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Message-ID: <CAHrpEqTtCnEU1v1sEuN8yJGPudDRZ5A79=Wn5Bp4SgTxDiNTQQ@mail.gmail.com>
Date: Mon, 29 Aug 2016 11:06:44 -0500
From: Zhi Li <lznuaa@...il.com>
To: Zhengyu Shen <zhengyu.shen@....com>
Cc: Shawn Guo <shawnguo@...nel.org>, Frank Li <frank.li@....com>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
kernel list <linux-kernel@...r.kernel.org>,
peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
alexander.shishkin@...ux.intel.com,
Mark Rutland <mark.rutland@....com>
Subject: Re: [PATCH v3] Added perf functionality to mmdc driver
On Wed, Aug 17, 2016 at 2:42 PM, Zhengyu Shen <zhengyu.shen@....com> wrote:
> MMDC is a multi-mode DDR controller that supports DDR3/DDR3L x16/x32/x64
> and LPDDR2 two channel x16/x32 memory types. MMDC is configurable, high
> performance, and optimized. MMDC is present on i.MX6 Quad and i.MX6
> QuadPlus devices, but this driver only supports i.MX6 Quad at the moment.
> MMDC provides registers for performance counters which read via this
> driver to help debug memory throughput and similar issues.
>
> $ perf stat -a -e mmdc/busy-cycles/,mmdc/read-accesses/,mmdc/read-bytes/,mmdc/total-cycles/,mmdc/write-accesses/,mmdc/write-bytes/ dd if=/dev/zero of=/dev/null bs=1M count=5000
> Performance counter stats for 'dd if=/dev/zero of=/dev/null bs=1M count=5000':
>
> 898021787 mmdc/busy-cycles/
> 14819600 mmdc/read-accesses/
> 471.30 MB mmdc/read-bytes/
> 2815419216 mmdc/total-cycles/
> 13367354 mmdc/write-accesses/
> 427.76 MB mmdc/write-bytes/
>
> 5.334757334 seconds time elapsed
>
> Signed-off-by: Zhengyu Shen <zhengyu.shen@....com>
> Signed-off-by: Frank Li <frank.li@....com>
Shawn Guo:
No new comments got more than 1 weeks.
Did you plan accept it?
best regards
Frank Li
> ---
> Changes from v2 to v3:
> Use WARN_ONCE instead of returning generic error values
> Replace CPU Notifiers with newer state machine hotplug
> Added additional checks on event_init for grouping and sampling
> Remove useless mmdc_enable_profiling function
> Added comments
> Moved start index of events from 0x01 to 0x00
> Added a counter to pmu_mmdc to only stop hrtimer after all events are finished
> Replace readl_relaxed and writel_relaxed with readl and writel
> Removed duplicate update function
> Used devm_kasprintf when naming mmdcs probed
>
> Changes from v1 to v2:
> Added cpumask and migration handling support to driver
> Validated event during event_init
> Added code to properly stop counters
> Used perf_invalid_context instead of perf_sw_context
> Added hrtimer to poll for overflow
> Added better description
> Added support for multiple mmdcs
>
> arch/arm/mach-imx/mmdc.c | 384 ++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 383 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/mach-imx/mmdc.c b/arch/arm/mach-imx/mmdc.c
> index db9621c..5fe7696 100644
> --- a/arch/arm/mach-imx/mmdc.c
> +++ b/arch/arm/mach-imx/mmdc.c
> @@ -1,5 +1,5 @@
> /*
> - * Copyright 2011 Freescale Semiconductor, Inc.
> + * Copyright 2011,2016 Freescale Semiconductor, Inc.
> * Copyright 2011 Linaro Ltd.
