linux-kernel - Re: [PATCH -tip v5 2/5] perf: set correct value to perf_event

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Date:	Mon, 30 Jan 2012 10:35:38 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Akihiro Nagai <akihiro.nagai.hw@...achi.com>
Cc:	Arnaldo Carvalho de Melo <acme@...radead.org>,
	Ingo Molnar <mingo@...e.hu>,
	Frederic Weisbecker <fweisbec@...il.com>,
	David Ahern <dsahern@...il.com>, linux-kernel@...r.kernel.org,
	Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>,
	yrl.pp-manager.tt@...achi.com, Paul Mackerras <paulus@...ba.org>
Subject: Re: [PATCH -tip v5 2/5] perf: set correct value to
 perf_event_header.misc for BTS

On Mon, 2012-01-30 at 13:43 +0900, Akihiro Nagai wrote:
> @@ -330,6 +342,14 @@ int intel_pmu_drain_bts_buffer(void)
>                 return 1;
>  
>         for (; at < top; at++) {
> +               /*
> +                * To resolve user space symbols and DSOs correctly, set
> +                * PERF_RECORD_MISC_USER if from_addr or to_addr is user space.
> +                */
> +               if (!kernel_ip(data.ip) || !kernel_ip(data.addr)) {
> +                       header.misc &= ~PERF_RECORD_MISC_CPUMODE_MASK;
> +                       header.misc |= PERF_RECORD_MISC_USER;
> +               }
>                 data.ip         = at->from;
>                 data.addr       = at->to; 

Why not key off of the from? If its a jump from userspace its a user
event, its a jump from kernel space its a kernel event?
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