From: Yicong Yang <yangyicong@huawei.com>
To: hejunhao <hejunhao3@huawei.com>, <mathieu.poirier@linaro.org>,
<suzuki.poulose@arm.com>, <jonathan.cameron@huawei.com>,
<corbet@lwn.net>, <linux-kernel@vger.kernel.org>,
<linux-doc@vger.kernel.org>
Cc: <yangyicong@hisilicon.com>, <alexander.shishkin@linux.intel.com>,
<helgaas@kernel.org>, <linux-pci@vger.kernel.org>,
<prime.zeng@huawei.com>
Subject: Re: [PATCH v4 4/5] hwtracing: hisi_ptt: Advertise PERF_PMU_CAP_NO_EXCLUDE for PTT PMU
Date: Tue, 20 Jun 2023 17:09:46 +0800 [thread overview]
Message-ID: <e3424908-a6a3-63f7-f3b7-e10b00cdfd13@huawei.com> (raw)
In-Reply-To: <01c39cb9-e56a-862b-2d99-024b7ba5a769@huawei.com>
Hi Junhao,
On 2023/6/19 21:00, hejunhao wrote:
> Hi, Yicong
>
>
> On 2023/6/6 22:22, Yicong Yang wrote:
>> From: Yicong Yang <yangyicong@hisilicon.com>
>>
>> The PTT trace collects PCIe TLP headers from the PCIe link and don't
>> have the ability to exclude certain context. It doesn't support itrace
>> as well. So only advertise PERF_PMU_CAP_NO_EXCLUDE. This will greatly
>> save the storage of final data. Tested tracing idle link for ~15s,
>> without this patch we'll collect ~28.682MB data for context related
>> information and with this patch it reduced to ~0.226MB.
>>
>> Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
>> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com>
>> ---
>> drivers/hwtracing/ptt/hisi_ptt.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/hwtracing/ptt/hisi_ptt.c b/drivers/hwtracing/ptt/hisi_ptt.c
>> index 5c7e93e7705f..ff2c16efe5b1 100644
>> --- a/drivers/hwtracing/ptt/hisi_ptt.c
>> +++ b/drivers/hwtracing/ptt/hisi_ptt.c
>> @@ -1210,7 +1210,7 @@ static int hisi_ptt_register_pmu(struct hisi_ptt *hisi_ptt)
>> hisi_ptt->hisi_ptt_pmu = (struct pmu) {
>> .module = THIS_MODULE,
>> - .capabilities = PERF_PMU_CAP_EXCLUSIVE | PERF_PMU_CAP_ITRACE,
>> + .capabilities = PERF_PMU_CAP_NO_EXCLUDE,
>
> According to the error prompt of function hisi_ptt_trace_start().
> https://elixir.bootlin.com/linux/v6.4-rc7/source/drivers/hwtracing/ptt/hisi_ptt.c#L197
>
> You may be need to keep advertise PERF_PMU_CAP_EXCLUSIVE?
> Such pmus can only have one event scheduled at a time, if not the perf
> tool will report device busy.
>
Thanks for point it out. Checking [1] I think we still need this flag here, will add
it back.
[1] https://github.com/torvalds/linux/blob/v6.4-rc6/kernel/events/core.c#L5054
Thanks.
next prev parent reply other threads:[~2023-06-20 9:09 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-06-06 14:22 [PATCH v4 0/5] Improve PTT filter interface and some fixes Yicong Yang
2023-06-06 14:22 ` [PATCH v4 1/5] hwtracing: hisi_ptt: Factor out filter allocation and release operation Yicong Yang
2023-06-06 14:22 ` [PATCH v4 2/5] hwtracing: hisi_ptt: Add support for dynamically updating the filter list Yicong Yang
2023-06-06 16:40 ` Jonathan Cameron
2023-06-06 14:22 ` [PATCH v4 3/5] hwtracing: hisi_ptt: Export available filters through sysfs Yicong Yang
2023-06-06 16:46 ` Jonathan Cameron
2023-06-06 14:22 ` [PATCH v4 4/5] hwtracing: hisi_ptt: Advertise PERF_PMU_CAP_NO_EXCLUDE for PTT PMU Yicong Yang
2023-06-19 13:00 ` hejunhao
2023-06-20 9:09 ` Yicong Yang [this message]
2023-06-06 14:22 ` [PATCH v4 5/5] hwtracing: hisi_ptt: Fix potential sleep in atomic context Yicong Yang
2023-06-06 16:43 ` Jonathan Cameron
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