Re: [PATCH v1 4/5] perf: Introduce address range filtering

From	Alexander Shishkin <alexander.shishkin@linux.intel.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v1 4/5] perf: Introduce address range filtering
Date	2016-04-25 18:20 +0200
Message-ID	<rrRoU-mn-39@gated-at.bofh.it> (permalink)
References	<rqoRX-2Wv-3@gated-at.bofh.it> <rqoRY-2Wv-33@gated-at.bofh.it> <rqE0G-6O2-29@gated-at.bofh.it> <rqLYe-4HV-13@gated-at.bofh.it> <rrPGq-7oh-17@gated-at.bofh.it>
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Peter Zijlstra <peterz@infradead.org> writes:

> On Fri, Apr 22, 2016 at 07:19:11PM +0300, Alexander Shishkin wrote:
>> +/*
>> + * Address range filtering: limiting the data to certain
>> + * instruction address ranges. Filters are ioctl()ed to us from
>> + * userspace as ascii strings.
>> + *
>> + * Filter string format:
>> + *
>> + * ACTION SOURCE:RANGE_SPEC
>> + * where ACTION is one of the
>> + *  * "filter": limit the trace to this region
>> + *  * "start": start tracing from this address
>> + *  * "stop": stop tracing at this address/region;
>> + * SOURCE is either "file" or "kernel"
>> + * RANGE_SPEC is
>> + *  * for "kernel": <start address>[/<size>]
>> + *  * for "file":   <start address>[/<size>]@</path/to/object/file>
>
> SOURCE seems entirely redundant

In the current state, yes, but if we wanted dedicated support for kernel
modules in filter definitions, it may come useful.

>> + *
>> + * if <size> is not specified, the range is treated as a single address.
>
> single instruction, right?

Yes, hitting that instruction will trigger tracing to start. PT doesn't
do this at the moment, but Coresight ETMs/PTMs do.

Regards,
--
Alex

Thread

[PATCH v1 4/5] perf: Introduce address range filtering Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-04-21 17:40 +0200
  Re: [PATCH v1 4/5] perf: Introduce address range filtering Peter Zijlstra <peterz@infradead.org> - 2016-04-22 09:50 +0200
    Re: [PATCH v1 4/5] perf: Introduce address range filtering Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-04-22 18:20 +0200
      Re: [PATCH v1 4/5] perf: Introduce address range filtering Peter Zijlstra <peterz@infradead.org> - 2016-04-25 15:00 +0200
        Re: [PATCH v1 4/5] perf: Introduce address range filtering Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-04-25 17:50 +0200
      Re: [PATCH v1 4/5] perf: Introduce address range filtering Peter Zijlstra <peterz@infradead.org> - 2016-04-25 15:20 +0200
        Re: [PATCH v1 4/5] perf: Introduce address range filtering Peter Zijlstra <peterz@infradead.org> - 2016-04-25 15:40 +0200
        Re: [PATCH v1 4/5] perf: Introduce address range filtering Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-04-25 18:10 +0200
      Re: [PATCH v1 4/5] perf: Introduce address range filtering Peter Zijlstra <peterz@infradead.org> - 2016-04-25 15:30 +0200
        Re: [PATCH v1 4/5] perf: Introduce address range filtering Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-04-25 18:10 +0200
      Re: [PATCH v1 4/5] perf: Introduce address range filtering Peter Zijlstra <peterz@infradead.org> - 2016-04-25 16:20 +0200
        Re: [PATCH v1 4/5] perf: Introduce address range filtering Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-04-25 18:10 +0200
      Re: [PATCH v1 4/5] perf: Introduce address range filtering Peter Zijlstra <peterz@infradead.org> - 2016-04-25 16:30 +0200
        Re: [PATCH v1 4/5] perf: Introduce address range filtering Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-04-25 18:20 +0200
        Re: [PATCH v1 4/5] perf: Introduce address range filtering Alexander Shishkin <alexander.shishkin@linux.intel.com> - 2016-04-26 16:40 +0200

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