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-rw-r--r--src/mem/packet.cc14
-rw-r--r--src/mem/packet.hh10
-rwxr-xr-xsrc/mem/snoop_filter.cc36
3 files changed, 31 insertions, 29 deletions
diff --git a/src/mem/packet.cc b/src/mem/packet.cc
index 289bc81bc..cacfc1d3b 100644
--- a/src/mem/packet.cc
+++ b/src/mem/packet.cc
@@ -83,7 +83,7 @@ MemCmd::commandInfo[] =
{ SET5(IsWrite, NeedsWritable, IsRequest, NeedsResponse, HasData),
WriteResp, "WriteReq" },
/* WriteResp */
- { SET3(IsWrite, NeedsWritable, IsResponse), InvalidCmd, "WriteResp" },
+ { SET2(IsWrite, IsResponse), InvalidCmd, "WriteResp" },
/* WritebackDirty */
{ SET4(IsWrite, IsRequest, IsEviction, HasData),
InvalidCmd, "WritebackDirty" },
@@ -117,7 +117,7 @@ MemCmd::commandInfo[] =
IsRequest, NeedsResponse),
UpgradeResp, "SCUpgradeReq" },
/* UpgradeResp */
- { SET3(NeedsWritable, IsUpgrade, IsResponse),
+ { SET2(IsUpgrade, IsResponse),
InvalidCmd, "UpgradeResp" },
/* SCUpgradeFailReq: generates UpgradeFailResp but still gets the data */
{ SET6(IsRead, NeedsWritable, IsInvalidate,
@@ -125,7 +125,7 @@ MemCmd::commandInfo[] =
UpgradeFailResp, "SCUpgradeFailReq" },
/* UpgradeFailResp - Behaves like a ReadExReq, but notifies an SC
* that it has failed, acquires line as Dirty*/
- { SET4(IsRead, NeedsWritable, IsResponse, HasData),
+ { SET3(IsRead, IsResponse, HasData),
InvalidCmd, "UpgradeFailResp" },
/* ReadExReq - Read issues by a cache, always cache-line aligned,
* and the response is guaranteed to be writeable (exclusive or
@@ -134,7 +134,7 @@ MemCmd::commandInfo[] =
ReadExResp, "ReadExReq" },
/* ReadExResp - Response matching a read exclusive, as we check
* the need for exclusive also on responses */
- { SET4(IsRead, NeedsWritable, IsResponse, HasData),
+ { SET3(IsRead, IsResponse, HasData),
InvalidCmd, "ReadExResp" },
/* ReadCleanReq - Read issued by a cache, always cache-line
* aligned, and the response is guaranteed to not contain dirty data
@@ -157,13 +157,13 @@ MemCmd::commandInfo[] =
IsRequest, NeedsResponse, HasData),
StoreCondResp, "StoreCondFailReq" },
/* StoreCondResp */
- { SET4(IsWrite, NeedsWritable, IsLlsc, IsResponse),
+ { SET3(IsWrite, IsLlsc, IsResponse),
InvalidCmd, "StoreCondResp" },
/* SwapReq -- for Swap ldstub type operations */
{ SET6(IsRead, IsWrite, NeedsWritable, IsRequest, HasData, NeedsResponse),
SwapResp, "SwapReq" },
/* SwapResp -- for Swap ldstub type operations */
- { SET5(IsRead, IsWrite, NeedsWritable, IsResponse, HasData),
+ { SET4(IsRead, IsWrite, IsResponse, HasData),
InvalidCmd, "SwapResp" },
/* IntReq -- for interrupts */
{ SET4(IsWrite, IsRequest, NeedsResponse, HasData),
@@ -190,7 +190,7 @@ MemCmd::commandInfo[] =
{ SET4(IsInvalidate, IsRequest, NeedsWritable, NeedsResponse),
InvalidateResp, "InvalidateReq" },
/* Invalidation Response */
- { SET3(IsInvalidate, IsResponse, NeedsWritable),
+ { SET2(IsInvalidate, IsResponse),
InvalidCmd, "InvalidateResp" }
};
diff --git a/src/mem/packet.hh b/src/mem/packet.hh
index 94508f697..32c4cf631 100644
--- a/src/mem/packet.hh
+++ b/src/mem/packet.hh
@@ -502,7 +502,15 @@ class Packet : public Printable
bool isUpgrade() const { return cmd.isUpgrade(); }
