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Date:   Wed, 23 Nov 2022 12:35:42 -0600
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Reply-To: babu.moger@amd.com
Subject: Re: [PATCH v8 08/13] x86/resctrl: Add sysfs interface to read
 mbm_total_bytes_config
Content-Language: en-US
To:     Reinette Chatre <reinette.chatre@intel.com>, corbet@lwn.net,
        tglx@linutronix.de, mingo@redhat.com, bp@alien8.de
Cc:     fenghua.yu@intel.com, dave.hansen@linux.intel.com, x86@kernel.org,
        hpa@zytor.com, paulmck@kernel.org, akpm@linux-foundation.org,
        quic_neeraju@quicinc.com, rdunlap@infradead.org,
        damien.lemoal@opensource.wdc.com, songmuchun@bytedance.com,
        peterz@infradead.org, jpoimboe@kernel.org, pbonzini@redhat.com,
        chang.seok.bae@intel.com, pawan.kumar.gupta@linux.intel.com,
        jmattson@google.com, daniel.sneddon@linux.intel.com,
        sandipan.das@amd.com, tony.luck@intel.com, james.morse@arm.com,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        bagasdotme@gmail.com, eranian@google.com
References: <166759188265.3281208.11769277079826754455.stgit@bmoger-ubuntu>
 <166759205510.3281208.11437041392524040365.stgit@bmoger-ubuntu>
 <46d00211-e6e2-a0d9-22ca-ee0d3ca15468@intel.com>
From:   "Moger, Babu" <babu.moger@amd.com>
In-Reply-To: <46d00211-e6e2-a0d9-22ca-ee0d3ca15468@intel.com>
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Hi Reinette,


On 11/22/22 18:19, Reinette Chatre wrote:
> Hi Babu,
>
> On 11/4/2022 1:00 PM, Babu Moger wrote:
>> The current event configuration can be viewed by the user by reading
>> the configuration file /sys/fs/resctrl/info/L3_MON/mbm_total_bytes_config.
>> The event configuration settings are domain specific and will affect all
>> the CPUs in the domain.
>>
>> Following are the types of events supported:
>> ====  ===========================================================
>> Bits   Description
>> ====  ===========================================================
>> 6      Dirty Victims from the QOS domain to all types of memory
>> 5      Reads to slow memory in the non-local NUMA domain
>> 4      Reads to slow memory in the local NUMA domain
>> 3      Non-temporal writes to non-local NUMA domain
>> 2      Non-temporal writes to local NUMA domain
>> 1      Reads to memory in the non-local NUMA domain
>> 0      Reads to memory in the local NUMA domain
>> ====  ===========================================================
>>
>> By default, the mbm_total_bytes_config is set to 0x7f to count all the
>> event types.
>>
>> For example:
>>     $cat /sys/fs/resctrl/info/L3_MON/mbm_total_bytes_config
>>     0=0x7f;1=0x7f;2=0x7f;3=0x7f
>>
>>     In this case, the event mbm_total_bytes is currently configured
>>     with 0x7f on domains 0 to 3.
>>
>> Signed-off-by: Babu Moger <babu.moger@amd.com>
>> ---
>>  arch/x86/kernel/cpu/resctrl/internal.h |   28 ++++++++++
>>  arch/x86/kernel/cpu/resctrl/monitor.c  |    1 
>>  arch/x86/kernel/cpu/resctrl/rdtgroup.c |   87 ++++++++++++++++++++++++++++++++
>>  3 files changed, 116 insertions(+)
>>
>> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
>> index 5459b5022760..c74285fd0f6e 100644
>> --- a/arch/x86/kernel/cpu/resctrl/internal.h
>> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
>> @@ -15,6 +15,7 @@
>>  #define MSR_IA32_MBA_THRTL_BASE		0xd50
>>  #define MSR_IA32_MBA_BW_BASE		0xc0000200
>>  #define MSR_IA32_SMBA_BW_BASE		0xc0000280
>> +#define MSR_IA32_EVT_CFG_BASE		0xc0000400
>>  
>>  #define MSR_IA32_QM_CTR			0x0c8e
>>  #define MSR_IA32_QM_EVTSEL		0x0c8d
>> @@ -41,6 +42,32 @@
>>   */
>>  #define MBM_CNTR_WIDTH_OFFSET_MAX (62 - MBM_CNTR_WIDTH_BASE)
>>  
>> +/* Reads to Local DRAM Memory */
>> +#define READS_TO_LOCAL_MEM		BIT(0)
>> +
>> +/* Reads to Remote DRAM Memory */
>> +#define READS_TO_REMOTE_MEM		BIT(1)
>> +
>> +/* Non-Temporal Writes to Local Memory */
>> +#define NON_TEMP_WRITE_TO_LOCAL_MEM	BIT(2)
>> +
>> +/* Non-Temporal Writes to Remote Memory */
>> +#define NON_TEMP_WRITE_TO_REMOTE_MEM	BIT(3)
>> +
>> +/* Reads to Local Memory the system identifies as "Slow Memory" */
>> +#define READS_TO_LOCAL_S_MEM		BIT(4)
>> +
>> +/* Reads to Remote Memory the system identifies as "Slow Memory" */
>> +#define READS_TO_REMOTE_S_MEM		BIT(5)
>> +
>> +/* Dirty Victims to All Types of Memory */
>> +#define  DIRTY_VICTIMS_TO_ALL_MEM	BIT(6)
>> +
>> +/* Max event bits supported */
>> +#define MAX_EVT_CONFIG_BITS		GENMASK(6, 0)
>> +
>> +/* Max configurable events */
>> +#define MAX_CONFIG_EVENTS		2
>>  
> This max being disconnected from what it is a max of looks like
> a source of future confusion.

