From ed969daf1aa709a62d06e7680944dc4408bb8e9d Mon Sep 17 00:00:00 2001 From: Radhika Jagtap Date: Thu, 21 Sep 2017 17:24:09 +0100 Subject: [PATCH] cpu, probe: Fix elastic trace register dependency Change-Id: I017852eac183fac3f914fdb96d7e72a56ea9d682 Reviewed-by: Nathanael Premillieu Reviewed-by: Andreas Sandberg Reviewed-on: https://gem5-review.googlesource.com/5121 Reviewed-by: Matthias Jung Reviewed-by: Jason Lowe-Power Maintainer: Andreas Sandberg --- src/cpu/o3/probe/elastic_trace.cc | 40 ++++++++++++++++++------------- 1 file changed, 24 insertions(+), 16 deletions(-) diff --git a/src/cpu/o3/probe/elastic_trace.cc b/src/cpu/o3/probe/elastic_trace.cc index 08ef6654d..508140e0c 100644 --- a/src/cpu/o3/probe/elastic_trace.cc +++ b/src/cpu/o3/probe/elastic_trace.cc @@ -238,23 +238,31 @@ ElasticTrace::updateRegDep(const DynInstPtr &dyn_inst) // dependency on the last writer. int8_t max_regs = dyn_inst->numSrcRegs(); for (int src_idx = 0; src_idx < max_regs; src_idx++) { - // Get the physical register index of the i'th source register. - PhysRegIdPtr src_reg = dyn_inst->renamedSrcRegIdx(src_idx); - DPRINTFR(ElasticTrace, "[sn:%lli] Check map for src reg" - " %i (%s)\n", seq_num, - src_reg->index(), src_reg->className()); - auto itr_last_writer = physRegDepMap.find(src_reg->flatIndex()); - if (itr_last_writer != physRegDepMap.end()) { - InstSeqNum last_writer = itr_last_writer->second; - // Additionally the dependency distance is kept less than the window - // size parameter to limit the memory allocation to nodes in the - // graph. If the window were tending to infinite we would have to - // load a large number of node objects during replay. - if (seq_num - last_writer < depWindowSize) { - // Record a physical register dependency. - exec_info_ptr->physRegDepSet.insert(last_writer); + + const RegId& src_reg = dyn_inst->srcRegIdx(src_idx); + if (!src_reg.isMiscReg() && + !src_reg.isZeroReg()) { + // Get the physical register index of the i'th source register. + PhysRegIdPtr phys_src_reg = dyn_inst->renamedSrcRegIdx(src_idx); + DPRINTFR(ElasticTrace, "[sn:%lli] Check map for src reg" + " %i (%s)\n", seq_num, + phys_src_reg->flatIndex(), phys_src_reg->className()); + auto itr_writer = physRegDepMap.find(phys_src_reg->flatIndex()); + if (itr_writer != physRegDepMap.end()) { + InstSeqNum last_writer = itr_writer->second; + // Additionally the dependency distance is kept less than the + // window size parameter to limit the memory allocation to + // nodes in the graph. If the window were tending to infinite + // we would have to load a large number of node objects during + // replay. + if (seq_num - last_writer < depWindowSize) { + // Record a physical register dependency. + exec_info_ptr->physRegDepSet.insert(last_writer); + } } + } + } // Loop through the destination registers of this instruction and update @@ -270,7 +278,7 @@ ElasticTrace::updateRegDep(const DynInstPtr &dyn_inst) // register. PhysRegIdPtr phys_dest_reg = dyn_inst->renamedDestRegIdx(dest_idx); DPRINTFR(ElasticTrace, "[sn:%lli] Update map for dest reg" - " %i (%s)\n", seq_num, dest_reg.index(), + " %i (%s)\n", seq_num, phys_dest_reg->flatIndex(), dest_reg.className()); physRegDepMap[phys_dest_reg->flatIndex()] = seq_num; } -- 2.30.2