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From: David Ahern <dsahern@gmail.com>
To: Ingo Molnar <mingo@kernel.org>,
	Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
	Vince Weaver <vince@deater.net>,
	Stephane Eranian <eranian@google.com>,
	Jiri Olsa <jolsa@redhat.com>,
	Andy Lutomirski <luto@amacapital.net>,
	Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [RFD] perf syscall error handling
Date: Mon, 10 Nov 2014 07:14:19 -0700	[thread overview]
Message-ID: <5460C83B.5050905@gmail.com> (raw)
In-Reply-To: <20141110122446.GA21503@gmail.com>

On 11/10/14, 5:24 AM, Ingo Molnar wrote:
> Programmatic use in user-spaec is very simple - go with my
> initial example, tooling can either just display the error string
> and bail out, or do:
>
>    if (unlikely(error)) {
> 	if (!strcmp(attr->error_str, "x86/bts: BTS not supported by this CPU architecture")) {
> 		fprintf(stderr, "x86/BTS: No hardware support falling back to branch sampling\n");
> 		activate_x86_bts_fallback_code();
> 		goto out;
> 	}

That makes the exact string content part of the ABI. As I recall ftrace 
had a problem with format strings changing and tooling then limiting the 
ability to change it.

David

  parent reply	other threads:[~2014-11-10 14:14 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-10-30 22:28 [RFD] perf syscall error handling Peter Zijlstra
2014-10-31  1:16 ` Vince Weaver
2014-10-31  7:21   ` Peter Zijlstra
2014-10-31  9:27     ` Ingo Molnar
2014-10-31 12:28       ` Matt Fleming
2014-10-31 21:22         ` Stephane Eranian
2014-11-01  5:30           ` Vince Weaver
2014-11-03 16:25             ` Arnaldo Carvalho de Melo
2014-11-03 16:50               ` Peter Zijlstra
2014-11-03 17:00                 ` Arnaldo Carvalho de Melo
2014-11-03 17:12                   ` Vince Weaver
2014-11-03 17:39                     ` Peter Zijlstra
2014-11-10 10:27                   ` Ingo Molnar
2014-11-10 12:15                     ` Arnaldo Carvalho de Melo
2014-11-10 12:24                       ` Ingo Molnar
2014-11-10 13:54                         ` Arnaldo Carvalho de Melo
2014-11-10 14:14                         ` David Ahern [this message]
2014-11-10 14:47                           ` Ingo Molnar
2014-11-10 10:38           ` Ingo Molnar
2014-10-31 10:00   ` Arnaldo Carvalho de Melo

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