RE: [EXT] Re: [PATCH 1/2] drivers: perf: Add LLC-TAD perf counter support
From: Bhaskara Budiredla
Date: Tue Aug 17 2021 - 06:07:18 EST
Thanks Kajol for pointing to memory leak.
I will fix it in the next version.
Thanks,
Bhaskara
>-----Original Message-----
>From: kajoljain <kjain@xxxxxxxxxxxxx>
>Sent: Saturday, August 14, 2021 7:24 PM
>To: Bhaskara Budiredla <bbudiredla@xxxxxxxxxxx>; will@xxxxxxxxxx;
>mark.rutland@xxxxxxx; robh+dt@xxxxxxxxxx; Sunil Kovvuri Goutham
><sgoutham@xxxxxxxxxxx>
>Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
>kernel@xxxxxxxxxxxxxxx
>Subject: [EXT] Re: [PATCH 1/2] drivers: perf: Add LLC-TAD perf counter support
>
>External Email
>
>----------------------------------------------------------------------
>
>
>On 8/12/21 11:12 PM, Bhaskara Budiredla wrote:
>> This driver adds support for Last-level cache tag-and-data unit
>> (LLC-TAD) PMU that is featured in some of the Marvell's CN10K
>> infrastructure silicons.
>>
>> The LLC is divided into 2N slices distributed across N Mesh tiles in a
>> single-socket configuration. The driver always configures the same
>> counter for all of the TADs. The user would end up effectively
>> reserving one of eight counters in every TAD to look across all TADs.
>> The occurrences of events are aggregated and presented to the user at
>> the end of an application run. The driver does not provide a way for
>> the user to partition TADs so that different TADs are used for
>> different applications.
>>
>> The event counters are zeroed on start event counting to avoid any
>> rollover issues. TAD perf counters are 64-bit, so it's not currently
>> possible to overflow event counters at current mesh and core
>> frequencies.
>>
>> To measure tad pmu events use perf tool stat command. For instance:
>>
>> perf stat -e tad_dat_msh_in_dss,tad_req_msh_out_any <application> perf
>> stat -e tad_alloc_any,tad_hit_any,tad_tag_rd <application>
>>
>> Signed-off-by: Bhaskara Budiredla <bbudiredla@xxxxxxxxxxx>
>> ---
>> drivers/perf/Kconfig | 7 +
>> drivers/perf/Makefile | 1 +
>> drivers/perf/marvell_cn10k_tad_pmu.c | 429
>> +++++++++++++++++++++++++++
>> 3 files changed, 437 insertions(+)
>> create mode 100644 drivers/perf/marvell_cn10k_tad_pmu.c
>>
>> diff --git a/drivers/perf/Kconfig b/drivers/perf/Kconfig index
>> 77522e5efe11..73dca11f8080 100644
>> --- a/drivers/perf/Kconfig
>> +++ b/drivers/perf/Kconfig
>> @@ -137,6 +137,13 @@ config ARM_DMC620_PMU
>> Support for PMU events monitoring on the ARM DMC-620 memory
>> controller.
>>
>> +config MARVELL_CN10K_TAD_PMU
>> + tristate "Marvell CN10K LLC-TAD PMU"
>> + depends on ARM64
>> + help
>> + Provides support for Last-Level cache Tag-and-data Units (LLC-TAD)
>> + performance monitors on CN10K family silicons.
