Dear Gem5 Communities,
Here is the first few lines of stats.txt. While I am interpretating the
results, I came across several questions as follows. If you can share
knowleged on how to interpret these paraemters or any insight on the
computer architecture which relevant to these parameters, It will greately
help me out. Thank you for your help in advance,
1.
sim_freq 1000000000000
Is this meaning that I am running 1Thz CPU not 1Ghz? In order to run 1Ghz
core,
should I use --sys-clock=1000000000 flag in the gem5 command??
or since system.clk_domain.clock 1000, it supposed to be
2.
2-1 Why always sim_ops or host_op_rate always higher than sim_insts or
host_op_insts?
(looks like there is difference due to micro-ops, then what is micro-ops in
gem5 which introduces the dispcrency in numbers between insts and ops)
2-2 and what are those meaning?
2-3 why sim_insts/sim_ops can be signicantly higher value than
host_op_rate or sim_ops?
(Does this means one host ops/insts can simulated multiple of
sim_ops/insts?
3.
3-1 how come host_mem_usage is significantly smaller than
system.mem_ctrls.bytes_read::total or
system.mem_ctrls.bytes_written::total?? Does this means that not all the
data transaction in simulator get translated to
host memory transaction?
4. when I divide bytes_read::realview.clcd, cpu.dtb.walker, cpu.itb.walker,
cpu.inst, cpu.data by
num_reads::realview.clcd, cpu.dtb.walker, cpu.itb.walker, cpu.inst,
cpu.data are 8byte, 64byte, 64byte, 64byte, 27.037byte, respetively.
-> Does these exact integer form clcd bus size and cache line size? then,
why bytes_read::cpu.data/num_read:cpu.data isn't integer form?
5. When I looked at the bandwidth of realview.clcd, cpu.dtb.walker,
cpu.itb.walker, cpu.inst, cpu.data is about <200MB/sec.
What is limiting factor which results in seemingly significant lower
performance when we consider all these bus are on-chip bus.
Is this performance limited by spare read request so that its full memory
bandwidth isn't fully utilized?
6.
system.clk_domain.clock = 1000 # clock period in ticks while
system.cpu_clk_domain.clock = 500 # Clock period in ticks
what is these two differnet statement but similar imply?
7. In regards to membus
system.cf0.dma_read_full_pages, bytes, txs are all zeros. Why there is no
DMA access issued between disk and main memory? is this
because I didn't set configuraiton file properly? If so, which file shoudl
i take a look at ?
========================= Except from stats.txt ======================
sim_seconds 11.984008
# Number of seconds simulated
sim_ticks
11984008127500 # Number of ticks simulated
final_tick
21526428618000 # Number of ticks from beginning of
simulation (restored from checkpoints and never reset)
sim_freq
1000000000000 # Frequency of simulated ticks
host_inst_rate 3782675
# Simulator instruction rate (inst/s)
host_op_rate 4683852
# Simulator op (including micro ops) rate (op/s)
host_tick_rate 3275899922
# Simulator tick rate (ticks/s)
host_mem_usage 531428
# Number of bytes of host memory used
host_seconds 3658.23
# Real time elapsed on the host
sim_insts 13837909967
# Number of instructions simulated
sim_ops 17134626065
# Number of ops (including micro ops) simulated
system.voltage_domain.voltage 1
# Voltage in Volts
system.clk_domain.clock 1000
# Clock period in ticks
system.mem_ctrls.bytes_read::realview.clcd
575232000 # Number of bytes read from this memory
system.mem_ctrls.bytes_read::cpu.dtb.walker
15130432 # Number of bytes read from this memory
system.mem_ctrls.bytes_read::cpu.itb.walker
2436736 # Number of bytes read from this memory
system.mem_ctrls.bytes_read::cpu.inst 121968896
# Number of bytes read from this memory
system.mem_ctrls.bytes_read::cpu.data 1500576028
# Number of bytes read from this memory
system.mem_ctrls.bytes_read::total 2215344092
# Number of bytes read from this memory
system.mem_ctrls.bytes_inst_read::cpu.inst
121968896 # Number of instructions bytes read from
this memory
system.mem_ctrls.bytes_inst_read::total 121968896
# Number of instructions bytes read from this memory
system.mem_ctrls.bytes_written::writebacks
