linux-kernel - Re: [PATCH V7 1/4] perf/core: Add PERF_SAMPLE_DATA_PAGE

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Message-ID: <88177517-da0c-43d9-4f5c-fb610e66b9e0@linux.intel.com>
Date:   Thu, 17 Sep 2020 18:16:15 -0400
From:   "Liang, Kan" <kan.liang@...ux.intel.com>
To:     Dave Hansen <dave.hansen@...el.com>, peterz@...radead.org,
        mingo@...hat.com, acme@...nel.org, linux-kernel@...r.kernel.org
Cc:     mark.rutland@....com, alexander.shishkin@...ux.intel.com,
        jolsa@...hat.com, eranian@...gle.com, ak@...ux.intel.com,
        kirill.shutemov@...ux.intel.com, mpe@...erman.id.au,
        benh@...nel.crashing.org, paulus@...ba.org
Subject: Re: [PATCH V7 1/4] perf/core: Add PERF_SAMPLE_DATA_PAGE_SIZE



On 9/17/2020 6:02 PM, Dave Hansen wrote:
>> The problem is that the warning from the perf tool usually includes some
>> hints regarding the cause of the warning or possible solution to
>> workaround/fix the warning. What message should we deliver to the users?
>> "Warning: Too many error page size. Address space isolation feature may
>> be enabled, please check"?
> That's not particularly actionable for an end user.  Do any of the perf
> errors just tell them to submit a bug report?  "Excessive number of page
> size lookup errors, please report to..."

Yes, found some perf tool warnings end with "Consider reporting to 
linux-kernel@...r.kernel.org."

I will add a warning "Excessive number of page size lookup errors, 
please report to linux-kernel@...r.kernel.org.", if 90% of the samples 
have the page size 0.

Thanks,
Kan