linux-kernel - Re: [PATCH/RFC v3] perf core: Allow setting up max frame stack depth via sysctl

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20160426221017.GQ3430@twins.programming.kicks-ass.net>
Date:	Wed, 27 Apr 2016 00:10:17 +0200
From:	Peter Zijlstra <peterz@...radead.org>
To:	Brendan Gregg <brendan.d.gregg@...il.com>
Cc:	Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>,
	Alexei Starovoitov <alexei.starovoitov@...il.com>,
	David Ahern <dsahern@...il.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Alexei Starovoitov <ast@...nel.org>,
	He Kuang <hekuang@...wei.com>, Jiri Olsa <jolsa@...hat.com>,
	Masami Hiramatsu <mhiramat@...nel.org>,
	Milian Wolff <milian.wolff@...b.com>,
	Namhyung Kim <namhyung@...nel.org>,
	Stephane Eranian <eranian@...gle.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Vince Weaver <vincent.weaver@...ne.edu>,
	Wang Nan <wangnan0@...wei.com>, Zefan Li <lizefan@...wei.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH/RFC v3] perf core: Allow setting up max frame stack depth
 via sysctl

On Tue, Apr 26, 2016 at 02:58:41PM -0700, Brendan Gregg wrote:
> BTS seemed more promising (deeper stacks), and there's already Xen
> support for it (need to boot the Xen host with vpmu=bts, preferably
> vpmu=bts,arch for some PMCs as well :).

BTS is a branch tracer; it simply traces _all_ branches, including
calls. It has fairly significant overhead.

But yes, by tracing all branches, you should get really shiny call
traces :-)