>> +
>> source "drivers/perf/hisilicon/Kconfig"
>>
>> endmenu
>> diff --git a/drivers/perf/Makefile b/drivers/perf/Makefile index
>> 5260b116c7da..2db5418d5b0a 100644
>> --- a/drivers/perf/Makefile
>> +++ b/drivers/perf/Makefile
>> @@ -14,3 +14,4 @@ obj-$(CONFIG_THUNDERX2_PMU) +=
>thunderx2_pmu.o
>> obj-$(CONFIG_XGENE_PMU) += xgene_pmu.o
>> obj-$(CONFIG_ARM_SPE_PMU) += arm_spe_pmu.o
>> obj-$(CONFIG_ARM_DMC620_PMU) += arm_dmc620_pmu.o
>> +obj-$(CONFIG_MARVELL_CN10K_TAD_PMU) += marvell_cn10k_tad_pmu.o
>> diff --git a/drivers/perf/marvell_cn10k_tad_pmu.c
>> b/drivers/perf/marvell_cn10k_tad_pmu.c
>> new file mode 100644
>> index 000000000000..fec8b90d52d2
>> --- /dev/null
>> +++ b/drivers/perf/marvell_cn10k_tad_pmu.c
>> @@ -0,0 +1,429 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/* Marvell CN10K LLC-TAD perf driver
>> + *
>> + * Copyright (C) 2021 Marvell.
>> + *
>> + * This program is free software; you can redistribute it and/or
>> +modify
>> + * it under the terms of the GNU General Public License version 2 as
>> + * published by the Free Software Foundation.
>> + */
>> +
>> +#define pr_fmt(fmt) "tad_pmu: " fmt
>> +
>> +#include <linux/module.h>
>> +#include <linux/of.h>
>> +#include <linux/of_address.h>
>> +#include <linux/of_device.h>
>> +#include <linux/cpuhotplug.h>
>> +#include <linux/perf_event.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/arm-smccc.h>
>> +
>> +#define TAD_PFC_OFFSET 0x0800
>> +#define TAD_PFC(counter) (TAD_PFC_OFFSET | (counter << 3))
>> +#define TAD_PRF_OFFSET 0x0900
>> +#define TAD_PRF(counter) (TAD_PRF_OFFSET | (counter << 3))
>> +#define TAD_PRF_CNTSEL_MASK 0xFF
>> +#define TAD_MAX_COUNTERS 8
>> +
>> +#define to_tad_pmu(p) (container_of(p, struct tad_pmu, pmu))
>> +
>> +struct tad_region {
>> + void __iomem *base;
>> +};
>> +
>> +struct tad_pmu {
>> + struct pmu pmu;
>> + struct tad_region *regions;
>> + u32 region_cnt;
>> + unsigned int cpu;
>> + struct hlist_node node;
>> + struct perf_event *events[TAD_MAX_COUNTERS];
>> + DECLARE_BITMAP(counters_map, TAD_MAX_COUNTERS); };
>> +
>> +static int tad_pmu_cpuhp_state;
>> +
>> +static void tad_pmu_event_counter_read(struct perf_event *event) {
>> + struct tad_pmu *tad_pmu = to_tad_pmu(event->pmu);
>> + struct hw_perf_event *hwc = &event->hw;
>> + u32 counter_idx = hwc->idx;
>> + u64 delta, prev, new;
>> + int i;
>> +
>> + do {
>> + prev = local64_read(&hwc->prev_count);
>> + for (i = 0, new = 0; i < tad_pmu->region_cnt; i++)
>> + new += readq(tad_pmu->regions[i].base +
>> + TAD_PFC(counter_idx));
>> + } while (local64_cmpxchg(&hwc->prev_count, prev, new) != prev);
>> +
>> + delta = (new - prev) & GENMASK_ULL(63, 0);
>> + local64_add(delta, &event->count);
>> +}
>> +
>> +static void tad_pmu_event_counter_stop(struct perf_event *event, int
>> +flags) {
>> + struct tad_pmu *tad_pmu = to_tad_pmu(event->pmu);
>> + struct hw_perf_event *hwc = &event->hw;
