I'm using HMC as my memory in my system. And I found a problem that once a simobject sent a read request, the latency of the response was different. I print out the DRAM trace. 1. if a read request is processed by dramctrl as follow, the latency is longer. 377334000: system.hmc_dev.mem_ctrls00: recvTimingReq: request PIMRead addr 1775248 size 8 377334000: system.hmc_dev.mem_ctrls00: Read queue limit 32, current size 0, entries needed 1 377334000: system.hmc_dev.mem_ctrls00: Address: 1775248 Rank 0 Bank 0 Row 3467 377334000: system.hmc_dev.mem_ctrls00: Read queue limit 32, current size 0, entries needed 1 377334000: system.hmc_dev.mem_ctrls00: Adding to read queue 377334000: system.hmc_dev.mem_ctrls00: Request scheduled immediately 377334000: system.hmc_dev.mem_ctrls00: QoS Turnarounds selected state READ 377334000: system.hmc_dev.mem_ctrls00: Single request, going to a busy rank 377334000: system.hmc_dev.mem_ctrls00: No Reads Found - exiting 2.if a read request is processed by dramctrl as follow, the latency is shorter. 344235000: system.hmc_dev.mem_ctrls00: recvTimingReq: request PIMRead addr 1774464 size 8 344235000: system.hmc_dev.mem_ctrls00: Read queue limit 32, current size 0, entries needed 1 344235000: system.hmc_dev.mem_ctrls00: Address: 1774464 Rank 0 Bank 0 Row 3465 344235000: system.hmc_dev.mem_ctrls00: Read queue limit 32, current size 0, entries needed 1 344235000: system.hmc_dev.mem_ctrls00: Adding to read queue 344235000: system.hmc_dev.mem_ctrls00: Request scheduled immediately 344235000: system.hmc_dev.mem_ctrls00: QoS Turnarounds selected state READ 344235000: system.hmc_dev.mem_ctrls00: Single request, going to a free rank 344235000: system.hmc_dev.mem_ctrls00: Timing access to addr 1774464, rank/bank/row 0 0 3465 344235000: system.hmc_dev.mem_ctrls00: Activate at tick 344241000 344235000: system.hmc_dev.mem_ctrls00: Activate bank 0, rank 0 at tick 344241000, now got 1 active 344235000: system.hmc_dev.mem_ctrls00: Access to 1774464, ready at 344264300 next burst at 344254400. 344235000: system.hmc_dev.mem_ctrls00: Precharging bank 0, rank 0 at tick 344262600, now got 0 active 344235000: system.hmc_dev.mem_ctrls00: Auto-precharged bank: 0
I think the point is Single request, going to a free or busy rank. I want to know in which case the rank is busy and why latency is different. _______________________________________________ gem5-users mailing list -- gem5-users@gem5.org To unsubscribe send an email to gem5-users-le...@gem5.org %(web_page_url)slistinfo%(cgiext)s/%(_internal_name)s
