changeset a7cb233caa7b in /z/repo/gem5
details: http://repo.gem5.org/gem5?cmd=changeset;node=a7cb233caa7b
description:
cpu: Fix memory access in Minor not setting parent Request flags
This patch fixes cases where uncacheable/memory type flags are not set
correctly on a memory op which is split in the LSQ. Without this
patch, request->request if freely used to check flags where the flags
should actually come from the accumulation of request fragment flags.
This patch also fixes a bug where an uncacheable access which passes
through tryToSendRequest more than once can increment
LSQ::numAccessesInMemorySystem more than once.
diffstat:
src/cpu/minor/lsq.cc | 4 +++-
src/cpu/minor/lsq.hh | 6 +++++-
2 files changed, 8 insertions(+), 2 deletions(-)
diffs (37 lines):
diff -r bf52480abd01 -r a7cb233caa7b src/cpu/minor/lsq.cc
--- a/src/cpu/minor/lsq.cc Fri Sep 12 10:22:47 2014 -0400
+++ b/src/cpu/minor/lsq.cc Fri Sep 12 10:22:49 2014 -0400
@@ -476,6 +476,8 @@
makePacketForRequest(*fragment, isLoad, this, request_data);
fragmentPackets.push_back(fragment_packet);
+ /* Accumulate flags in parent request */
+ request.setFlags(fragment->getFlags());
}
/* Might as well make the overall/response packet here */
@@ -1029,7 +1031,7 @@
/* Remember if this is an access which can't be idly
* discarded by an interrupt */
- if (!bufferable) {
+ if (!bufferable && !request->issuedToMemory) {
numAccessesIssuedToMemory++;
request->issuedToMemory = true;
}
diff -r bf52480abd01 -r a7cb233caa7b src/cpu/minor/lsq.hh
--- a/src/cpu/minor/lsq.hh Fri Sep 12 10:22:47 2014 -0400
+++ b/src/cpu/minor/lsq.hh Fri Sep 12 10:22:49 2014 -0400
@@ -585,7 +585,11 @@
protected:
/** Count of the number of mem. accesses which have left the
- * requests queue and are in the 'wild' in the memory system. */
+ * requests queue and are in the 'wild' in the memory system and who
+ * *must not* be interrupted as they are not normal cacheable
+ * accesses. This is a count of the number of in-flight requests
+ * with issuedToMemory set who have visited tryToSendRequest at least
+ * once */
unsigned int numAccessesInMemorySystem;
/** Number of requests in the DTLB in the requests queue */
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