>> + u32 counter_idx = hwc->idx;
>> + int i;
>> +
>> + /* TAD()_PFC() stop counting on the write
>> + * which sets TAD()_PRF()[CNTSEL] == 0
>> + */
>> + for (i = 0; i < tad_pmu->region_cnt; i++)
>> + writeq_relaxed(0, tad_pmu->regions[i].base +
>> + TAD_PRF(counter_idx));
>> +
>> + tad_pmu_event_counter_read(event);
>> + hwc->state |= PERF_HES_STOPPED | PERF_HES_UPTODATE; }
>> +
>> +static void tad_pmu_event_counter_start(struct perf_event *event, int
>> +flags) {
>> + struct tad_pmu *tad_pmu = to_tad_pmu(event->pmu);
>> + struct hw_perf_event *hwc = &event->hw;
>> + u32 event_idx = event->attr.config;
>> + u32 counter_idx = hwc->idx;
>> + u64 reg_val;
>> + int i;
>> +
>> + hwc->state = 0;
>> +
>> + /* Typically TAD_PFC() are zeroed to start counting */
>> + for (i = 0; i < tad_pmu->region_cnt; i++)
>> + writeq_relaxed(0, tad_pmu->regions[i].base +
>> + TAD_PFC(counter_idx));
>> +
>> + /* TAD()_PFC() start counting on the write
>> + * which sets TAD()_PRF()[CNTSEL] != 0
>> + */
>> + for (i = 0; i < tad_pmu->region_cnt; i++) {
>> + reg_val = readq_relaxed(tad_pmu->regions[i].base +
>> + TAD_PRF(counter_idx));
>> + reg_val |= (event_idx & 0xFF);
>> + writeq_relaxed(reg_val, tad_pmu->regions[i].base +
>> + TAD_PRF(counter_idx));
>> + }
>> +}
>> +
>> +static void tad_pmu_event_counter_del(struct perf_event *event, int
>> +flags) {
>> + struct tad_pmu *tad_pmu = to_tad_pmu(event->pmu);
>> + struct hw_perf_event *hwc = &event->hw;
>> + int idx = hwc->idx;
>> +
>> + tad_pmu_event_counter_stop(event, flags | PERF_EF_UPDATE);
>> + tad_pmu->events[idx] = NULL;
>> + clear_bit(idx, tad_pmu->counters_map); }
>> +
>> +static int tad_pmu_event_counter_add(struct perf_event *event, int
>> +flags) {
>> + struct tad_pmu *tad_pmu = to_tad_pmu(event->pmu);
>> + struct hw_perf_event *hwc = &event->hw;
>> + int idx;
>> +
>> + /* Get a free counter for this event */
>> + idx = find_first_zero_bit(tad_pmu->counters_map,
>TAD_MAX_COUNTERS);
>> + if (idx == TAD_MAX_COUNTERS)
>> + return -EAGAIN;
>> +
>> + set_bit(idx, tad_pmu->counters_map);
>> +
>> + hwc->idx = idx;
>> + hwc->state = PERF_HES_STOPPED;
>> + tad_pmu->events[idx] = event;
>> +
>> + if (flags & PERF_EF_START)
>> + tad_pmu_event_counter_start(event, flags);
>> +
>> + return 0;
>> +}
>> +
>> +static int tad_pmu_event_init(struct perf_event *event) {
>> + struct tad_pmu *tad_pmu = to_tad_pmu(event->pmu);
>> +
>> + if (!event->attr.disabled)
>> + return -EINVAL;
>> +
>> + if (event->attr.type != event->pmu->type)
>> + return -ENOENT;
>> +
>> + if (event->state != PERF_EVENT_STATE_OFF)
>> + return -EINVAL;
>> +
>> + event->cpu = tad_pmu->cpu;
>> + event->hw.idx = -1;
>> + event->hw.config_base = event->attr.config;
>> +
>> + return 0;
>> +}
>> +
>> +static ssize_t tad_pmu_event_show(struct device *dev,
>> + struct device_attribute *attr, char *page) {
>> + struct perf_pmu_events_attr *pmu_attr;
>> +