ok, Not required anymore with your suggested change below.  Will remove it.

>
>>  struct rdt_fs_context {
>>  	struct kernfs_fs_context	kfc;
>> @@ -542,5 +569,6 @@ bool has_busy_rmid(struct rdt_resource *r, struct rdt_domain *d);
>>  void __check_limbo(struct rdt_domain *d, bool force_free);
>>  void rdt_domain_reconfigure_cdp(struct rdt_resource *r);
>>  void __init thread_throttle_mode_init(void);
>> +void mbm_config_rftype_init(void);
>>  
>>  #endif /* _ASM_X86_RESCTRL_INTERNAL_H */
>> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
>> index 06c2dc980855..a188dacab6c8 100644
>> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
>> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
>> @@ -787,6 +787,7 @@ int rdt_get_mon_l3_config(struct rdt_resource *r)
>>  	if (mon_configurable) {
>>  		mbm_total_event.configurable = true;
>>  		mbm_local_event.configurable = true;
>> +		mbm_config_rftype_init();
>>  	}
>>  
>>  	l3_mon_evt_init(r);
>> diff --git a/arch/x86/kernel/cpu/resctrl/rdtgroup.c b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> index 8342feb54a7f..dea58b6b4aa4 100644
>> --- a/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> +++ b/arch/x86/kernel/cpu/resctrl/rdtgroup.c
>> @@ -1423,6 +1423,78 @@ static int rdtgroup_size_show(struct kernfs_open_file *of,
>>  	return ret;
>>  }
>>  
>> +struct mon_config_info {
>> +	u32 evtid;
>> +	u32 mon_config;
>> +};
>> +
>> +/**
>> + * mon_event_config_index_get - get the index for the configurable event
>> + * @evtid: event id.
>> + *
>> + * Return: 0 for evtid == QOS_L3_MBM_TOTAL_EVENT_ID
>> + *         1 for evtid == QOS_L3_MBM_LOCAL_EVENT_ID
>> + *         > 1 otherwise
>> + */
>> +static inline unsigned int mon_event_config_index_get(u32 evtid)
>> +{
>> +	return evtid - QOS_L3_MBM_TOTAL_EVENT_ID;
>> +}
> It seems strange that the validation of the index is split
> from where the index is determined. I think it would be easier
> to understand, and reduce code duplication, it if is done together.
>
> How about:
> #define INVALID_CONFIG_INDEX   UINT_MAX
>
> static inline unsigned int mon_event_config_index_get(u32 evtid)
> {
> 	switch (evtid) {
> 	case QOS_L3_MBM_TOTAL_EVENT_ID:
> 		return 0;
> 	case QOS_L3_MBM_LOCAL_EVENT_ID:
> 		return 1;
> 	default:
> 		/* WARN */
> 		return INVALID_CONFIG_INDEX;
> 	}
> }
>
> What do you think?
Yes. It should work
>
>> +
>> +static void mon_event_config_read(void *info)
>> +{
>> +	struct mon_config_info *mon_info = info;
>> +	u32 h, index;
>> +
>> +	index = mon_event_config_index_get(mon_info->evtid);
>> +	if (index >= MAX_CONFIG_EVENTS) {
>> +		pr_warn_once("Invalid event id %d\n", mon_info->evtid);
>> +		return;
>> +	}
>> +	rdmsr(MSR_IA32_EVT_CFG_BASE + index, mon_info->mon_config, h);
>> +}
>> +
>> +static void mondata_config_read(struct rdt_domain *d, struct mon_config_info *mon_info)
>> +{
>> +	smp_call_function_any(&d->cpu_mask, mon_event_config_read, mon_info, 1);
>> +}
>> +
>> +static int mbm_config_show(struct seq_file *s, struct rdt_resource *r, u32 evtid)
>> +{
>> +	struct mon_config_info mon_info = {0};
>> +	struct rdt_domain *dom;
>> +	bool sep = false;
>> +
>> +	mutex_lock(&rdtgroup_mutex);
>> +
>> +	list_for_each_entry(dom, &r->domains, list) {
>> +		if (sep)
>> +			seq_puts(s, ";");
>> +
>> +		mon_info.evtid = evtid;
>> +		mondata_config_read(dom, &mon_info);
>> +
>> +		seq_printf(s, "%d=0x%02lx", dom->id,
> This is a u32 ... is just x sufficient?

