linux-kernel - Re: [PATCH 6/6] perf tools: arm-spe: fix record hang after being terminated

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Date:   Wed, 15 Jan 2020 12:02:10 +0000
From:   James Clark <James.Clark@....com>
To:     Tan Xiaojun <tanxiaojun@...wei.com>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "acme@...nel.org" <acme@...nel.org>,
        "alexander.shishkin@...ux.intel.com" 
        <alexander.shishkin@...ux.intel.com>,
        "jolsa@...hat.com" <jolsa@...hat.com>,
        "namhyung@...nel.org" <namhyung@...nel.org>,
        "ak@...ux.intel.com" <ak@...ux.intel.com>,
        "adrian.hunter@...el.com" <adrian.hunter@...el.com>,
        "yao.jin@...ux.intel.com" <yao.jin@...ux.intel.com>,
        "tmricht@...ux.ibm.com" <tmricht@...ux.ibm.com>,
        "brueckner@...ux.ibm.com" <brueckner@...ux.ibm.com>,
        "songliubraving@...com" <songliubraving@...com>,
        "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
        Kim Phillips <Kim.Phillips@....com>,
        Jeremy Linton <Jeremy.Linton@....com>
CC:     "gengdongjiu@...wei.com" <gengdongjiu@...wei.com>,
        "wxf.wang@...ilicon.com" <wxf.wang@...ilicon.com>,
        "liwei391@...wei.com" <liwei391@...wei.com>,
        "liuqi115@...ilicon.com" <liuqi115@...ilicon.com>,
        "huawei.libin@...wei.com" <huawei.libin@...wei.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-perf-users@...r.kernel.org" <linux-perf-users@...r.kernel.org>,
        nd <nd@....com>
Subject: Re: [PATCH 6/6] perf tools: arm-spe: fix record hang after being
 terminated

Hi Xiaojun,

I've tested this and it all seems to be working OK. I only have one final change to propose, that if we unset precise_ip, along with this change 
http://lists.infradead.org/pipermail/linux-arm-kernel/2020-January/705720.html we will get feedback if an event is not supported in precise mode.

diff --git a/tools/perf/util/arm-spe.c b/tools/perf/util/arm-spe.c
index 0fcaefd386a6..a3c23d289482 100644
--- a/tools/perf/util/arm-spe.c
+++ b/tools/perf/util/arm-spe.c
@@ -937,6 +937,7 @@ void arm_spe_precise_ip_support(struct evlist *evlist, struct evsel *evsel)
                        evsel->core.attr.config = SPE_ATTR_TS_ENABLE
                                                | SPE_ATTR_BRANCH_FILTER;
                        evsel->core.attr.config1 = SPE_ATTR_EV_BRANCH;
+                        evsel->core.attr.precise_ip = 0;
                }
        }
 }

Thanks
James

On 18/12/2019 07:54, Tan Xiaojun wrote:
> From: Wei Li <liwei391@...wei.com>
> 
> If the spe event is terminated, we don't enable it again here.
> 
> Signed-off-by: Wei Li <liwei391@...wei.com>
> Tested-by: Qi Liu <liuqi115@...ilicon.com>
> ---
>  tools/perf/arch/arm64/util/arm-spe.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/tools/perf/arch/arm64/util/arm-spe.c b/tools/perf/arch/arm64/util/arm-spe.c
> index eba6541ec0f1..629badda724d 100644
> --- a/tools/perf/arch/arm64/util/arm-spe.c
> +++ b/tools/perf/arch/arm64/util/arm-spe.c
> @@ -165,9 +165,13 @@ static int arm_spe_read_finish(struct auxtrace_record *itr, int idx)
>  	struct evsel *evsel;
>  
>  	evlist__for_each_entry(sper->evlist, evsel) {
> -		if (evsel->core.attr.type == sper->arm_spe_pmu->type)
> -			return perf_evlist__enable_event_idx(sper->evlist,
> -							     evsel, idx);
> +		if (evsel->core.attr.type == sper->arm_spe_pmu->type) {
> +			if (evsel->terminated)
> +				return 0;
> +			else
> +				return perf_evlist__enable_event_idx(
> +						sper->evlist, evsel, idx);
> +		}
>  	}
>  	return -EINVAL;
>  }
>