riscv/rocket-chip
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fix some LLC bugs

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This commit is contained in:
Andrew Waterman 2012-07-11 17:56:39 -07:00
parent 1ebfeeca8a
commit 62a3ea4113
1 changed files with 23 additions and 16 deletions
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39
uncore/llc.scala
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@ -103,7 +103,7 @@ class LLCMSHRFile(sets: Int, ways: Int, outstanding: Int) extends Component
val repl_dirty = Bool(INPUT)
val repl_tag = UFix(PADDR_BITS - OFFSET_BITS - log2Up(sets), INPUT)
val data = (new FIFOIO) { new LLCDataReq(ways) }
val tag = (new PipeIO) { new Bundle {
val tag = (new FIFOIO) { new Bundle {
val addr = UFix(width = PADDR_BITS - OFFSET_BITS)
val way = UFix(width = log2Up(ways))
} }
@ -156,7 +156,7 @@ class LLCMSHRFile(sets: Int, ways: Int, outstanding: Int) extends Component
val replays = Cat(Bits(0), (outstanding-1 to 0 by -1).map(i => valid(i) && mshr(i).refilled):_*)
val replay = replays.orR
val replayId = PriorityEncoder(replays)
when (replay && io.data.ready) { valid(replayId) := Bool(false) }
when (replay && io.data.ready && io.tag.ready) { valid(replayId) := Bool(false) }
val writebacks = Cat(Bits(0), (outstanding-1 to 0 by -1).map(i => valid(i) && mshr(i).old_dirty):_*)
val writeback = writebacks.orR
@ -166,7 +166,7 @@ class LLCMSHRFile(sets: Int, ways: Int, outstanding: Int) extends Component
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.data.valid := replay || writeback
io.data.valid := replay && io.tag.ready || writeback
io.data.bits.rw := Bool(false)
io.data.bits.tag := mshr(replayId).tag
io.data.bits.isWriteback := Bool(true)
@ -318,7 +318,7 @@ class DRAMSideLLC(sets: Int, ways: Int, outstanding: Int, tagLeaf: Mem[Bits], da
val memCmdArb = (new Arbiter(2)) { new MemReqCmd }
val dataArb = (new Arbiter(2)) { new LLCDataReq(ways) }
val mshr = new LLCMSHRFile(sets, ways, outstanding)
val tags = new BigMem(sets, 2, tagLeaf)(Bits(width = metaWidth*ways))
val tags = new BigMem(sets, 1, tagLeaf)(Bits(width = metaWidth*ways))
val data = new LLCData(sets, ways, dataLeaf)
val writeback = new LLCWriteback(2)
@ -333,31 +333,38 @@ class DRAMSideLLC(sets: Int, ways: Int, outstanding: Int, tagLeaf: Mem[Bits], da
val s1 = Reg() { new MemReqCmd }
when (io.cpu.req_cmd.valid && io.cpu.req_cmd.ready) { s1 := io.cpu.req_cmd.bits }
tags.io.en := (io.cpu.req_cmd.valid || replay_s1) && !stall_s1 || initialize || mshr.io.tag.valid
tags.io.addr := Mux(initialize, initCount, Mux(mshr.io.tag.valid, mshr.io.tag.bits.addr, Mux(replay_s1, s1.addr, io.cpu.req_cmd.bits.addr))(log2Up(sets)-1,0))
tags.io.rw := initialize || mshr.io.tag.valid
tags.io.wdata := Mux(initialize, UFix(0), Fill(ways, Cat(Bool(false), Bool(true), mshr.io.tag.bits.addr(mshr.io.tag.bits.addr.width-1, mshr.io.tag.bits.addr.width-tagWidth))))
