Re: [gem5-users] Increasing TLB size not working for X86 with O3CPU
Hi, Jason Sorry for my unclear description before. For our workload, the switch_cpus.dtb's miss rate for 64 tlb entries is 154654 / 1589214 = 9.74%; the miss rate for 1048576 tlb entries is 154360 / 1583757 = 9.73%. Both are running for 20ms warm up in atomic mode and 2.5ms real simulation with O3CPU. They are practically identical and very high especially for 1048576 entries with only 1MB heap size. Any idea or suggestions? Please let me know if other statistics or config information will be helpful. best, Da On Mon, May 28, 2018 at 12:03 PM, Jason Lowe-Power wrote: > Hi Da, > > "For size > 512, the whole stats.txt is identical." > > This isn't surprising. 512*4KB = 2MB. So, if your workload is only 1MB > when you have at least 512 entries you are only seeing compulsory (cold) > misses. Try running larger workloads and/or workloads with more reuse. > > Cheers, > Jason > > On Thu, May 24, 2018 at 9:11 AM Da Zhang wrote: > >> I am using FS mode. >> >> On Thu, May 24, 2018 at 12:00 PM, Jason Lowe-Power >> wrote: >> >>> Hi Da, >>> >>> Are you using SE mode or FS mode? IIRC, the TLB size does nothing in SE >>> mode (it doesn't use a TLB). The TLB is only used in FS mode. >>> >>> Jason >>> >>> On Thu, May 24, 2018 at 8:45 AM Da Zhang wrote: >>> Hey guys, I tried to increase the dtb size (i.e., number of tlb entries) for our research. However, the stats.txt for the different dtb size (64,128,256,512,1024,2048,1048576) is practical identical or identical. For size < 512, the system.switch_cpus.dtb.rdAccesses difference is only several hundred. For size > 512, the whole stats.txt is identical. I am working for the X86 architecture. I change the size in X86TLB.py to increase the dtb size. By checking the config.ini file, I see the size is set as expected (under system.cpu.dtb). Any clue? Thanks in advance. Best, Da ___ gem5-users mailing list gem5-users@gem5.org http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >>> >>> >>> ___ >>> gem5-users mailing list >>> gem5-users@gem5.org >>> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >>> >> >> ___ >> gem5-users mailing list >> gem5-users@gem5.org >> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users > > > ___ > gem5-users mailing list > gem5-users@gem5.org > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users > ___ gem5-users mailing list gem5-users@gem5.org http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
Re: [gem5-users] Increasing TLB size not working for X86 with O3CPU
Hi Da, "For size > 512, the whole stats.txt is identical." This isn't surprising. 512*4KB = 2MB. So, if your workload is only 1MB when you have at least 512 entries you are only seeing compulsory (cold) misses. Try running larger workloads and/or workloads with more reuse. Cheers, Jason On Thu, May 24, 2018 at 9:11 AM Da Zhang wrote: > I am using FS mode. > > On Thu, May 24, 2018 at 12:00 PM, Jason Lowe-Power > wrote: > >> Hi Da, >> >> Are you using SE mode or FS mode? IIRC, the TLB size does nothing in SE >> mode (it doesn't use a TLB). The TLB is only used in FS mode. >> >> Jason >> >> On Thu, May 24, 2018 at 8:45 AM Da Zhang wrote: >> >>> Hey guys, >>> >>> I tried to increase the dtb size (i.e., number of tlb entries) for our >>> research. However, the stats.txt for the different dtb size >>> (64,128,256,512,1024,2048,1048576) is practical identical or identical. For >>> size < 512, the system.switch_cpus.dtb.rdAccesses difference is only >>> several hundred. For size > 512, the whole stats.txt is identical. I am >>> working for the X86 architecture. I change the size in X86TLB.py to >>> increase the dtb size. By checking the config.ini file, I see the size is >>> set as expected (under system.cpu.dtb). Any clue? >>> >>> Thanks in advance. >>> >>> Best, >>> Da >>> >>> >>> ___ >>> gem5-users mailing list >>> gem5-users@gem5.org >>> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >> >> >> ___ >> gem5-users mailing list >> gem5-users@gem5.org >> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users >> > > ___ > gem5-users mailing list > gem5-users@gem5.org > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users ___ gem5-users mailing list gem5-users@gem5.org http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
Re: [gem5-users] Increasing TLB size not working for X86 with O3CPU
I am using FS mode. On Thu, May 24, 2018 at 12:00 PM, Jason Lowe-Power wrote: > Hi Da, > > Are you using SE mode or FS mode? IIRC, the TLB size does nothing in SE > mode (it doesn't use a TLB). The TLB is only used in FS mode. > > Jason > > On Thu, May 24, 2018 at 8:45 AM Da Zhang wrote: > >> Hey guys, >> >> I tried to increase the dtb size (i.e., number of tlb entries) for our >> research. However, the stats.txt for the different dtb size >> (64,128,256,512,1024,2048,1048576) is practical identical or identical. >> For size < 512, the system.switch_cpus.dtb.rdAccesses difference is only >> several hundred. For size > 512, the whole stats.txt is identical. I am >> working for the X86 architecture. I change the size in X86TLB.py to >> increase the dtb size. By checking the config.ini file, I see the size is >> set as expected (under system.cpu.dtb). Any clue? >> >> Thanks in advance. >> >> Best, >> Da >> >> >> ___ >> gem5-users mailing list >> gem5-users@gem5.org >> http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users > > > ___ > gem5-users mailing list > gem5-users@gem5.org > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users > ___ gem5-users mailing list gem5-users@gem5.org http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
Re: [gem5-users] Increasing TLB size not working for X86 with O3CPU
More details: The dtb read miss rate stays at 10%. Our workload is a simple sequential linked list search microbenchmark with fixed heap size at 1MB. Cache size is varied from 128KB to 2MB. On Thu, May 24, 2018 at 11:44 AM, Da Zhang wrote: > Hey guys, > > I tried to increase the dtb size (i.e., number of tlb entries) for our > research. However, the stats.txt for the different dtb size > (64,128,256,512,1024,2048,1048576) is practical identical or identical. > For size < 512, the system.switch_cpus.dtb.rdAccesses difference is only > several hundred. For size > 512, the whole stats.txt is identical. I am > working for the X86 architecture. I change the size in X86TLB.py to > increase the dtb size. By checking the config.ini file, I see the size is > set as expected (under system.cpu.dtb). Any clue? > > Thanks in advance. > > Best, > Da > > > ___ gem5-users mailing list gem5-users@gem5.org http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
Re: [gem5-users] Increasing TLB size not working for X86 with O3CPU
Hi Da, Are you using SE mode or FS mode? IIRC, the TLB size does nothing in SE mode (it doesn't use a TLB). The TLB is only used in FS mode. Jason On Thu, May 24, 2018 at 8:45 AM Da Zhang wrote: > Hey guys, > > I tried to increase the dtb size (i.e., number of tlb entries) for our > research. However, the stats.txt for the different dtb size > (64,128,256,512,1024,2048,1048576) is practical identical or identical. For > size < 512, the system.switch_cpus.dtb.rdAccesses difference is only > several hundred. For size > 512, the whole stats.txt is identical. I am > working for the X86 architecture. I change the size in X86TLB.py to > increase the dtb size. By checking the config.ini file, I see the size is > set as expected (under system.cpu.dtb). Any clue? > > Thanks in advance. > > Best, > Da > > > ___ > gem5-users mailing list > gem5-users@gem5.org > http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users ___ gem5-users mailing list gem5-users@gem5.org http://m5sim.org/cgi-bin/mailman/listinfo/gem5-users
