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fix prefetch lockup on L2 hit

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This commit is contained in:
Henry Cook 2015-11-15 12:51:34 -08:00
parent e12efab423
commit 03fa06e6e7
1 changed files with 8 additions and 1 deletions
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9
uncore/src/main/scala/cache.scala
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@ -876,8 +876,10 @@ class L2AcquireTracker(trackerId: Int)(implicit p: Parameters) extends L2XactTra
val needs_inner_probes = tag_match && coh.inner.requiresProbes(xact) val needs_inner_probes = tag_match && coh.inner.requiresProbes(xact)
val should_update_meta = !tag_match && xact.allocate() || val should_update_meta = !tag_match && xact.allocate() ||
is_hit && pending_coh_on_hit != coh is_hit && pending_coh_on_hit != coh
// Determine any changes to the coherence metadata
when (should_update_meta) { pending_meta_write := Bool(true) } when (should_update_meta) { pending_meta_write := Bool(true) }
pending_coh := Mux(is_hit, pending_coh_on_hit, Mux(tag_match, coh, pending_coh_on_miss)) pending_coh := Mux(is_hit, pending_coh_on_hit, Mux(tag_match, coh, pending_coh_on_miss))
// If we need to probe some clients, make a bitmask identifying them
when (needs_inner_probes) { when (needs_inner_probes) {
val full_sharers = coh.inner.full() val full_sharers = coh.inner.full()
val mask_self = Mux( val mask_self = Mux(
@ -886,12 +888,17 @@ class L2AcquireTracker(trackerId: Int)(implicit p: Parameters) extends L2XactTra
coh.inner.full() & ~UIntToOH(xact.client_id)) coh.inner.full() & ~UIntToOH(xact.client_id))
val mask_incoherent = mask_self & ~io.incoherent.toBits val mask_incoherent = mask_self & ~io.incoherent.toBits
pending_iprbs := mask_incoherent pending_iprbs := mask_incoherent
} }
// If a prefetch is a hit, note that we have to ack it
when (is_hit && xact.isPrefetch()) {
pending_ignt_ack := Bool(true)
}
// If the write is marked no-allocate but is already in the cache, // If the write is marked no-allocate but is already in the cache,
// we do, in fact, need to write the data to the cache // we do, in fact, need to write the data to the cache
when (is_hit && !xact.allocate() && xact.hasData()) { when (is_hit && !xact.allocate() && xact.hasData()) {
pending_writes := addPendingBitFromBufferedAcquire(xact) pending_writes := addPendingBitFromBufferedAcquire(xact)
} }
// Next: request writeback, issue probes, query outer memory, or respond
state := Mux(needs_writeback, s_wb_req, state := Mux(needs_writeback, s_wb_req,
Mux(needs_inner_probes, s_inner_probe, Mux(needs_inner_probes, s_inner_probe,
Mux(!is_hit, s_outer_acquire, s_busy))) Mux(!is_hit, s_outer_acquire, s_busy)))