tags.io.wmask := FillInterleaved(metaWidth, Mux(initialize, Fix(-1, ways), UFixToOH(mshr.io.tag.bits.way)))
val stall_s2 = Bool()
val s2_valid = Reg(resetVal = Bool(false))
s2_valid := s1_valid && !replay_s1 && !stall_s1 || stall_s2
val s2 = Reg() { new MemReqCmd }
when (s1_valid && !stall_s1 && !replay_s1) { s2 := s1 }
val s2_tags = Vec(ways) { Bits(width = metaWidth) }
for (i <- 0 until ways) s2_tags(i) := tags.io.rdata(metaWidth*(i+1)-1, metaWidth*i)
val s2_tags = Vec(ways) { Reg() { Bits(width = metaWidth) } }
when (s1_valid && !stall_s1 && !replay_s1) {
s2 := s1
for (i <- 0 until ways)
s2_tags(i) := tags.io.rdata(metaWidth*(i+1)-1, metaWidth*i)
}
val s2_hits = s2_tags.map(t => t(tagWidth) && s2.addr(s2.addr.width-1, s2.addr.width-tagWidth) === t(tagWidth-1, 0))
val s2_hit_way = OHToUFix(s2_hits)
val s2_hit = s2_hits.reduceLeft(_||_)
stall_s1 := initialize || mshr.io.tag.valid || s2_valid && !s2_hit || stall_s2
val s2_hit_dirty = s2_tags(s2_hit_way)(tagWidth+1)
val repl_way = LFSR16(s2_valid)(log2Up(ways)-1, 0)
val repl_tag = s2_tags(repl_way).toUFix
val setDirty = s2_valid && s2.rw && s2_hit && !s2_hit_dirty
stall_s1 := initialize || mshr.io.tag.valid || setDirty || s2_valid && !s2_hit || stall_s2
tags.io.en := (io.cpu.req_cmd.valid || replay_s1) && !stall_s1 || initialize || setDirty || mshr.io.tag.valid
tags.io.addr := Mux(initialize, initCount, Mux(setDirty, s2.addr, Mux(mshr.io.tag.valid, mshr.io.tag.bits.addr, Mux(replay_s1, s1.addr, io.cpu.req_cmd.bits.addr)))(log2Up(sets)-1,0))
tags.io.rw := initialize || setDirty || mshr.io.tag.valid
tags.io.wdata := Mux(initialize, UFix(0), Fill(ways, Cat(setDirty, Bool(true), Mux(setDirty, s2.addr, mshr.io.tag.bits.addr)(mshr.io.tag.bits.addr.width-1, mshr.io.tag.bits.addr.width-tagWidth))))
tags.io.wmask := FillInterleaved(metaWidth, Mux(initialize, Fix(-1, ways), UFixToOH(Mux(setDirty, s2_hit_way, mshr.io.tag.bits.way))))
mshr.io.cpu.valid := s2_valid && !s2_hit && !s2.rw
mshr.io.cpu.bits := s2
mshr.io.repl_way := repl_way
mshr.io.repl_dirty := repl_tag(tagWidth).toBool
mshr.io.repl_dirty := repl_tag(tagWidth+1, tagWidth).andR
mshr.io.repl_tag := repl_tag
mshr.io.mem.resp := io.mem.resp
mshr.io.tag.ready := !setDirty
data.io.req <> dataArb.io.out
data.io.mem_resp := io.mem.resp
@ -379,7 +386,7 @@ class DRAMSideLLC(sets: Int, ways: Int, outstanding: Int, tagLeaf: Mem[Bits], da
dataArb.io.in(0) <> mshr.io.data
dataArb.io.in(1).valid := s2_valid && s2_hit
dataArb.io.in(1).bits := s2
dataArb.io.in(1).bits.way := OHToUFix(s2_hits)
dataArb.io.in(1).bits.way := s2_hit_way
dataArb.io.in(1).bits.isWriteback := Bool(false)
stall_s2 := s2_valid && !Mux(s2_hit, dataArb.io.in(1).ready, Mux(s2.rw, writeback.io.req(1).ready, mshr.io.cpu.ready))