocol")
     u_writeDataToCache;
     gg_clearSharerFromL1Response;
     n_popResponseQueue;
-
+    wa_wakeUpDependents;
   }
 
   // Owner can have dirty data
@@ -2644,6 +2689,7 @@ machine(MachineType:L2Cache, "Token protocol")
     gg_clearOwnerFromL1Response;
     u_writeDataToCache;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILOXW, L1_WBDIRTYDATA, M) {
@@ -2652,6 +2698,7 @@ machine(MachineType:L2Cache, "Token protocol")
     gg_clearOwnerFromL1Response;
     u_writeDataToCache;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILOXW, L1_WBCLEANDATA, M) {
@@ -2660,6 +2707,7 @@ machine(MachineType:L2Cache, "Token protocol")
     gg_clearOwnerFromL1Response;
     u_writeDataToCache;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILOSW, {L1_WBCLEANDATA, L1_WBDIRTYDATA}, OLS) {
@@ -2668,6 +2716,7 @@ machine(MachineType:L2Cache, "Token protocol")
     gg_clearOwnerFromL1Response;
     u_writeDataToCache;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILOSXW, {L1_WBCLEANDATA, L1_WBDIRTYDATA}, OLSX) {
@@ -2676,17 +2725,20 @@ machine(MachineType:L2Cache, "Token protocol")
     gg_clearOwnerFromL1Response;
     u_writeDataToCache;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
 
   transition(SLSW, {Unblock}, SLS) {
     gg_clearSharerFromL1Response;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
   transition(OLSW, {Unblock}, OLS) {
     gg_clearSharerFromL1Response;
     n_popResponseQueue;
+    wa_wakeUpDependents;
   }
 
 
@@ -2787,11 +2839,13 @@ machine(MachineType:L2Cache, "Token protocol")
     qq_sendDataFromTBEToMemory;
     s_deallocateTBE;
     m_popRequestQueue;
+    wa_wakeUpDependents;
   }
 
   transition(MII, Writeback_Nack, I) {
     s_deallocateTBE;
     m_popRequestQueue;
+    wa_wakeUpDependents;
   }
 
   transition(OI, Writeback_Nack) {
@@ -2803,17 +2857,20 @@ machine(MachineType:L2Cache, "Token protocol")
     qq_sendDataFromTBEToMemory;
     s_deallocateTBE;
     m_popRequestQueue;
+    wa_wakeUpDependents;
   }
 
   transition(MII, Writeback_Ack, I) {
     f_sendUnblock;
     s_deallocateTBE;
     m_popRequestQueue;
+    wa_wakeUpDependents;
   }
 
   transition(ILSI, Writeback_Ack, ILS) {
     f_sendUnblock;
     s_deallocateTBE;
     m_popRequestQueue;
+    wa_wakeUpDependents;
   }
 }