I have added 0x%02lx to silence the compiler. Not required anymore.


>
>> +			   mon_info.mon_config & MAX_EVT_CONFIG_BITS);
> Please do this masking within mondata_config_read(). It should
> not be required for every mon_config_read() caller to validate the
> data because they may forget (re. patch 10).
Sure. Will do.
>
>> +		sep = true;
>> +	}
>> +	seq_puts(s, "\n");
>> +
>> +	mutex_unlock(&rdtgroup_mutex);
>> +
>> +	return 0;
>> +}
>> +
>> +static int mbm_total_bytes_config_show(struct kernfs_open_file *of,
>> +				       struct seq_file *seq, void *v)
>> +{
>> +	struct rdt_resource *r = of->kn->parent->priv;
>> +
>> +	mbm_config_show(seq, r, QOS_L3_MBM_TOTAL_EVENT_ID);
>> +
>> +	return 0;
>> +}
>> +
>>  /* rdtgroup information files for one cache resource. */
>>  static struct rftype res_common_files[] = {
>>  	{
>> @@ -1521,6 +1593,12 @@ static struct rftype res_common_files[] = {
>>  		.seq_show	= max_threshold_occ_show,
>>  		.fflags		= RF_MON_INFO | RFTYPE_RES_CACHE,
>>  	},
>> +	{
>> +		.name		= "mbm_total_bytes_config",
>> +		.mode		= 0444,
>> +		.kf_ops		= &rdtgroup_kf_single_ops,
>> +		.seq_show	= mbm_total_bytes_config_show,
>> +	},
>>  	{
>>  		.name		= "cpus",
>>  		.mode		= 0644,
>> @@ -1627,6 +1705,15 @@ void __init thread_throttle_mode_init(void)
>>  	rft->fflags = RF_CTRL_INFO | RFTYPE_RES_MB;
>>  }
>>  
>> +void mbm_config_rftype_init(void)
> Does this need __init?

Not. Required. Will remove it.

Thanks

Babu

>
>> +{
>> +	struct rftype *rft;
>> +
>> +	rft = rdtgroup_get_rftype_by_name("mbm_total_bytes_config");
>> +	if (rft)
>> +		rft->fflags = RF_MON_INFO | RFTYPE_RES_CACHE;
>> +}
>> +
>>  /**
>>   * rdtgroup_kn_mode_restrict - Restrict user access to named resctrl file
>>   * @r: The resource group with which the file is associated.
>>
>>
> Reinette

-- 
Thanks
Babu Moger