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SubjectRe: [PATCH v4 2/3] Support for perf to probe into SDT markers:
On 10/29/2013 07:35 PM, Pekka Enberg wrote:
> On 10/29/2013 11:55 AM, Hemant Kumar wrote:
>> 1. Where this cache should be? Keeping it in tracing directory inside
>> the debugfs
>> directory should seem more feasible. And, shall this cache be shareable?
> You can't share all of the cache because otherwise you'll expose
> details on binaries that not everyone has access to.

Correct, that was one of the reason to be worried. And since, to a
normal user debugfs is not allowed to be entered, then we can keep that
inside debugfs/tracing subdirectory.

> It might make sense to split the cache into two parts: system markers
> and user markers and share the former.


>> 2. perf record is a performance intensive process, can we allow the
>> delay due to
>> this searching process here?
> I think scanning is OK if the user specified a SDT markers but not
> otherwise.
> Perhaps you can use a bloom filter to quickly check if the user passed
> a SDT marker or not.

True, bloom filters may help in this case with a quick check.

Hemant Kumar

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