mem-ruby: modify the TBE data state for ReadOnce_HitUpstream
When ReadOnce request hits upstream, set dataToBeInvalid to true
for R* states so that the line from the upstream is successfully dropped
at the end by Finalize_UpdateCacheFromTBE.
For UD_RU and UC_RU state, set dataValid to true to prevent it changing
to RU state when it doesn't get the snoop data response.
Change-Id: Ie83c511e8d158e18abc5c9c16bc6040ce73587bf
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/58411
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Reviewed-by: Tiago Muck <tiago.muck@arm.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
diff --git a/src/mem/ruby/protocol/chi/CHI-cache-actions.sm b/src/mem/ruby/protocol/chi/CHI-cache-actions.sm
index 8b248a5..2c47ac9 100644
--- a/src/mem/ruby/protocol/chi/CHI-cache-actions.sm
+++ b/src/mem/ruby/protocol/chi/CHI-cache-actions.sm
@@ -554,6 +554,15 @@
}
tbe.updateDirOnCompAck := false;
// no need to update or access tags/data on ReadOnce served from upstream
+
+ if (is_invalid(cache_entry)) {
+ // if we receive data, invalidate at the end so it can be dropped
+ tbe.dataToBeInvalid := true;
+ } else if (tbe.dataValid == false) {
+ // possible on UD_RU,UC_RU where cache_entry valid but tbe.dataValid == false
+ // this prevents going to RU if no data is received from snoop
+ tbe.dataValid := true;
+ }
}
