[RFC PATCH 6/6] arm_mpam: [NFU] Development diagnostics for MPAM ID assignments

Dave Martin Dave.Martin at arm.com
Thu Dec 12 07:40:00 PST 2024


Purely for development purposes, add some printks to show what MPAM
IDs actually get assigned and configured.

This would otherwise be observable only though statistical
measurements of performance (or not observable at all).

This change is not intended for upstream.

Signed-off-by: Dave Martin <Dave.Martin at arm.com>
---
 arch/arm64/include/asm/mpam.h              | 7 +++++++
 drivers/platform/arm64/mpam/mpam_devices.c | 6 ++++++
 2 files changed, 13 insertions(+)

diff --git a/arch/arm64/include/asm/mpam.h b/arch/arm64/include/asm/mpam.h
index df725d2d9d05..4ae2e635e261 100644
--- a/arch/arm64/include/asm/mpam.h
+++ b/arch/arm64/include/asm/mpam.h
@@ -66,6 +66,9 @@ static inline void mpam_set_cpu_defaults(int cpu, u16 partid_d, u16 partid_i,
 	default_val |= FIELD_PREP(MPAM1_EL1_PMG_I, pmg_i);
 
 	WRITE_ONCE(per_cpu(arm64_mpam_default, cpu), default_val);
+
+	pr_info("MPAM: CPU%d -> (D=%d:%d, I=%d:%d)\n",
+		cpu, partid_d, pmg_d, partid_i, pmg_i);
 }
 
 static inline void mpam_set_task_partid_pmg(struct task_struct *tsk,
@@ -81,6 +84,10 @@ static inline void mpam_set_task_partid_pmg(struct task_struct *tsk,
 	regval |= FIELD_PREP(MPAM1_EL1_PMG_I, pmg_i);
 
 	WRITE_ONCE(task_thread_info(tsk)->mpam_partid_pmg, regval);
+
+	pr_info("MPAM: task %s[%d/%d] -> (D=%d:%d, I=%d:%d)\n",
+		current->comm, current->pid, current->tgid,
+		partid_d, pmg_d, partid_i, pmg_i);
 #endif
 }
 
diff --git a/drivers/platform/arm64/mpam/mpam_devices.c b/drivers/platform/arm64/mpam/mpam_devices.c
index 41962dd1bb68..dd84c0aa50f6 100644
--- a/drivers/platform/arm64/mpam/mpam_devices.c
+++ b/drivers/platform/arm64/mpam/mpam_devices.c
@@ -3158,6 +3158,12 @@ int mpam_apply_config(struct mpam_component *comp, u16 partid,
 
 	mpam_extend_config(comp->class, cfg);
 
+	pr_info("mpam_apply_config(): comp %d partid %d cfg={0x%x: 0x%lx, 0x%lx, %u, %u}\n",
+		comp->comp_id, partid, cfg->features,
+		(unsigned long)cfg->cpbm,
+		(unsigned long)cfg->mbw_pbm,
+		cfg->mbw_min, cfg->mbw_max);
+
 	if (!mpam_update_config(&comp->cfg[partid], cfg))
 		return 0;
 
-- 
2.34.1




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