linux-kernel - Re: [PATCH v2 1/1] dmaengine: idxd: Add IDXD performance monitor support

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Message-ID: <34f61cc9-a6d6-e5a3-5f8c-6ffae8858cce@linux.intel.com>
Date:   Tue, 20 Apr 2021 09:13:20 -0500
From:   "Zanussi, Tom" <tom.zanussi@...ux.intel.com>
To:     Vinod Koul <vkoul@...nel.org>
Cc:     peterz@...radead.org, acme@...nel.org, mingo@...nel.org,
        kan.liang@...ux.intel.com, dave.jiang@...el.com,
        tony.luck@...el.com, dan.j.williams@...el.com,
        linux-kernel@...r.kernel.org, dmaengine@...r.kernel.org
Subject: Re: [PATCH v2 1/1] dmaengine: idxd: Add IDXD performance monitor
 support

Hi Vinod,

On 4/20/2021 6:11 AM, Vinod Koul wrote:
> On 03-04-21, 11:45, Tom Zanussi wrote:
> 
>> +config INTEL_IDXD_PERFMON
>> +	bool "Intel Data Accelerators performance monitor support"
>> +	depends on INTEL_IDXD
>> +	default y
> 
> default y..?

Will change to n.

> 
>>   /* IDXD software descriptor */
>> @@ -369,4 +399,19 @@ int idxd_cdev_get_major(struct idxd_device *idxd);
>>   int idxd_wq_add_cdev(struct idxd_wq *wq);
>>   void idxd_wq_del_cdev(struct idxd_wq *wq);
>>   
>> +/* perfmon */
>> +#ifdef CONFIG_INTEL_IDXD_PERFMON
> 
> maybe use IS_ENABLED()
> 
>> @@ -556,6 +562,8 @@ static int __init idxd_init_module(void)
>>   	for (i = 0; i < IDXD_TYPE_MAX; i++)
>>   		idr_init(&idxd_idrs[i]);
>>   
>> +	perfmon_init();
>> +
>>   	err = idxd_register_bus_type();
>>   	if (err < 0)
>>   		return err;
>> @@ -589,5 +597,6 @@ static void __exit idxd_exit_module(void)
>>   	pci_unregister_driver(&idxd_pci_driver);
>>   	idxd_cdev_remove();
>>   	idxd_unregister_bus_type();
>> +	perfmon_exit();
> 
> Ideally would make sense to add perfmon module first and then add use in
> idxd..
> 

OK, I'll separate this out into a separate patch.

>> +static ssize_t cpumask_show(struct device *dev, struct device_attribute *attr,
>> +			    char *buf);
>> +
>> +static cpumask_t		perfmon_dsa_cpu_mask;
>> +static bool			cpuhp_set_up;
>> +static enum cpuhp_state		cpuhp_slot;
>> +
>> +static DEVICE_ATTR_RO(cpumask);
> 
> Pls document these new attributes added
> 
>> +static int perfmon_collect_events(struct idxd_pmu *idxd_pmu,
>> +				  struct perf_event *leader,
>> +				  bool dogrp)
> 
> dogrp..?
> 

Yeah, bad name, first thought on seeing it is always 'dog'. ;-)

>> +static int perfmon_validate_group(struct idxd_pmu *pmu,
>> +				  struct perf_event *event)
>> +{
>> +	struct perf_event *leader = event->group_leader;
>> +	struct idxd_pmu *fake_pmu;
>> +	int i, ret = 0, n;
>> +
>> +	fake_pmu = kzalloc(sizeof(*fake_pmu), GFP_KERNEL);
>> +	if (!fake_pmu)
>> +		return -ENOMEM;
>> +
>> +	fake_pmu->pmu.name = pmu->pmu.name;
>> +	fake_pmu->n_counters = pmu->n_counters;
>> +
>> +	n = perfmon_collect_events(fake_pmu, leader, true);
>> +	if (n < 0) {
>> +		ret = n;
>> +		goto out;
>> +	}
>> +
>> +	fake_pmu->n_events = n;
>> +	n = perfmon_collect_events(fake_pmu, event, false);
>> +	if (n < 0) {
>> +		ret = n;
>> +		goto out;
>> +	}
>> +
>> +	fake_pmu->n_events = n;
>> +
>> +	for (i = 0; i < n; i++) {
>> +		int idx;
> 
> lets move it to top of the function please
> 
>> +static inline u64 perfmon_pmu_read_counter(struct perf_event *event)
>> +{
>> +	struct hw_perf_event *hwc = &event->hw;
>> +	struct idxd_device *idxd;
>> +	int cntr = hwc->idx;
>> +	u64 cntrdata;
>> +
>> +	idxd = event_to_idxd(event);
>> +
>> +	cntrdata = ioread64(CNTRDATA_REG(idxd, cntr));
>> +
>> +	return cntrdata;
> 
> return ioread64() ?
> 

Yeah, I removed some intervening code and didn't change this, will do.

Thanks for reviewing this,

Tom