From abcbc4e51e21c95fa241d19ed13978ea25b26982 Mon Sep 17 00:00:00 2001 From: Andreas Hansson Date: Thu, 17 Mar 2016 09:51:22 -0400 Subject: mem: Adjust cache queue reserve to more conservative values The cache queue reserve is there as an overflow to give us enough headroom based on when we block the cache, and how many transactions we may already have accepted before actually blocking. The previous values were probably chosen to be "big enough", when we actually know that we check the MSHRs after every single allocation, and for the write buffers we know that we implicitly may need one entry for every outstanding MSHR. * * * mem: Adjust cache queue reserve to more conservative values The cache queue reserve is there as an overflow to give us enough headroom based on when we block the cache, and how many transactions we may already have accepted before actually blocking. The previous values were probably chosen to be "big enough", when we actually know that we check the MSHRs after every single allocation, and for the write buffers we know that we implicitly may need one entry for every outstanding MSHR. --- src/mem/cache/queue.hh | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'src/mem/cache/queue.hh') diff --git a/src/mem/cache/queue.hh b/src/mem/cache/queue.hh index 11d456e11..fb3e73608 100644 --- a/src/mem/cache/queue.hh +++ b/src/mem/cache/queue.hh @@ -69,7 +69,7 @@ class Queue : public Drainable /** * The total number of entries in this queue. This number is set - * as the number of entries requested plus (numReserve - 1). This + * as the number of entries requested plus any reserve. This * allows for the same number of effective entries while still * maintaining an overflow reserve. */ @@ -120,10 +120,10 @@ class Queue : public Drainable * Create a queue with a given number of entries. * * @param num_entries The number of entries in this queue. - * @param num_overflow The extra overflow entries needed. + * @param reserve The extra overflow entries needed. */ Queue(const std::string &_label, int num_entries, int reserve) : - label(_label), numEntries(num_entries + reserve - 1), + label(_label), numEntries(num_entries + reserve), numReserve(reserve), entries(numEntries), _numInService(0), allocated(0) { @@ -139,7 +139,7 @@ class Queue : public Drainable bool isFull() const { - return (allocated > numEntries - numReserve); + return (allocated >= numEntries - numReserve); } int numInService() const -- cgit v1.2.3