[PATCH v4 4/4] perf/marvell: cn10k DDR perf event core ownership
From: Bharat Bhushan <bbhushan2@marvell.com>
Date: 2021-09-20 05:09:01
Also in:
linux-arm-kernel, lkml
Subsystem:
arm pmu profiling and debugging, cpu hotplug, the rest · Maintainers:
Will Deacon, Mark Rutland, Thomas Gleixner, Peter Zijlstra, Linus Torvalds
As DDR perf event counters are not per core, so they should be accessed only by one core at a time. Select new core when previously owning core is going offline. Signed-off-by: Bharat Bhushan <bbhushan2@marvell.com> --- v1->v2->v3->v4: - No change drivers/perf/marvell_cn10k_ddr_pmu.c | 50 ++++++++++++++++++++++++++-- include/linux/cpuhotplug.h | 1 + 2 files changed, 49 insertions(+), 2 deletions(-)
diff --git a/drivers/perf/marvell_cn10k_ddr_pmu.c b/drivers/perf/marvell_cn10k_ddr_pmu.c
index 21fccb9090c5..bef0cee3a46a 100644
--- a/drivers/perf/marvell_cn10k_ddr_pmu.c
+++ b/drivers/perf/marvell_cn10k_ddr_pmu.c@@ -129,6 +129,7 @@ struct cn10k_ddr_pmu { int active_events; struct perf_event *events[DDRC_PERF_NUM_COUNTERS]; struct hrtimer hrtimer; + struct hlist_node node; }; #define to_cn10k_ddr_pmu(p) container_of(p, struct cn10k_ddr_pmu, pmu)
@@ -610,6 +611,24 @@ static enum hrtimer_restart cn10k_ddr_pmu_timer_handler(struct hrtimer *hrtimer) return HRTIMER_RESTART; } +static int cn10k_ddr_pmu_offline_cpu(unsigned int cpu, struct hlist_node *node) +{ + struct cn10k_ddr_pmu *pmu = hlist_entry_safe(node, struct cn10k_ddr_pmu, + node); + unsigned int target; + + if (cpu != pmu->cpu) + return 0; + + target = cpumask_any_but(cpu_online_mask, cpu); + if (target >= nr_cpu_ids) + return 0; + + perf_pmu_migrate_context(&pmu->pmu, cpu, target); + pmu->cpu = target; + return 0; +} + static int cn10k_ddr_perf_probe(struct platform_device *pdev) { struct cn10k_ddr_pmu *ddr_pmu;
@@ -661,18 +680,31 @@ static int cn10k_ddr_perf_probe(struct platform_device *pdev) hrtimer_init(&ddr_pmu->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); ddr_pmu->hrtimer.function = cn10k_ddr_pmu_timer_handler; + cpuhp_state_add_instance_nocalls( + CPUHP_AP_PERF_ARM_MARVELL_CN10K_DDR_ONLINE, + &ddr_pmu->node); + ret = perf_pmu_register(&ddr_pmu->pmu, name, -1); if (ret) - return ret; + goto error; pr_info("CN10K DDR PMU Driver for ddrc@%llx\n", res->start); return 0; +error: + cpuhp_state_remove_instance_nocalls( + CPUHP_AP_PERF_ARM_MARVELL_CN10K_DDR_ONLINE, + &ddr_pmu->node); + return ret; } static int cn10k_ddr_perf_remove(struct platform_device *pdev) { struct cn10k_ddr_pmu *ddr_pmu = platform_get_drvdata(pdev); + cpuhp_state_remove_instance_nocalls( + CPUHP_AP_PERF_ARM_MARVELL_CN10K_DDR_ONLINE, + &ddr_pmu->node); + perf_pmu_unregister(&ddr_pmu->pmu); return 0; }
@@ -695,12 +727,26 @@ static struct platform_driver cn10k_ddr_pmu_driver = { static int __init cn10k_ddr_pmu_init(void) { - return platform_driver_register(&cn10k_ddr_pmu_driver); + int ret; + + ret = cpuhp_setup_state_multi( + CPUHP_AP_PERF_ARM_MARVELL_CN10K_DDR_ONLINE, + "perf/marvell/cn10k/ddr:online", NULL, + cn10k_ddr_pmu_offline_cpu); + if (ret) + return ret; + + ret = platform_driver_register(&cn10k_ddr_pmu_driver); + if (ret) + cpuhp_remove_multi_state( + CPUHP_AP_PERF_ARM_MARVELL_CN10K_DDR_ONLINE); + return ret; } static void __exit cn10k_ddr_pmu_exit(void) { platform_driver_unregister(&cn10k_ddr_pmu_driver); + cpuhp_remove_multi_state(CPUHP_AP_PERF_ARM_MARVELL_CN10K_DDR_ONLINE); } module_init(cn10k_ddr_pmu_init);
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 832d8a74fa59..a4b521f12b58 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h@@ -227,6 +227,7 @@ enum cpuhp_state { CPUHP_AP_PERF_ARM_QCOM_L3_ONLINE, CPUHP_AP_PERF_ARM_APM_XGENE_ONLINE, CPUHP_AP_PERF_ARM_CAVIUM_TX2_UNCORE_ONLINE, + CPUHP_AP_PERF_ARM_MARVELL_CN10K_DDR_ONLINE, CPUHP_AP_PERF_POWERPC_NEST_IMC_ONLINE, CPUHP_AP_PERF_POWERPC_CORE_IMC_ONLINE, CPUHP_AP_PERF_POWERPC_THREAD_IMC_ONLINE,
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2.17.1