riscv/rocket-chip
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don't initiate llc refill until writeback drains

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This commit is contained in:
Andrew Waterman 2012-12-04 06:57:53 -08:00
parent 8103676b37
commit 50e9d952e8
1 changed files with 8 additions and 2 deletions
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10
uncore/src/llc.scala
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@ -109,6 +109,7 @@ class LLCMSHRFile(sets: Int, ways: Int, outstanding: Int) extends Component
val requested = Bool() val requested = Bool()
val old_dirty = Bool() val old_dirty = Bool()
val old_tag = UFix(width = PADDR_BITS - OFFSET_BITS - log2Up(sets)) val old_tag = UFix(width = PADDR_BITS - OFFSET_BITS - log2Up(sets))
val wb_busy = Bool()
override def clone = new MSHR().asInstanceOf[this.type] override def clone = new MSHR().asInstanceOf[this.type]
} }
@ -124,12 +125,13 @@ class LLCMSHRFile(sets: Int, ways: Int, outstanding: Int) extends Component
mshr(freeId).way := io.repl_way mshr(freeId).way := io.repl_way
mshr(freeId).old_dirty := io.repl_dirty mshr(freeId).old_dirty := io.repl_dirty
mshr(freeId).old_tag := io.repl_tag mshr(freeId).old_tag := io.repl_tag
mshr(freeId).wb_busy := Bool(false)
mshr(freeId).requested := Bool(false) mshr(freeId).requested := Bool(false)
mshr(freeId).refillCount := UFix(0) mshr(freeId).refillCount := UFix(0)
mshr(freeId).refilled := Bool(false) mshr(freeId).refilled := Bool(false)
} }
val requests = Cat(Bits(0), (outstanding-1 to 0 by -1).map(i => valid(i) && !mshr(i).old_dirty && !mshr(i).requested):_*) val requests = Cat(Bits(0), (outstanding-1 to 0 by -1).map(i => valid(i) && !mshr(i).old_dirty && !mshr(i).wb_busy && !mshr(i).requested):_*)
val request = requests.orR val request = requests.orR
val requestId = PriorityEncoder(requests) val requestId = PriorityEncoder(requests)
when (io.mem.req_cmd.valid && io.mem.req_cmd.ready) { mshr(requestId).requested := Bool(true) } when (io.mem.req_cmd.valid && io.mem.req_cmd.ready) { mshr(requestId).requested := Bool(true) }
@ -149,7 +151,11 @@ class LLCMSHRFile(sets: Int, ways: Int, outstanding: Int) extends Component
val writebacks = Cat(Bits(0), (outstanding-1 to 0 by -1).map(i => valid(i) && mshr(i).old_dirty):_*) val writebacks = Cat(Bits(0), (outstanding-1 to 0 by -1).map(i => valid(i) && mshr(i).old_dirty):_*)
val writeback = writebacks.orR val writeback = writebacks.orR
val writebackId = PriorityEncoder(writebacks) val writebackId = PriorityEncoder(writebacks)
when (writeback && io.data.ready && !replay) { mshr(writebackId).old_dirty := Bool(false) } when (writeback && io.data.ready && !replay) {
mshr(writebackId).old_dirty := Bool(false)
mshr(writebackId).wb_busy := Bool(true)
}
mshr.foreach(m => when (m.wb_busy && io.data.ready) { m.wb_busy := Bool(false) })
val conflicts = Cat(Bits(0), (0 until outstanding).map(i => valid(i) && io.cpu.bits.addr(log2Up(sets)-1, 0) === mshr(i).addr(log2Up(sets)-1, 0)):_*) val conflicts = Cat(Bits(0), (0 until outstanding).map(i => valid(i) && io.cpu.bits.addr(log2Up(sets)-1, 0) === mshr(i).addr(log2Up(sets)-1, 0)):_*)
io.cpu.ready := !conflicts.orR && !validBits.andR io.cpu.ready := !conflicts.orR && !validBits.andR