Hello, I noticed this problem a few days ago. I was using se.py on O3CPU (ARM) with modified parameters, and I noticed that the simulation was extremely slow (According to the stats file in about 5 minutes less than 100 instructions were fetched.) I started testing each one of the processor parameters individually and found out that when I set cpu.numPhysFloatRegs to the lowest possible value this problem occurs. If I set it to anything more than the lowest possible value, it works at expected speeds.
Lower limit for the number of physical floating point registers is set by an assert statement in src/cpu/o3/cpu.cc: assert(params->numPhysFloatRegs >= numThreads * TheISA::NumFloatRegs); For ARM, NumFloatRegs is defined as 160 in src/arch/arm/registers.hh (128 NumFloatV8ArchRegs + 32 NumFloatSpecialRegs). When I set numPhysFloatRegs to 160 the simulation becomes impractically slow. When I set it to 161 or more, it goes back to normal speed. Is this a known problem? I haven't seen anything in the mailing list about it. Thanks. -Murat.
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