bool isRequest() const { return cmd.isRequest(); }
bool isResponse() const { return cmd.isResponse(); }
- bool needsWritable() const { return cmd.needsWritable(); }
+ bool needsWritable() const
+ {
+ // we should never check if a response needsWritable, the
+ // request has this flag, and for a response we should rather
+ // look at the hasSharers flag (if not set, the response is to
+ // be considered writable)
+ assert(isRequest());
+ return cmd.needsWritable();
+ }
bool needsResponse() const { return cmd.needsResponse(); }
bool isInvalidate() const { return cmd.isInvalidate(); }
bool isEviction() const { return cmd.isEviction(); }
diff --git a/src/mem/snoop_filter.cc b/src/mem/snoop_filter.cc
index b1ccc12c9..9d02ed249 100755
--- a/src/mem/snoop_filter.cc
+++ b/src/mem/snoop_filter.cc
@@ -257,17 +257,14 @@ SnoopFilter::updateSnoopResponse(const Packet* cpkt,
panic_if(!(sf_item.requested & req_mask), "SF value %x.%x missing "\
"the original request\n", sf_item.requested, sf_item.holder);
- // Update the residency of the cache line.
- if (cpkt->needsWritable() || !cpkt->hasSharers()) {
- DPRINTF(SnoopFilter, "%s: dropping %x because needs: %i writable: %i "\
- "SF val: %x.%x\n", __func__, rsp_mask,
- cpkt->needsWritable(), !cpkt->hasSharers(),
+ // If the snoop response has no sharers the line is passed in
+ // Modified state, and we know that there are no other copies, or
+ // they will all be invalidated imminently
+ if (!cpkt->hasSharers()) {
+ DPRINTF(SnoopFilter,
+ "%s: dropping %x because non-shared snoop "
+ "response SF val: %x.%x\n", __func__, rsp_mask,
sf_item.requested, sf_item.holder);
-
- sf_item.holder &= ~rsp_mask;
- // The snoop filter does not see any ACKs from non-responding sharers
- // that have been invalidated :( So below assert would be nice, but..
- //assert(sf_item.holder == 0);
sf_item.holder = 0;
}
assert(!cpkt->isWriteback());
@@ -302,14 +299,10 @@ SnoopFilter::updateSnoopForward(const Packet* cpkt,
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.
- if (cpkt->needsWritable()) {
- // 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);
+ // If the snoop response has no sharers the line is passed in
+ // Modified state, and we know that there are no other copies, or
+ // they will all be invalidated imminently
+ if (!cpkt->hasSharers()) {
sf_item.holder = 0;
}
DPRINTF(SnoopFilter, "%s: new SF value %x.%x\n",
@@ -343,9 +336,10 @@ SnoopFilter::updateResponse(const Packet* cpkt, const SlavePort& slave_port)
panic_if(!(sf_item.requested & slave_mask), "SF value %x.%x missing "\
"request bit\n", sf_item.requested, sf_item.holder);
- // Update the residency of the cache line. Here we assume that the
- // line has been zapped in all caches that are not the responder.
- if (cpkt->needsWritable() || !cpkt->hasSharers())
+ // Update the residency of the cache line. If the response has no
+ // sharers we know that the line has been invalidated in all
+ // branches that are not where we are responding to.
+ if (!cpkt->hasSharers())
sf_item.holder = 0;
sf_item.holder |= slave_mask;
sf_item.requested &= ~slave_mask;
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-16 19:57:16 +0000