Subject: Re: [PATCH v6 07/11] drivers: perf: hisi: Add support for Hisilicon
 SoC event counters
To: Mark Rutland <mark.rutland@arm.com>
References: <1489127311-112778-1-git-send-email-anurup.m@huawei.com>
 <20170321165252.GA29116@leverpostej> <58DCD47C.2010501@gmail.com>
 <20170330104607.GC16211@leverpostej>
Cc: will.deacon@arm.com, linux-kernel@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, anurup.m@huawei.com,
        zhangshaokun@hisilicon.com, tanxiaojun@huawei.com,
        xuwei5@hisilicon.com, sanil.kumar@hisilicon.com, john.garry@huawei.com,
        gabriele.paoloni@huawei.com, shiju.jose@huawei.com,
        huangdaode@hisilicon.com, linuxarm@huawei.com, dikshit.n@huawei.com,
        shyju.pv@huawei.com
From: Anurup M <anurupvasu@gmail.com>
Message-ID: <58DE6400.8030900@gmail.com>
Date: Fri, 31 Mar 2017 19:43:20 +0530
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On Thursday 30 March 2017 04:16 PM, Mark Rutland wrote:
>>>>> +	/*
>>>>> > >>>+	 * We must NOT create groups containing mixed PMUs, although
>>>>> > >>>+	 * software events are acceptable
>>>>> > >>>+	 */
>>>>> > >>>+	if (event->group_leader->pmu != event->pmu &&
>>>>> > >>>+	    !is_software_event(event->group_leader))
>>>>> > >>>+		return -EINVAL;
>>>>> > >>>+
>>>>> > >>>+	list_for_each_entry(sibling, &event->group_leader->sibling_list,
>>>>> > >>>+			    group_entry)
>>>>> > >>>+		if (sibling->pmu != event->pmu && !is_software_event(sibling))
>>>>> > >>>+			return -EINVAL;
>>> > >Please also check the number of counters.
>> >
>> >Sorry, I could not follow this comment correctly. Could you please explain ?
>> >I check the available counters and update used mask in pmu_add -->
>> >get_event_index
> What I meant was that here we should ensure that a group does not
> contain more events than can fit into counters.
>
> For example, if the HW had two counters, we should reject any group with
> more than two events. Such groups can never be scheduled, and make no
> sense.

I have referred drivers/bus/arm-cci.c and could find validate_group and 
validate_event functions,
which create a fake_pmu to check the available counters for the events 
in the group.
Is that the same way which is expected here? Please comment.

Thanks,
Anurup

> Thanks,
> Mark.