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Refactored WritebackUnit

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This commit is contained in:
Henry Cook 2015-04-21 22:23:04 -07:00
parent 4c7969b2b3
commit 11b5222d01
1 changed files with 105 additions and 140 deletions
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245
uncore/src/main/scala/cache.scala
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@ -192,9 +192,8 @@ abstract class L2HellaCacheModule extends Module with L2HellaCacheParameters {
}
def doInternalInputRouting[T <: HasL2Id](in: ValidIO[T], outs: Seq[ValidIO[T]]) {
val idx = in.bits.id
outs.map(_.bits := in.bits)
outs.zipWithIndex.map { case (o,i) => o.valid := in.valid && idx === UInt(i) }
outs.zipWithIndex.map { case (o,i) => o.valid := in.valid && in.bits.id === UInt(i) }
}
}
@ -621,7 +620,7 @@ class L2AcquireTracker(trackerId: Int) extends L2XactTracker {
max = io.inner.tlNCachingClients,
up = io.inner.probe,
down = io.inner.release)._1
val (pending_ognts, oacq_data_idx, oacq_data_done, ognt_data_idx, ognt_data_done) =
val (pending_ognt, oacq_data_idx, oacq_data_done, ognt_data_idx, ognt_data_done) =
connectTwoWayBeatCounter(
max = 1,
up = io.outer.acquire,
@ -646,7 +645,7 @@ class L2AcquireTracker(trackerId: Int) extends L2XactTracker {
pending_writes.orR ||
pending_resps.orR ||
pending_puts.orR ||
pending_ognts ||
pending_ognt ||
ignt_q.io.count > UInt(0) ||
//pending_meta_write || // Has own state: s_meta_write
pending_ifins)
@ -794,8 +793,7 @@ class L2AcquireTracker(trackerId: Int) extends L2XactTracker {
ignt_q.io.deq.ready := ignt_data_done
io.inner.grant.valid := state === s_busy &&
ignt_q.io.deq.valid &&
(!io.ignt().hasData() ||
pending_ignt_data(ignt_data_idx))
(!io.ignt().hasData() || pending_ignt_data(ignt_data_idx))
// Make the Grant message using the data stored in the secondary miss queue
io.inner.grant.bits := pending_coh.inner.makeGrant(
pri = xact,
@ -826,9 +824,7 @@ class L2AcquireTracker(trackerId: Int) extends L2XactTracker {
addPendingBitWhenBeatIsGetOrAtomic(io.inner.acquire) |
addPendingBitWhenBeatHasPartialWritemask(io.inner.acquire)
val curr_read_beat = PriorityEncoder(pending_reads)
io.data.read.valid := state === s_busy &&
pending_reads.orR &&
!pending_ognts
io.data.read.valid := state === s_busy && pending_reads.orR && !pending_ognt
io.data.read.bits.id := UInt(trackerId)
io.data.read.bits.way_en := xact_way_en
io.data.read.bits.addr_idx := xact.addr_block(idxMSB,idxLSB)
@ -847,7 +843,7 @@ class L2AcquireTracker(trackerId: Int) extends L2XactTracker {
val curr_write_beat = PriorityEncoder(pending_writes)
io.data.write.valid := state === s_busy &&
pending_writes.orR &&
!pending_ognts &&
!pending_ognt &&
!pending_reads(curr_write_beat) &&
!pending_resps(curr_write_beat)
io.data.write.bits.id := UInt(trackerId)
@ -870,10 +866,11 @@ class L2AcquireTracker(trackerId: Int) extends L2XactTracker {
io.meta.write.bits.data.coh := pending_coh
io.wb.req.valid := state === s_wb_req
io.wb.req.bits.addr_block := Cat(xact_old_meta.tag, xact.addr_block(idxMSB,idxLSB))
io.wb.req.bits.id := UInt(trackerId)
io.wb.req.bits.idx := xact.addr_block(idxMSB,idxLSB)
io.wb.req.bits.tag := xact_old_meta.tag
io.wb.req.bits.coh := xact_old_meta.coh
io.wb.req.bits.way_en := xact_way_en
io.wb.req.bits.id := UInt(trackerId)
// Handling of secondary misses (Gets and Puts only for now)
when(io.inner.acquire.fire() && io.iacq().hasData()) { // state <= s_meta_wrtie
@ -961,9 +958,7 @@ class L2AcquireTracker(trackerId: Int) extends L2XactTracker {
// These IOs are used for routing in the parent
val in_same_set = xact.addr_block(idxMSB,idxLSB) === io.iacq().addr_block(idxMSB,idxLSB)
io.has_release_match := xact.conflicts(io.irel()) &&
!io.irel().isVoluntary() &&
(state === s_inner_probe)
io.has_release_match := xact.conflicts(io.irel()) && !io.irel().isVoluntary() && io.inner.release.ready
io.has_acquire_match := can_merge_iacq_put || can_merge_iacq_get
io.has_acquire_conflict := in_same_set && (state != s_idle) && !io.has_acquire_match
//TODO: relax from in_same_set to xact.conflicts(io.iacq())?
