From: Peter Zijlstra <peterz@infradead.org>
To: "Wangnan (F)" <wangnan0@huawei.com>
Cc: Ingo Molnar <mingo@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
David Ahern <dsahern@gmail.com>,
Milian Wolff <milian.wolff@kdab.com>,
linux-kernel@vger.kernel.org, pi3orama <pi3orama@163.com>,
lizefan 00213767 <lizefan@huawei.com>
Subject: Re: [BUG REPORT] perf tools: x86_64: Broken calllchain when sampling taken at 'callq' instruction
Date: Thu, 19 Nov 2015 12:28:50 +0100 [thread overview]
Message-ID: <20151119112850.GM3816@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <564DA7C2.8060002@huawei.com>
On Thu, Nov 19, 2015 at 06:43:14PM +0800, Wangnan (F) wrote:
> Also, why not fixing rsp in kernel if that instruction is a 'callq'?
> For avoiding instruction decoding?
Why would the kernel do that? It doesn't need this.
Have userspace do it when trying to interpret the data.
If PERF_EFLAGS_EXACT is set, you know the IP points to the actual
instruction and you can attempt to undo whatever parts of it you need at
post processing time.
next prev parent reply other threads:[~2015-11-19 11:29 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-18 7:20 Wangnan (F)
2015-11-18 8:00 ` Wangnan (F)
2015-11-18 8:20 ` Ingo Molnar
2015-11-18 8:42 ` Wangnan (F)
2015-11-18 8:49 ` Wangnan (F)
2015-11-19 6:37 ` Ingo Molnar
2015-11-19 6:45 ` Wangnan (F)
2015-11-19 10:23 ` Ingo Molnar
2015-11-19 10:43 ` Wangnan (F)
2015-11-19 11:28 ` Peter Zijlstra [this message]
2015-11-19 11:23 ` Peter Zijlstra
2015-11-27 8:38 ` Ingo Molnar
2015-11-30 9:28 ` Peter Zijlstra
2015-12-01 7:28 ` Ingo Molnar
2015-12-01 8:38 ` Peter Zijlstra
2015-12-01 16:11 ` Ingo Molnar
2015-12-01 17:21 ` Peter Zijlstra
2015-12-02 9:55 ` Ingo Molnar
2015-11-18 8:48 ` Jiri Olsa
2015-11-18 9:02 ` Wangnan (F)
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