> *
> * The code contained herein is licensed under the GNU General Public
> @@ -16,6 +16,11 @@
> #include <linux/of.h>
> #include <linux/of_address.h>
> #include <linux/of_device.h>
> +#include <linux/perf_event.h>
> +#include <linux/slab.h>
> +#include <linux/hrtimer.h>
> +#include <linux/interrupt.h>
> +#include <linux/spinlock.h>
>
> #include "common.h"
>
> @@ -27,14 +32,363 @@
> #define BM_MMDC_MDMISC_DDR_TYPE 0x18
> #define BP_MMDC_MDMISC_DDR_TYPE 0x3
>
> +#define TOTAL_CYCLES 0x0
> +#define BUSY_CYCLES 0x1
> +#define READ_ACCESSES 0x2
> +#define WRITE_ACCESSES 0x3
> +#define READ_BYTES 0x4
> +#define WRITE_BYTES 0x5
> +
> +/* Enables, resets, freezes, overflow profiling*/
> +#define DBG_DIS 0x0
> +#define DBG_EN 0x1
> +#define DBG_RST 0x2
> +#define PRF_FRZ 0x4
> +#define CYC_OVF 0x8
> +
> +#define MMDC_MADPCR0 0x410
> +#define MMDC_MADPSR0 0x418
> +#define MMDC_MADPSR1 0x41C
> +#define MMDC_MADPSR2 0x420
> +#define MMDC_MADPSR3 0x424
> +#define MMDC_MADPSR4 0x428
> +#define MMDC_MADPSR5 0x42C
> +
> +#define MMDC_NUM_COUNTERS 6
> +
> +#define to_mmdc_pmu(p) (container_of(p, struct mmdc_pmu, pmu))
> +
> +static DEFINE_IDA(mmdc_ida);
> +
> static int ddr_type;
>
> +PMU_EVENT_ATTR_STRING(total-cycles, mmdc_total_cycles, "event=0x00")
> +PMU_EVENT_ATTR_STRING(busy-cycles, mmdc_busy_cycles, "event=0x01")
> +PMU_EVENT_ATTR_STRING(read-accesses, mmdc_read_accesses, "event=0x02")
> +PMU_EVENT_ATTR_STRING(write-accesses, mmdc_write_accesses, "config=0x03")
> +PMU_EVENT_ATTR_STRING(read-bytes, mmdc_read_bytes, "event=0x04")
> +PMU_EVENT_ATTR_STRING(read-bytes.unit, mmdc_read_bytes_unit, "MB");
> +PMU_EVENT_ATTR_STRING(read-bytes.scale, mmdc_read_bytes_scale, "0.000001");
> +PMU_EVENT_ATTR_STRING(write-bytes, mmdc_write_bytes, "event=0x05")
> +PMU_EVENT_ATTR_STRING(write-bytes.unit, mmdc_write_bytes_unit, "MB");
> +PMU_EVENT_ATTR_STRING(write-bytes.scale, mmdc_write_bytes_scale, "0.000001");
> +
> +struct mmdc_pmu {
> + struct pmu pmu;
> + void __iomem *mmdc_base;
> + cpumask_t cpu;
> + struct hrtimer hrtimer;
> + unsigned int irq;
> + unsigned int active_events;
> + struct device *dev;
> + struct perf_event *mmdc_events[MMDC_NUM_COUNTERS];
> + spinlock_t mmdc_active_events_lock;
> +};
> +static struct mmdc_pmu *cpuhp_mmdc_pmu;
> +
> +/* polling period is set to one second, overflow of total-cycles (the fastest
> + * increasing counter) takes ten seconds so one second is safe
> + */
> +static unsigned int mmdc_poll_period_us = 1000000;
> +module_param_named(pmu_poll_period_us, mmdc_poll_period_us, uint,
> + S_IRUGO | S_IWUSR);
> +
> +static ktime_t mmdc_timer_period(void)
> +{
> + return ns_to_ktime((u64)mmdc_poll_period_us * 1000);
> +}
> +
> +static ssize_t mmdc_cpumask_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct mmdc_pmu *pmu_mmdc = dev_get_drvdata(dev);
> +
> + return cpumap_print_to_pagebuf(true, buf, &pmu_mmdc->cpu);
> +}
> +
> +static struct device_attribute mmdc_cpumask_attr =
> +__ATTR(cpumask, S_IRUGO, mmdc_cpumask_show, NULL);
> +
> +static struct attribute *mmdc_cpumask_attrs[] = {
> + &mmdc_cpumask_attr.attr,
> + NULL,
> +};
> +
> +static struct attribute_group mmdc_cpumask_attr_group = {
> + .attrs = mmdc_cpumask_attrs,
> +};
> +
> +static struct attribute *mmdc_events_attrs[] = {
> + &mmdc_total_cycles.attr.attr,
> + &mmdc_busy_cycles.attr.attr,
> + &mmdc_read_accesses.attr.attr,
> + &mmdc_write_accesses.attr.attr,
> + &mmdc_read_bytes.attr.attr,
> + &mmdc_read_bytes_unit.attr.attr,
> + &mmdc_read_bytes_scale.attr.attr,