>> + pmu_attr = container_of(attr, struct perf_pmu_events_attr, attr);
>> + return sprintf(page, "event=0x%02llx\n", pmu_attr->id); }
>> +
>> +#define TAD_PMU_EVENT_ATTR(name, config) \
>> + PMU_EVENT_ATTR_ID(name, tad_pmu_event_show, config)
>> +
>> +static struct attribute *tad_pmu_event_attrs[] = {
>> + TAD_PMU_EVENT_ATTR(tad_none, 0x0),
>> + TAD_PMU_EVENT_ATTR(tad_req_msh_in_any, 0x1),
>> + TAD_PMU_EVENT_ATTR(tad_req_msh_in_mn, 0x2),
>> + TAD_PMU_EVENT_ATTR(tad_req_msh_in_exlmn, 0x3),
>> + TAD_PMU_EVENT_ATTR(tad_rsp_msh_in_any, 0x4),
>> + TAD_PMU_EVENT_ATTR(tad_rsp_msh_in_mn, 0x5),
>> + TAD_PMU_EVENT_ATTR(tad_rsp_msh_in_exlmn, 0x6),
>> + TAD_PMU_EVENT_ATTR(tad_rsp_msh_in_dss, 0x7),
>> + TAD_PMU_EVENT_ATTR(tad_rsp_msh_in_retry_dss, 0x8),
>> + TAD_PMU_EVENT_ATTR(tad_dat_msh_in_any, 0x9),
>> + TAD_PMU_EVENT_ATTR(tad_dat_msh_in_dss, 0xa),
>> + TAD_PMU_EVENT_ATTR(tad_req_msh_out_any, 0xb),
>> + TAD_PMU_EVENT_ATTR(tad_req_msh_out_dss_rd, 0xc),
>> + TAD_PMU_EVENT_ATTR(tad_req_msh_out_dss_wr, 0xd),
>> + TAD_PMU_EVENT_ATTR(tad_req_msh_out_evict, 0xe),
>> + TAD_PMU_EVENT_ATTR(tad_rsp_msh_out_any, 0xf),
>> + TAD_PMU_EVENT_ATTR(tad_rsp_msh_out_retry_exlmn, 0x10),
>> + TAD_PMU_EVENT_ATTR(tad_rsp_msh_out_retry_mn, 0x11),
>> + TAD_PMU_EVENT_ATTR(tad_rsp_msh_out_exlmn, 0x12),
>> + TAD_PMU_EVENT_ATTR(tad_rsp_msh_out_mn, 0x13),
>> + TAD_PMU_EVENT_ATTR(tad_snp_msh_out_any, 0x14),
>> + TAD_PMU_EVENT_ATTR(tad_snp_msh_out_mn, 0x15),
>> + TAD_PMU_EVENT_ATTR(tad_snp_msh_out_exlmn, 0x16),
>> + TAD_PMU_EVENT_ATTR(tad_dat_msh_out_any, 0x17),
>> + TAD_PMU_EVENT_ATTR(tad_dat_msh_out_fill, 0x18),
>> + TAD_PMU_EVENT_ATTR(tad_dat_msh_out_dss, 0x19),
>> + TAD_PMU_EVENT_ATTR(tad_alloc_dtg, 0x1a),
>> + TAD_PMU_EVENT_ATTR(tad_alloc_ltg, 0x1b),
>> + TAD_PMU_EVENT_ATTR(tad_alloc_any, 0x1c),
>> + TAD_PMU_EVENT_ATTR(tad_hit_dtg, 0x1d),
>> + TAD_PMU_EVENT_ATTR(tad_hit_ltg, 0x1e),
>> + TAD_PMU_EVENT_ATTR(tad_hit_any, 0x1f),
>> + TAD_PMU_EVENT_ATTR(tad_tag_rd, 0x20),
>> + TAD_PMU_EVENT_ATTR(tad_dat_rd, 0x21),
>> + TAD_PMU_EVENT_ATTR(tad_dat_rd_byp, 0x22),
>> + TAD_PMU_EVENT_ATTR(tad_ifb_occ, 0x23),
>> + TAD_PMU_EVENT_ATTR(tad_req_occ, 0x24),
>> + NULL,
>> +};
>> +
>> +static const struct attribute_group tad_pmu_events_attr_group = {
>> + .name = "events",
>> + .attrs = tad_pmu_event_attrs,
>> +};
>> +
>> +PMU_FORMAT_ATTR(event, "config:0-7");
>> +
>> +static struct attribute *tad_pmu_format_attrs[] = {
>> + &format_attr_event.attr,
>> + NULL,
>> +};
>> +
>> +static struct attribute_group tad_pmu_format_attr_group = {
>> + .name = "format",
>> + .attrs = tad_pmu_format_attrs,
>> +};
>> +
>> +static ssize_t tad_pmu_cpumask_show(struct device *dev,
>> + struct device_attribute *attr, char *buf) {
>> + struct tad_pmu *tad_pmu = to_tad_pmu(dev_get_drvdata(dev));
>> +
>> + return cpumap_print_to_pagebuf(true, buf, cpumask_of(tad_pmu-
>>cpu));
>> +}
>> +
>> +static DEVICE_ATTR(cpumask, 0444, tad_pmu_cpumask_show, NULL);
