From: Dave Hansen <dave.hansen@intel.com>
To: "Liang, Kan" <kan.liang@linux.intel.com>,
peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
linux-kernel@vger.kernel.org
Cc: mark.rutland@arm.com, alexander.shishkin@linux.intel.com,
jolsa@redhat.com, eranian@google.com, ak@linux.intel.com,
kirill.shutemov@linux.intel.com, mpe@ellerman.id.au,
benh@kernel.crashing.org, paulus@samba.org
Subject: Re: [PATCH V7 1/4] perf/core: Add PERF_SAMPLE_DATA_PAGE_SIZE
Date: Thu, 17 Sep 2020 15:02:58 -0700 [thread overview]
Message-ID: <39dd016a-b0ee-c9da-dc21-1b7175e8b5ef@intel.com> (raw)
In-Reply-To: <0e2cd6e4-8016-ccf6-eaff-2b304cf966ee@linux.intel.com>
On 9/17/20 2:58 PM, Liang, Kan wrote:
> The user space perf tool looks like a better place for this kind of
> warning. The perf tool knows the total number of the samples. It also
> knows the number of the page size 0 samples. We can set a threshold,
> e.g., 90%. If 90% of the samples have the page size 0, perf tool will
> throw out a warning message.
Sounds good to me.
> 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..."
next prev parent reply other threads:[~2020-09-17 22:03 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-17 13:52 [PATCH V7 0/4] Add the page size in the perf record (kernel) kan.liang
2020-09-17 13:52 ` [PATCH V7 1/4] perf/core: Add PERF_SAMPLE_DATA_PAGE_SIZE kan.liang
2020-09-17 19:00 ` Dave Hansen
2020-09-17 21:16 ` Liang, Kan
[not found] ` <04f59f3b-2e53-8774-8333-63dfc5b8e6a9@intel.com>
2020-09-17 21:58 ` Liang, Kan
2020-09-17 22:02 ` Dave Hansen [this message]
2020-09-17 22:16 ` Liang, Kan
2020-09-17 13:52 ` [PATCH V7 2/4] perf/x86/intel: Support PERF_SAMPLE_DATA_PAGE_SIZE kan.liang
2020-09-17 13:52 ` [PATCH V7 3/4] powerpc/perf: " kan.liang
2020-09-17 13:52 ` [PATCH V7 4/4] perf/core: Add support for PERF_SAMPLE_CODE_PAGE_SIZE kan.liang
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