Commit 79d7c3dc authored by Robin Murphy's avatar Robin Murphy Committed by Will Deacon
Browse files

perf/arm-cmn: Fix PMU instance naming 



Although it's neat to avoid the suffix for the typical case of a
single PMU, it means systems with multiple CMN instances end up with
inconsistent naming. I think it also breaks perf tool's "uncore alias"
logic if the common instance prefix is also the full name of one.

Avoid any surprises by not trying to be clever and simply numbering
every instance, even when it might technically prove redundant.

Fixes: 0ba64770 ("perf: Add Arm CMN-600 PMU driver")
Signed-off-by: default avatarRobin Murphy <robin.murphy@arm.com>
Link: https://lore.kernel.org/r/649a2281233f193d59240b13ed91b57337c77b32.1611839564.git.robin.murphy@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent f0c14048

Documentation/admin-guide/perf/arm-cmn.rst

+1 −1
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ PMU events 
----------



The PMU driver registers a single PMU device for the whole interconnect,

see /sys/bus/event_source/devices/arm_cmn. Multi-chip systems may link

see /sys/bus/event_source/devices/arm_cmn_0. Multi-chip systems may link

more than one CMN together via external CCIX links - in this situation,

each mesh counts its own events entirely independently, and additional

PMU devices will be named arm_cmn_{1..n}.

drivers/perf/arm-cmn.c

+4 −9
Original line number Diff line number Diff line
@@ -1502,7 +1502,7 @@ static int arm_cmn_probe(struct platform_device *pdev) 
	struct arm_cmn *cmn;

	const char *name;

	static atomic_t id;

	int err, rootnode, this_id;

	int err, rootnode;



	cmn = devm_kzalloc(&pdev->dev, sizeof(*cmn), GFP_KERNEL);

	if (!cmn)
@@ -1549,14 +1549,9 @@ static int arm_cmn_probe(struct platform_device *pdev) 
		.cancel_txn = arm_cmn_end_txn,

	};



	this_id = atomic_fetch_inc(&id);

	if (this_id == 0) {

		name = "arm_cmn";

	} else {

		name = devm_kasprintf(cmn->dev, GFP_KERNEL, "arm_cmn_%d", this_id);

	name = devm_kasprintf(cmn->dev, GFP_KERNEL, "arm_cmn_%d", atomic_fetch_inc(&id));

	if (!name)

		return -ENOMEM;

	}



	err = cpuhp_state_add_instance(arm_cmn_hp_state, &cmn->cpuhp_node);

	if (err)