> + &mmdc_write_bytes.attr.attr,
> + &mmdc_write_bytes_unit.attr.attr,
> + &mmdc_write_bytes_scale.attr.attr,
> + NULL,
> +};
> +
> +static struct attribute_group mmdc_events_attr_group = {
> + .name = "events",
> + .attrs = mmdc_events_attrs,
> +};
> +
> +PMU_FORMAT_ATTR(event, "config:0-63");
> +static struct attribute *mmdc_format_attrs[] = {
> + &format_attr_event.attr,
> + NULL,
> +};
> +
> +static struct attribute_group mmdc_format_attr_group = {
> + .name = "format",
> + .attrs = mmdc_format_attrs,
> +};
> +
> +static const struct attribute_group *attr_groups[] = {
> + &mmdc_events_attr_group,
> + &mmdc_format_attr_group,
> + &mmdc_cpumask_attr_group,
> + NULL,
> +};
> +
> +static u32 mmdc_read_counter(struct mmdc_pmu *pmu_mmdc, int cfg, u64 prev_val)
> +{
> + u32 val;
> + void __iomem *mmdc_base, *reg;
> +
> + mmdc_base = pmu_mmdc->mmdc_base;
> +
> + switch (cfg) {
> + case TOTAL_CYCLES:
> + reg = mmdc_base + MMDC_MADPSR0;
> + break;
> + case BUSY_CYCLES:
> + reg = mmdc_base + MMDC_MADPSR1;
> + break;
> + case READ_ACCESSES:
> + reg = mmdc_base + MMDC_MADPSR2;
> + break;
> + case WRITE_ACCESSES:
> + reg = mmdc_base + MMDC_MADPSR3;
> + break;
> + case READ_BYTES:
> + reg = mmdc_base + MMDC_MADPSR4;
> + break;
> + case WRITE_BYTES:
> + reg = mmdc_base + MMDC_MADPSR5;
> + break;
> + default:
> + return WARN_ONCE(1,
> + "invalid configuration %d for mmdc counter", cfg);
> + }
> + val = readl(reg);
> + return val;
> +}
> +
> +static int mmdc_pmu_offline_cpu(unsigned int cpu)
> +{
> + struct mmdc_pmu *pmu_mmdc = cpuhp_mmdc_pmu;
> + int target;
> +
> + if (!cpumask_test_and_clear_cpu(cpu, &pmu_mmdc->cpu))
> + return 0;
> + target = cpumask_any_but(cpu_online_mask, cpu);
> + if (target >= nr_cpu_ids)
> + return 0;
> + perf_pmu_migrate_context(&pmu_mmdc->pmu, cpu, target);
> + cpumask_set_cpu(target, &pmu_mmdc->cpu);
> + if (pmu_mmdc->irq)
> + WARN_ON(irq_set_affinity_hint(
> + pmu_mmdc->irq, &pmu_mmdc->cpu) != 0);
> + return 0;
> +}
> +
> +static int mmdc_event_init(struct perf_event *event)
> +{
> + struct mmdc_pmu *pmu_mmdc = to_mmdc_pmu(event->pmu);
> + int cfg = event->attr.config;
> + struct perf_event *sibling;
> +
> + if (event->attr.type != event->pmu->type)
> + return -ENOENT;
> +
> + if (event->cpu < 0) {
> + dev_warn(pmu_mmdc->dev, "Can't provide per-task data!\n");
> + return -EOPNOTSUPP;
> + }
> +
> + if (event->attr.exclude_user ||
> + event->attr.exclude_kernel ||
> + event->attr.exclude_hv ||
> + event->attr.exclude_idle ||
> + event->attr.exclude_host ||
> + event->attr.exclude_guest ||
> + event->attr.sample_period)
> + return -EINVAL;
> +
> + if (cfg < 0 || cfg >= MMDC_NUM_COUNTERS)
> + return -EINVAL;
> +
> + if (event->group_leader->pmu != event->pmu &&
> + !is_software_event(event->group_leader))
> + return -EINVAL;
> +
> + list_for_each_entry(sibling, &event->group_leader->sibling_list,
> + group_entry)
> + if (sibling->pmu != event->pmu &&
> + !is_software_event(sibling))
> + return -EINVAL;
> +
> + event->cpu = cpumask_first(&pmu_mmdc->cpu);
> + return 0;
> +}
> +
> +static void mmdc_event_update(struct perf_event *event)
> +{
> + struct mmdc_pmu *pmu_mmdc = to_mmdc_pmu(event->pmu);
> + u32 val;
> + u64 prev_val;
> +
> + prev_val = local64_read(&event->count);
> + val = mmdc_read_counter(pmu_mmdc, (int) event->attr.config, prev_val);
> + local64_add(val - (u32)(prev_val & 0xFFFFFFFF), &event->count);
> +}
> +
> +static void mmdc_event_start(struct perf_event *event, int flags)
> +{