606101568 # Number of bytes written to this memory
system.mem_ctrls.bytes_written::cpu.data 179348570
# Number of bytes written to this memory
system.mem_ctrls.bytes_written::total 785450138
# Number of bytes written to this memory
system.mem_ctrls.num_reads::realview.clcd
71904000 # Number of read requests responded to by
this memory
system.mem_ctrls.num_reads::cpu.dtb.walker
236413 # Number of read requests responded to by this
memory
system.mem_ctrls.num_reads::cpu.itb.walker
38074 # Number of read requests responded to by this
memory
system.mem_ctrls.num_reads::cpu.inst 1905764
# Number of read requests responded to by this memory
system.mem_ctrls.num_reads::cpu.data 55499398
# Number of read requests responded to by this memory
system.mem_ctrls.num_reads::total 129583649
# Number of read requests responded to by this memory
system.mem_ctrls.num_writes::writebacks 9470337
# Number of write requests responded to by this memory
system.mem_ctrls.num_writes::cpu.data 84315511
# Number of write requests responded to by this memory
system.mem_ctrls.num_writes::total 93785848
# Number of write requests responded to by this memory
system.mem_ctrls.bw_read::realview.clcd 47999967
# Total read bandwidth from this memory (bytes/s)
system.mem_ctrls.bw_read::cpu.dtb.walker 1262552
# Total read bandwidth from this memory (bytes/s)
system.mem_ctrls.bw_read::cpu.itb.walker 203332
# Total read bandwidth from this memory (bytes/s)
system.mem_ctrls.bw_read::cpu.inst 10177638
# Total read bandwidth from this memory (bytes/s)
system.mem_ctrls.bw_read::cpu.data 125214871
# Total read bandwidth from this memory (bytes/s)
system.mem_ctrls.bw_read::total 184858360
# Total read bandwidth from this memory (bytes/s)
system.mem_ctrls.bw_inst_read::cpu.inst 10177638
# Instruction read bandwidth from this memory (bytes/s)
system.mem_ctrls.bw_inst_read::total 10177638
# Instruction read bandwidth from this memory (bytes/s)
system.mem_ctrls.bw_write::writebacks 50575864
# Write bandwidth from this memory (bytes/s)
system.mem_ctrls.bw_write::cpu.data 14965658
# Write bandwidth from this memory (bytes/s)
system.mem_ctrls.bw_write::total 65541522
# Write bandwidth from this memory (bytes/s)
system.mem_ctrls.bw_total::writebacks 50575864
# Total bandwidth to/from this memory (bytes/s)
system.mem_ctrls.bw_total::realview.clcd 47999967
# Total bandwidth to/from this memory (bytes/s)
system.mem_ctrls.bw_total::cpu.dtb.walker
1262552 # Total bandwidth to/from this memory
(bytes/s)
system.mem_ctrls.bw_total::cpu.itb.walker
203332 # Total bandwidth to/from this memory (bytes/s)
system.mem_ctrls.bw_total::cpu.inst 10177638
# Total bandwidth to/from this memory (bytes/s)
system.mem_ctrls.bw_total::cpu.data 140180529
# Total bandwidth to/from this memory (bytes/s)
system.mem_ctrls.bw_total::total 250399883
# Total bandwidth to/from this memory (bytes/s)
system.membus.throughput 272148492
# Throughput (bytes/s)
system.membus.data_through_bus 3261429746
# Total data (bytes)
system.membus.snoop_data_through_bus 0
# Total snoop data (bytes)
system.cpu_voltage_domain.voltage 1
# Voltage in Volts
system.cpu_clk_domain.clock 500
# Clock period in ticks
system.cf0.dma_read_full_pages 0
# Number of full page size DMA reads (not PRD).
system.cf0.dma_read_bytes 0
# Number of bytes transfered via DMA reads (not PRD).
system.cf0.dma_read_txs 0
# Number of DMA read transactions (not PRD).
system.cf0.dma_write_full_pages 0
# Number of full page size DMA writes.
system.cf0.dma_write_bytes 0
# Number of bytes transfered via DMA writes.
system.cf0.dma_write_txs 0
# Number of DMA write transactions.
system.cf2.dma_read_full_pages 0
# Number of full page size DMA reads (not PRD).
system.cf2.dma_read_bytes 0
# Number of bytes transfered via DMA reads (not PRD).
system.cf2.dma_read_txs 0
# Number of DMA read transactions (not PRD).
system.cf2.dma_write_full_pages 0
# Number of full page size DMA writes.
system.cf2.dma_write_bytes 0
# Number of bytes transfered via DMA writes.
system.cf2.dma_write_txs 0
# Number of DMA write transactions.
Thanks,
Regards
Kuk-Hwan
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