Commit dc2005d4 authored by James Morse's avatar James Morse Committed by Zeng Heng
Browse files

untested: arm_mpam: resctrl: Add support for mbm counters 

maillist inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I8T2RT

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/morse/linux.git/log/?h=mpam/snapshot/v6.7-rc2



---------------------------

resctrl has two types of counters, NUMA-local and global. MPAM has only
bandwidth counters, but the position of the MSC may mean it counts
NUMA-local, or global traffic.

But the topology information is not available.

Apply a hueristic: the L2 or L3 supports bandwidth monitors, these are
probably NUMA-local. If the memory controller supports bandwidth
monitors, they are probably global.

This selection is made from mpam_resctrl_resource_init(), which
implies resources that can be used for resctrl controls exist and
also have counters. This would be a problem on a platform that only
supports monitoring.

TODO: Add an extra pass of all classes to find the classes to use
as bandwidth counters.

Signed-off-by: default avatarJames Morse <james.morse@arm.com>
Signed-off-by: default avatarZeng Heng <zengheng4@huawei.com>
parent 58db5c68

drivers/platform/mpam/mpam_resctrl.c

+51 −1
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ static struct mpam_resctrl_res mpam_resctrl_exports[RDT_NUM_RESOURCES]; 
static bool exposed_alloc_capable;

static bool exposed_mon_capable;

static struct mpam_class *mbm_local_class;

static struct mpam_class *mbm_total_class;



/*

 * MPAM emulates CDP by setting different PARTID in the I/D fields of MPAM1_EL1.
@@ -53,6 +54,11 @@ bool resctrl_arch_is_mbm_local_enabled(void) 
	return mbm_local_class;

}



bool resctrl_arch_is_mbm_total_enabled(void)

{

	return mbm_total_class;

}



bool resctrl_arch_get_cdp_enabled(enum resctrl_res_level rid)

{

	switch (rid) {
@@ -264,6 +270,24 @@ bool resctrl_arch_is_llc_occupancy_enabled(void) 
	return cache_has_usable_csu(mpam_resctrl_exports[RDT_RESOURCE_L3].class);

}



static bool class_has_usable_mbwu(struct mpam_class *class)

{

	struct mpam_props *cprops = &class->props;



	if (!mpam_has_feature(mpam_feat_msmon_mbwu, cprops))

		return false;



	/*

	 * resctrl expects the bandwidth counters to be free running,

	 * which means we need as many monitors as resctrl has

	 * control/monitor groups.

	 */

	if (cprops->num_mbwu_mon < resctrl_arch_system_num_rmid_idx())

		return false;



	return (mpam_partid_max > 1) || (mpam_pmg_max != 0);

}



static bool mba_class_use_mbw_part(struct mpam_props *cprops)

{

	/* TODO: Scaling is not yet supported */
@@ -449,10 +473,13 @@ static int mpam_resctrl_resource_init(struct mpam_resctrl_res *res) 
{

	struct mpam_class *class = res->class;

	struct rdt_resource *r = &res->resctrl_res;

	bool has_mbwu = class_has_usable_mbwu(class);



	/* Is this one of the two well-known caches? */

	if (res->resctrl_res.rid == RDT_RESOURCE_L2 ||

	    res->resctrl_res.rid == RDT_RESOURCE_L3) {

		bool has_csu = cache_has_usable_csu(class);



		/* TODO: Scaling is not yet supported */

		r->cache.cbm_len = class->props.cpbm_wd;

		r->cache.arch_has_sparse_bitmasks = true;
@@ -479,8 +506,25 @@ static int mpam_resctrl_resource_init(struct mpam_resctrl_res *res) 
			exposed_alloc_capable = true;

		}



		if (class->level == 3 && cache_has_usable_csu(class))

		/*

		 * MBWU counters may be 'local' or 'total' depending on where

		 * they are in the topology. Counters on caches are assumed to

		 * be local. If it's on the memory controller, its assumed to

		 * be global.

		 */

		if (has_mbwu && class->level >= 3) {

			mbm_local_class = class;

			r->mon_capable = true;

		}



		/*

		 * CSU counters only make sense on a cache. The file is called

		 * llc_occupancy, but its expected to the on the L3.

		 */

		if (has_csu && class->type == MPAM_CLASS_CACHE &&

		    class->level == 3) {

			r->mon_capable = true;

		}

	} else if (res->resctrl_res.rid == RDT_RESOURCE_MBA) {

		struct mpam_props *cprops = &class->props;
@@ -502,6 +546,11 @@ static int mpam_resctrl_resource_init(struct mpam_resctrl_res *res) 
			r->alloc_capable = true;

			exposed_alloc_capable = true;

		}



		if (has_mbwu && class->type == MPAM_CLASS_MEMORY) {

			mbm_total_class = class;

			r->mon_capable = true;

		}

	}



	if (r->mon_capable) {
@@ -537,6 +586,7 @@ int mpam_resctrl_setup(void) 


	mpam_resctrl_pick_caches();

	mpam_resctrl_pick_mba();

	/* TODO: mpam_resctrl_pick_counters(); */



	for (i = 0; i < RDT_NUM_RESOURCES; i++) {

		res = &mpam_resctrl_exports[i];

include/linux/arm_mpam.h

+1 −5
Original line number Diff line number Diff line
@@ -55,11 +55,7 @@ bool resctrl_arch_alloc_capable(void); 
bool resctrl_arch_mon_capable(void);

bool resctrl_arch_is_llc_occupancy_enabled(void);

bool resctrl_arch_is_mbm_local_enabled(void);



static inline bool resctrl_arch_is_mbm_total_enabled(void)

{

	return false;

}

bool resctrl_arch_is_mbm_total_enabled(void);



/* reset cached configurations, then all devices */

void resctrl_arch_reset_resources(void);