From f02a9338c1efaf7680f598a57ff6607e9b11120e Mon Sep 17 00:00:00 2001 From: Ali Jafri Date: Fri, 6 Nov 2015 03:26:40 -0500 Subject: mem: Avoid unnecessary snoops on writebacks and clean evictions This patch optimises the handling of writebacks and clean evictions when using a snoop filter. Instead of snooping into the caches to determine if the block is cached or not, simply set the status based on the snoop-filter result. --- src/mem/coherent_xbar.cc | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) (limited to 'src/mem/coherent_xbar.cc') diff --git a/src/mem/coherent_xbar.cc b/src/mem/coherent_xbar.cc index 223ab6ab5..8407f5350 100644 --- a/src/mem/coherent_xbar.cc +++ b/src/mem/coherent_xbar.cc @@ -198,7 +198,18 @@ CoherentXBar::recvTimingReq(PacketPtr pkt, PortID slave_port_id) " SF size: %i lat: %i\n", src_port->name(), pkt->cmdString(), pkt->getAddr(), sf_res.first.size(), sf_res.second); - forwardTiming(pkt, slave_port_id, sf_res.first); + + if (pkt->evictingBlock()) { + // for block-evicting packets, i.e. writebacks and + // clean evictions, there is no need to snoop up, as + // all we do is determine if the block is cached or + // not, instead just set it here based on the snoop + // filter result + if (!sf_res.first.empty()) + pkt->setBlockCached(); + } else { + forwardTiming(pkt, slave_port_id, sf_res.first); + } } else { forwardTiming(pkt, slave_port_id); } -- cgit v1.2.3