@ -974,10 +969,8 @@ class L2AcquireTracker(trackerId: Int) extends L2XactTracker {
"AcquireTracker accepted data beat from different network source than initial request.")
}
class L2WritebackReq extends L2HellaCacheBundle
with HasL2Id {
val addr_block = UInt(width = blockAddrBits) // TODO: assumes same block size
val coh = new HierarchicalMetadata
class L2WritebackReq extends L2Metadata with HasL2Id {
val idx = Bits(width = idxBits)
val way_en = Bits(width = nWays)
}
@ -996,136 +989,108 @@ class L2WritebackUnitIO extends HierarchicalXactTrackerIO {
class L2WritebackUnit(trackerId: Int) extends L2XactTracker {
val io = new L2WritebackUnitIO
val s_idle :: s_inner_probe :: s_data_read :: s_data_resp :: s_outer_release :: s_outer_grant :: s_wb_resp :: Nil = Enum(UInt(), 7)
val s_idle :: s_inner_probe :: s_busy :: s_outer_grant :: s_wb_resp :: Nil = Enum(UInt(), 5)
val state = Reg(init=s_idle)
val xact_addr_block = Reg(io.wb.req.bits.addr_block.clone)
val xact_coh = Reg{ new HierarchicalMetadata }
val xact_way_en = Reg{ Bits(width = nWays) }
val data_buffer = Vec.fill(innerDataBeats){ Reg(io.irel().data.clone) }
val xact_id = Reg{ UInt() }
val xact = Reg(new L2WritebackReq)
val data_buffer = Vec.fill(innerDataBeats){ Reg(init=UInt(0, width = innerDataBits)) }
val xact_addr_block = Cat(xact.tag, xact.idx)
val irel_had_data = Reg(init = Bool(false))
val irel_cnt = Reg(init = UInt(0, width = log2Up(io.inner.tlNCachingClients+1)))
val pending_probes = Reg(init = Bits(0, width = io.inner.tlNCachingClients))
val curr_probe_dst = PriorityEncoder(pending_probes)
val full_sharers = io.wb.req.bits.coh.inner.full()
val mask_incoherent = full_sharers & ~io.incoherent.toBits
val pending_irels =
connectTwoWayBeatCounter(max = io.inner.tlNCachingClients, up = io.inner.probe, down = io.inner.release)._1
val (pending_ognt, orel_data_idx, orel_data_done, ognt_data_idx, ognt_data_done) =
connectTwoWayBeatCounter(max = 1, up = io.outer.release, down = io.outer.grant)
val pending_iprbs = Reg(init = Bits(0, width = io.inner.tlNCachingClients))
val pending_reads = Reg(init=Bits(0, width = io.inner.tlDataBeats))
val pending_resps = Reg(init=Bits(0, width = io.inner.tlDataBeats))
val pending_orel_data = Reg(init=Bits(0, width = io.inner.tlDataBeats))
val irel_data_done = connectIncomingDataBeatCounter(io.inner.release)
val (orel_data_cnt, orel_data_done) = connectOutgoingDataBeatCounter(io.outer.release)
val (read_data_cnt, read_data_done) = connectInternalDataBeatCounter(io.data.read)
val resp_data_done = connectInternalDataBeatCounter(io.data.resp)
// Start the writeback sub-transaction
io.wb.req.ready := state === s_idle
val pending_icoh_on_irel = xact_coh.inner.onRelease(io.irel())
val pending_ocoh_on_irel = xact_coh.outer.onHit(M_XWR) // WB is a write
val pending_ofin_on_ognt = io.ognt().makeFinish()
// Track which clients yet need to be probed and make Probe message
pending_iprbs := pending_iprbs & dropPendingBitAtDest(io.inner.probe)
val curr_probe_dst = PriorityEncoder(pending_iprbs)
io.inner.probe.valid := state === s_inner_probe && pending_iprbs.orR
io.inner.probe.bits := xact.coh.inner.makeProbeForVoluntaryWriteback(curr_probe_dst, xact_addr_block)
