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From: Vineet Gupta <Vineet.Gupta1@synopsys.com>
To: Lada Trimasova <Lada.Trimasova@synopsys.com>,
	"linux-perf-users@vger.kernel.org"
	<linux-perf-users@vger.kernel.org>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"peterz@infradead.org" <peterz@infradead.org>,
	Alexey Brodkin <Alexey.Brodkin@synopsys.com>,
	"linux-snps-arc@lists.infradead.org"
	<linux-snps-arc@lists.infradead.org>
Subject: Re: Misleading hint to select CONFIG_PERF_EVENTS if driver sets PERF_PMU_CAP_NO_INTERRUPT
Date: Thu, 28 Apr 2016 10:05:13 +0530	[thread overview]
Message-ID: <57219301.10505@synopsys.com> (raw)
In-Reply-To: <1461770030.5970.8.camel__5728.3871378333$1461770054$gmane$org@synopsys.com>

On Wednesday 27 April 2016 08:43 PM, Lada Trimasova wrote:
> On Tue, 2016-04-26 at 12:42 +0000, Vineet Gupta wrote:
> 
> On Friday 22 April 2016 06:56 PM, Lada Trimasova wrote:
> I think what we have now is sufficient - but u seem to want a prettier failure output.
> 
> Anyhow, this print is coming from util/evsel.c: perf_evsel__open_strerror()
> At the very least you want another entry in switch case for ENOTSUPP and then
> check if event was sampling one (
> evsel->attr.sample_period) - use that as a hint for saying sampling events not
> supported.
> 
> 
> 
> 
> ENOTSUPP is not visible for user programs. So it's impossible to add this entry
> 
> to mentioned switch.
> 
> I think that there is no good way to make error message more understandable
> 
> without breaking existing api.

I meant EOPNOTSUPP. Any errno value has to be visible to user programs otherwise
there is no point defining it.

WARNING: multiple messages have this Message-ID (diff)
From: Vineet.Gupta1@synopsys.com (Vineet Gupta)
To: linux-snps-arc@lists.infradead.org
Subject: Misleading hint to select CONFIG_PERF_EVENTS if driver sets PERF_PMU_CAP_NO_INTERRUPT
Date: Thu, 28 Apr 2016 10:05:13 +0530	[thread overview]
Message-ID: <57219301.10505@synopsys.com> (raw)
In-Reply-To: <1461770030.5970.8.camel__5728.3871378333$1461770054$gmane$org@synopsys.com>

On Wednesday 27 April 2016 08:43 PM, Lada Trimasova wrote:
> On Tue, 2016-04-26@12:42 +0000, Vineet Gupta wrote:
> 
> On Friday 22 April 2016 06:56 PM, Lada Trimasova wrote:
> I think what we have now is sufficient - but u seem to want a prettier failure output.
> 
> Anyhow, this print is coming from util/evsel.c: perf_evsel__open_strerror()
> At the very least you want another entry in switch case for ENOTSUPP and then
> check if event was sampling one (
> evsel->attr.sample_period) - use that as a hint for saying sampling events not
> supported.
> 
> 
> 
> 
> ENOTSUPP is not visible for user programs. So it's impossible to add this entry
> 
> to mentioned switch.
> 
> I think that there is no good way to make error message more understandable
> 
> without breaking existing api.

I meant EOPNOTSUPP. Any errno value has to be visible to user programs otherwise
there is no point defining it.

  parent reply	other threads:[~2016-04-28  4:35 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-04-22 13:25 Misleading hint to select CONFIG_PERF_EVENTS if driver sets PERF_PMU_CAP_NO_INTERRUPT Lada Trimasova
2016-04-22 13:25 ` Lada Trimasova
2016-04-26 10:57 ` Lada Trimasova
2016-04-26 10:57   ` Lada Trimasova
2016-04-26 12:42 ` Vineet Gupta
2016-04-26 12:42   ` Vineet Gupta
2016-04-27 15:13   ` Lada Trimasova
2016-04-27 15:13     ` Lada Trimasova
     [not found]   ` <1461770030.5970.8.camel__5728.3871378333$1461770054$gmane$org@synopsys.com>
2016-04-28  4:35     ` Vineet Gupta [this message]
2016-04-28  4:35       ` Vineet Gupta
2016-05-05 13:21   ` Vineet Gupta
2016-05-05 13:21     ` Vineet Gupta

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