Messages in this thread | | | Subject | Re: [PATCH] iommu/amd: Fix event counter availability check | From | Shuah Khan <> | Date | Tue, 2 Jun 2020 17:51:59 -0600 |
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On 5/31/20 1:22 AM, Alexander Monakov wrote: > Hi, > > Adding Shuah Khan to Cc: I've noticed you've seen this issue on Ryzen 2400GE; > can you have a look at the patch? Would be nice to know if it fixes the > problem for you too. >
I am not seeing any change in behavior on my system. I still see:
I can't read perf counters.
The question I asked in my previous thread on this:
-------------------------------------------------------------------- I see 2 banks and 4 counters on my system. Is it sufficient to check the first bank and first counter? In other words, if the first one isn't writable, are all counters non-writable?
Should we read the config first and then, try to see if any of the counters are writable? I have a patch that does that, I can send it out for review.
I changed the logic to read config to get max banks and counters before checking if counters are writable and tried writing to all. The result is the same and all of them aren't writable. However, when disable the writable check and assume they are, I can run
perf stat -e 'amd_iommu_0 on all events and get data.
perf stat -e 'amd_iommu_0/cmd_processed/' sleep 10
Performance counter stats for 'system wide':
56 amd_iommu_0/cmd_processed/
10.001525171 seconds time elapsed
perf stat -a -e amd_iommu/mem_trans_total/ sleep 10
Performance counter stats for 'system wide':
2,696 amd_iommu/mem_trans_total/
10.001465115 seconds time elapsed
I tried all possible events listed under amd_iommu_0 and I can get data on all of them. No problems in dmesg. --------------------------------------------------------------------
This patch doesn't really address that question.
thanks, -- Shuah
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