io.has_acquire_conflict := Bool(false)
io.has_acquire_match := Bool(false)
io.has_release_match := !io.irel().isVoluntary() &&
io.irel().conflicts(xact_addr_block) &&
(state === s_inner_probe)
// Handle incoming releases from clients, which may reduce sharer counts
// and/or write back dirty data
val inner_coh_on_irel = xact.coh.inner.onRelease(io.irel())
val outer_coh_on_irel = xact.coh.outer.onHit(M_XWR)
io.inner.release.ready := state === s_inner_probe || state === s_busy
when(io.inner.release.fire()) {
xact.coh.inner := inner_coh_on_irel
when(io.irel().hasData()) { xact.coh.outer := outer_coh_on_irel } // WB is a write
data_buffer(io.inner.release.bits.addr_beat) := io.inner.release.bits.data
}
io.outer.acquire.valid := Bool(false)
io.outer.probe.ready := Bool(false)
io.outer.release.valid := Bool(false) // default
io.outer.release.bits := xact_coh.outer.makeVoluntaryWriteback(
client_xact_id = UInt(trackerId),
addr_block = xact_addr_block,
addr_beat = orel_data_cnt,
data = data_buffer(orel_data_cnt))
io.outer.grant.ready := Bool(false) // default
io.inner.probe.valid := Bool(false)
io.inner.probe.bits := xact_coh.inner.makeProbeForVoluntaryWriteback(curr_probe_dst, xact_addr_block)
io.inner.grant.valid := Bool(false)
io.inner.acquire.ready := Bool(false)
io.inner.release.ready := Bool(false)
io.inner.finish.ready := Bool(false)
io.data.read.valid := Bool(false)
// If a release didn't write back data, have to read it from data array
pending_reads := (pending_reads &
dropPendingBit(io.data.read) &
dropPendingBitWhenBeatHasData(io.inner.release))
val curr_read_beat = PriorityEncoder(pending_reads)
io.data.read.valid := state === s_busy && pending_reads.orR
io.data.read.bits.id := UInt(trackerId)
io.data.read.bits.way_en := xact_way_en
io.data.read.bits.addr_idx := xact_addr_block(idxMSB,idxLSB)
io.data.read.bits.addr_beat := read_data_cnt
io.data.read.bits.way_en := xact.way_en
io.data.read.bits.addr_idx := xact.idx
io.data.read.bits.addr_beat := curr_read_beat
io.data.write.valid := Bool(false)
io.wb.req.ready := Bool(false)
io.wb.resp.valid := Bool(false)
io.wb.resp.bits.id := xact_id
switch (state) {
is(s_idle) {
io.wb.req.ready := Bool(true)
when(io.wb.req.valid) {
xact_addr_block := io.wb.req.bits.addr_block
xact_coh := io.wb.req.bits.coh
xact_way_en := io.wb.req.bits.way_en
xact_id := io.wb.req.bits.id
irel_had_data := Bool(false)
val needs_inner_probes = io.wb.req.bits.coh.inner.requiresProbesOnVoluntaryWriteback()
when(needs_inner_probes) {
pending_probes := mask_incoherent
irel_cnt := PopCount(mask_incoherent)
}
state := Mux(needs_inner_probes, s_inner_probe, s_data_read)
}
}
is(s_inner_probe) {
// Send probes
io.inner.probe.valid := pending_probes != UInt(0)
when(io.inner.probe.ready) {
pending_probes := pending_probes & ~UIntToOH(curr_probe_dst)
}
// Handle releases, which may have data being written back
io.inner.release.ready := Bool(true)
when(io.inner.release.valid) {
xact_coh.inner := pending_icoh_on_irel
// Handle released dirty data
when(io.irel().hasData()) {
irel_had_data := Bool(true)
xact_coh.outer := pending_ocoh_on_irel
data_buffer(io.irel().addr_beat) := io.irel().data
}
// We don't decrement irel_cnt until we've received all the data beats.