>> +
>> +static struct attribute *tad_pmu_cpumask_attrs[] = {
>> + &dev_attr_cpumask.attr,
>> + NULL,
>> +};
>> +
>> +static struct attribute_group tad_pmu_cpumask_attr_group = {
>> + .attrs = tad_pmu_cpumask_attrs,
>> +};
>> +
>> +static const struct attribute_group *tad_pmu_attr_groups[] = {
>> + &tad_pmu_events_attr_group,
>> + &tad_pmu_format_attr_group,
>> + &tad_pmu_cpumask_attr_group,
>> + NULL,
>> +};
>> +
>> +static int tad_pmu_probe(struct platform_device *pdev) {
>> + struct device_node *node = pdev->dev.of_node;
>> + struct tad_region *regions;
>> + struct tad_pmu *tad_pmu;
>> + struct resource *res;
>> + u32 tad_pmu_page_size;
>> + u32 tad_page_size;
>> + u32 tad_cnt;
>> + int i, ret;
>> + char *name;
>> +
>> + tad_pmu = devm_kzalloc(&pdev->dev, sizeof(*tad_pmu),
>GFP_KERNEL);
>> + if (!tad_pmu)
>> + return -ENOMEM;
>> +
>> + platform_set_drvdata(pdev, tad_pmu);
>> +
>> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
>> + if (!res) {
>> + dev_err(&pdev->dev, "Mem resource not found\n");
>> + return -ENODEV;
>> + }
>> +
>> + ret = of_property_read_u32(node, "tad-page-size", &tad_page_size);
>> + if (ret) {
>> + dev_err(&pdev->dev, "Can't find tad-page-size property\n");
>> + return ret;
>> + }
>> +
>> + ret = of_property_read_u32(node, "tad-pmu-page-size",
>> + &tad_pmu_page_size);
>> + if (ret) {
>> + dev_err(&pdev->dev, "Can't find tad-pmu-page-size
>property\n");
>> + return ret;
>> + }
>> +
>> + ret = of_property_read_u32(node, "tad-cnt", &tad_cnt);
>> + if (ret) {
>> + dev_err(&pdev->dev, "Can't find tad-cnt property\n");
>> + return ret;
>> + }
>> +
>> + regions = devm_kcalloc(&pdev->dev, tad_cnt,
>> + sizeof(*regions), GFP_KERNEL);
>> + if (!regions)
>> + return -ENOMEM;
>> +
>> + /* ioremap the distributed TAD pmu regions */
>> + for (i = 0; i < tad_cnt && res->start < res->end; i++) {
>> + regions[i].base = devm_ioremap(&pdev->dev,
>> + res->start,
>> + tad_pmu_page_size);
>> + if (IS_ERR(regions[i].base)) {
>> + dev_err(&pdev->dev, "TAD%d ioremap fail\n", i);
>> + return -ENOMEM;
>> + }
>> + res->start += tad_page_size;
>> + }
>> +
>> + tad_pmu->regions = regions;
>> + tad_pmu->region_cnt = tad_cnt;
>> +
>> + tad_pmu->pmu = (struct pmu) {
>> +
>> + .module = THIS_MODULE,
>> + .attr_groups = tad_pmu_attr_groups,
>> + .capabilities = PERF_PMU_CAP_NO_EXCLUDE |
>> + PERF_PMU_CAP_NO_INTERRUPT,
>> + .task_ctx_nr = perf_invalid_context,
>> +
>> + .event_init = tad_pmu_event_init,
>> + .add = tad_pmu_event_counter_add,
>> + .del = tad_pmu_event_counter_del,
>> + .start = tad_pmu_event_counter_start,
>> + .stop = tad_pmu_event_counter_stop,
>> + .read = tad_pmu_event_counter_read,
>> + };
>> +
>> + tad_pmu->cpu = raw_smp_processor_id();
>> +
>
>Hi Bhaskara,
> I think there is some memory leaks in this function. Incase cpuotplug code
>fails, don't we need to free momory allocated to `tad_pmu`?
