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AmpereComputing / ampere-lts-kernel

Linux 5.4 and 5.10 Longterm kernel (LTS) with Ampere patches
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Some smmu pmu counter not work correctly #153

Open adamliyi opened 2 years ago

adamliyi commented 2 years ago

On latest kernel 5.17.0-rc8+.

200000000000-23ffdfffffff : PCI Bus 0002:00
  200000000000-2000001fffff : PCI Bus 0002:01
  200000200000-2000003fffff : PCI Bus 0002:02
  200000400000-2000005fffff : PCI Bus 0002:03
  200000600000-2000007fffff : PCI Bus 0002:04
23ffe0000000-23ffe001ffff : arm-smmu-v3.2.auto
  23ffe0000000-23ffe0000dff : arm-smmu-v3.2.auto
  23ffe0002000-23ffe0002fff : arm-smmu-v3-pmcg.36.auto
    23ffe0002000-23ffe0002fff : arm-smmu-v3-pmcg.36.auto arm-smmu-v3-pmcg.36.auto
  23ffe0010000-23ffe0010dff : arm-smmu-v3.2.auto
  23ffe0012000-23ffe0012fff : arm-smmu-v3-pmcg.36.auto
    23ffe0012000-23ffe0012fff : arm-smmu-v3-pmcg.36.auto arm-smmu-v3-pmcg.36.auto
23ffe0042000-23ffe0042fff : arm-smmu-v3-pmcg.26.auto
  23ffe0042000-23ffe0042fff : arm-smmu-v3-pmcg.26.auto arm-smmu-v3-pmcg.26.auto

Some pmu counter - the iomem region overlaps with SMMU, does not work properly:

# perf stat -e smmuv3_pmcg_23ffe0002/cycles/ -I 1000
#           time             counts unit events
     1.001051987         2147483649      smmuv3_pmcg_23ffe0002/cycles/
     2.002220614                  0      smmuv3_pmcg_23ffe0002/cycles/     <--------- ZERO value
     3.003272561                  0      smmuv3_pmcg_23ffe0002/cycles/
     4.004321628                  0      smmuv3_pmcg_23ffe0002/cycles/
     5.005364774                  0      smmuv3_pmcg_23ffe0002/cycles/

Other pmu counter works fine:

# perf stat -e smmuv3_pmcg_23ffe0042/cycles/ -I 1000
#           time             counts unit events
     1.001045667          500519737      smmuv3_pmcg_23ffe0042/cycles/
     2.002193934          500568588      smmuv3_pmcg_23ffe0042/cycles/  <--------- Non ZERO
     3.003245000          500523050      smmuv3_pmcg_23ffe0042/cycles/
     4.004290347          500523334      smmuv3_pmcg_23ffe0042/cycles/
     5.005341974          500524226      smmuv3_pmcg_23ffe0042/cycles/