when(!io.irel().hasData() || irel_data_done) {
irel_cnt := irel_cnt - UInt(1)
}
}
when(irel_cnt === UInt(0)) {
state := Mux(irel_had_data, // If someone released a dirty block
s_outer_release, // write that block back, otherwise
Mux(xact_coh.outer.requiresVoluntaryWriteback(),
s_data_read, // write extant dirty data back, or just
s_wb_resp)) // drop a clean block after collecting acks
}
}
is(s_data_read) {
io.data.read.valid := Bool(true)
when(io.data.resp.valid) { data_buffer(io.data.resp.bits.addr_beat) := io.data.resp.bits.data }
when(read_data_done) { state := s_data_resp }
}
is(s_data_resp) {
when(io.data.resp.valid) { data_buffer(io.data.resp.bits.addr_beat) := io.data.resp.bits.data }
when(resp_data_done) { state := s_outer_release }
}
is(s_outer_release) {
io.outer.release.valid := Bool(true)
when(orel_data_done) {
state := Mux(io.orel().requiresAck(), s_outer_grant, s_wb_resp)
}
}
is(s_outer_grant) {
io.outer.grant.ready := Bool(true)
when(io.outer.grant.valid) {
state := s_wb_resp
}
}
is(s_wb_resp) {
io.wb.resp.valid := Bool(true)
state := s_idle
}
pending_resps := (pending_resps & dropPendingBitInternal(io.data.resp)) |
addPendingBitInternal(io.data.read)
when(io.data.resp.valid) {
data_buffer(io.data.resp.bits.addr_beat) := io.data.resp.bits.data
}
// Once the data is buffered we can write it back to outer memory
pending_orel_data := pending_orel_data |
addPendingBitWhenBeatHasData(io.inner.release) |
addPendingBitInternal(io.data.resp)
io.outer.release.valid := state === s_busy &&
(!io.orel().hasData() || pending_orel_data(orel_data_idx))
io.outer.release.bits := xact.coh.outer.makeVoluntaryWriteback(
client_xact_id = UInt(trackerId),
addr_block = xact_addr_block,
addr_beat = orel_data_idx,
data = data_buffer(orel_data_idx))
// Wait for an acknowledgement
io.outer.grant.ready := state === s_outer_grant
// Respond to the initiating transaction handler signalling completion of the writeback
io.wb.resp.valid := state === s_wb_resp
io.wb.resp.bits.id := xact.id
// State machine updates and transaction handler metadata intialization
when(state === s_idle && io.wb.req.valid) {
xact := io.wb.req.bits
val coh = io.wb.req.bits.coh
val needs_inner_probes = coh.inner.requiresProbesOnVoluntaryWriteback()
when(needs_inner_probes) { pending_iprbs := coh.inner.full() & ~io.incoherent.toBits }
pending_reads := SInt(-1, width = innerDataBeats)
pending_resps := UInt(0)
pending_orel_data := UInt(0)
state := Mux(needs_inner_probes, s_inner_probe, s_busy)
}
when(state === s_inner_probe && !(pending_iprbs.orR || pending_irels)) {
state := Mux(xact.coh.outer.requiresVoluntaryWriteback(), s_busy, s_wb_resp)
}
when(state === s_busy && orel_data_done) {
state := Mux(io.orel().requiresAck(), s_outer_grant, s_wb_resp)
}
when(state === s_outer_grant && ognt_data_done) { state := s_wb_resp }
when(state === s_wb_resp ) { state := s_idle }
// These IOs are used for routing in the parent
io.has_release_match := io.irel().conflicts(xact_addr_block) && !io.irel().isVoluntary() && io.inner.release.ready
io.has_acquire_match := Bool(false)
io.has_acquire_conflict := Bool(false)
// IOs pinned low
io.outer.acquire.valid := Bool(false)
io.outer.probe.ready := Bool(false) // TODO: handle these here
io.inner.grant.valid := Bool(false)
io.inner.acquire.ready := Bool(false)
io.inner.finish.ready := Bool(false)
}