>
>Thanks,
>Kajol Jain
>
>
>> + /* Register pmu instance for cpu hotplug */
>> + ret = cpuhp_state_add_instance_nocalls(tad_pmu_cpuhp_state,
>> + &tad_pmu->node);
>> + if (ret) {
>> + dev_err(&pdev->dev, "Error %d registering hotplug\n", ret);
>> + return ret;
>> + }
>> +
>> + name = "tad";
>> + ret = perf_pmu_register(&tad_pmu->pmu, name, -1);
>> + if (ret)
>> +
> cpuhp_state_remove_instance_nocalls(tad_pmu_cpuhp_state,
>> + &tad_pmu->node);
>> +
>> + return ret;
>> +}
>> +
>> +static int tad_pmu_remove(struct platform_device *pdev) {
>> + struct tad_pmu *pmu = platform_get_drvdata(pdev);
>> +
>> + cpuhp_state_remove_instance_nocalls(tad_pmu_cpuhp_state,
>> + &pmu->node);
>> + perf_pmu_unregister(&pmu->pmu);
>> +
>> + return 0;
>> +}
>> +
>> +static const struct of_device_id tad_pmu_of_match[] = {
>> + { .compatible = "marvell,cn10k-tad-pmu", },
>> + {},
>> +};
>> +
>> +static struct platform_driver tad_pmu_driver = {
>> + .driver = {
>> + .name = "cn10k_tad_pmu",
>> + .of_match_table = of_match_ptr(tad_pmu_of_match),
>> + .suppress_bind_attrs = true,
>> + },
>> + .probe = tad_pmu_probe,
>> + .remove = tad_pmu_remove,
>> +};
>> +
>> +static int tad_pmu_offline_cpu(unsigned int cpu, struct hlist_node
>> +*node) {
>> + struct tad_pmu *pmu = hlist_entry_safe(node, struct tad_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 __init tad_pmu_init(void)
>> +{
>> + int ret;
>> +
>> + ret = cpuhp_setup_state_multi(CPUHP_AP_ONLINE_DYN,
>> + "perf/cn10k/tadpmu:online",
>> + NULL,
>> + tad_pmu_offline_cpu);
>
>> + if (ret < 0)
>> + return ret;
>> + tad_pmu_cpuhp_state = ret;
>> + return platform_driver_register(&tad_pmu_driver);
>> +}
>> +
>> +static void __exit tad_pmu_exit(void) {
>> + platform_driver_unregister(&tad_pmu_driver);
>> + cpuhp_remove_multi_state(tad_pmu_cpuhp_state);
>> +}
>> +
>> +module_init(tad_pmu_init);
>> +module_exit(tad_pmu_exit);
>> +
>> +MODULE_DESCRIPTION("Marvell CN10K LLC-TAD Perf driver");
>> +MODULE_AUTHOR("Bhaskara Budiredla <bbudiredla@xxxxxxxxxxx>");
>> +MODULE_LICENSE("GPL v2");
>>