> + struct mmdc_pmu *pmu_mmdc = to_mmdc_pmu(event->pmu);
> + void __iomem *mmdc_base, *reg;
> +
> + mmdc_base = pmu_mmdc->mmdc_base;
> + reg = mmdc_base + MMDC_MADPCR0;
> + /* hrtimer is required because mmdc does not provide an interrupt so
> + * polling is necessary
> + */
> + hrtimer_start(&pmu_mmdc->hrtimer, mmdc_timer_period(),
> + HRTIMER_MODE_REL_PINNED);
> +
> + writel(DBG_RST, reg);
> + writel(DBG_EN, reg);
> +}
> +
> +static int mmdc_event_add(struct perf_event *event, int flags)
> +{
> + struct mmdc_pmu *pmu_mmdc = to_mmdc_pmu(event->pmu);
> + int cfg = (int)event->attr.config;
> +
> + if (WARN_ONCE((cfg < 0 || cfg >= MMDC_NUM_COUNTERS),
> + "invalid configuration %d for mmdc", cfg))
> + return -1;
> + pmu_mmdc->mmdc_events[cfg] = event;
> + local64_set(&event->count, 0);
> + if (flags & PERF_EF_START)
> + mmdc_event_start(event, flags);
> + spin_lock(&pmu_mmdc->mmdc_active_events_lock);
> + pmu_mmdc->active_events++;
> + spin_unlock(&pmu_mmdc->mmdc_active_events_lock);
> + return 0;
> +}
> +
> +static void mmdc_event_stop(struct perf_event *event, int flags)
> +{
> + struct mmdc_pmu *pmu_mmdc = to_mmdc_pmu(event->pmu);
> + void __iomem *mmdc_base, *reg;
> + int cfg = (int)event->attr.config;
> +
> + mmdc_base = pmu_mmdc->mmdc_base;
> + reg = mmdc_base + MMDC_MADPCR0;
> + if (WARN_ONCE((cfg < 0 || cfg >= MMDC_NUM_COUNTERS),
> + "invalid configuration %d for mmdc counter", cfg))
> + return;
> + spin_lock(&pmu_mmdc->mmdc_active_events_lock);
> + if (pmu_mmdc->active_events <= 0)
> + hrtimer_cancel(&pmu_mmdc->hrtimer);
> + spin_unlock(&pmu_mmdc->mmdc_active_events_lock);
> + writel(PRF_FRZ, reg);
> + mmdc_event_update(event);
> +}
> +
> +static void mmdc_event_del(struct perf_event *event, int flags)
> +{
> + struct mmdc_pmu *pmu_mmdc = to_mmdc_pmu(event->pmu);
> +
> + spin_lock(&pmu_mmdc->mmdc_active_events_lock);
> + pmu_mmdc->active_events--;
> + spin_unlock(&pmu_mmdc->mmdc_active_events_lock);
> + mmdc_event_stop(event, PERF_EF_UPDATE);
> +}
> +
> +static void mmdc_overflow_handler(struct mmdc_pmu *pmu_mmdc)
> +{
> + int i;
> +
> + for (i = 0; i < MMDC_NUM_COUNTERS; i++) {
> + struct perf_event *event = pmu_mmdc->mmdc_events[i];
> +
> + if (event)
> + mmdc_event_update(event);
> + }
> +}
> +
> +static enum hrtimer_restart mmdc_timer_handler(struct hrtimer *hrtimer)
> +{
> + struct mmdc_pmu *pmu_mmdc = container_of(hrtimer, struct mmdc_pmu,
> + hrtimer);
> +
> + mmdc_overflow_handler(pmu_mmdc);
> +
> + hrtimer_forward_now(hrtimer, mmdc_timer_period());
> + return HRTIMER_RESTART;
> +}
> +
> +static int mmdc_pmu_init(struct mmdc_pmu *pmu_mmdc,
> + void __iomem *mmdc_base, struct device *dev)
> +{
> + int mmdc_num;
> +
> + *pmu_mmdc = (struct mmdc_pmu) {
> + .pmu = (struct pmu) {
> + .task_ctx_nr = perf_invalid_context,
> + .attr_groups = attr_groups,
> + .event_init = mmdc_event_init,
> + .add = mmdc_event_add,
> + .del = mmdc_event_del,
> + .start = mmdc_event_start,
> + .stop = mmdc_event_stop,
> + .read = mmdc_event_update,
> + },
> + .mmdc_base = mmdc_base,
> + };
> +
> + mmdc_num = ida_simple_get(&mmdc_ida, 0, 0, GFP_KERNEL);
> +
> + cpumask_set_cpu(smp_processor_id(), &pmu_mmdc->cpu);
> +
> + pmu_mmdc->dev = dev;
> + pmu_mmdc->active_events = 0;
> + spin_lock_init(&pmu_mmdc->mmdc_active_events_lock);
> +
> + cpuhp_mmdc_pmu = pmu_mmdc;
> + cpuhp_setup_state(CPUHP_ONLINE,
> + "PERF_MMDC_ONLINE", NULL,
> + mmdc_pmu_offline_cpu);
> +
> + return mmdc_num;
> +}
> +
> static int imx_mmdc_probe(struct platform_device *pdev)
> {
> struct device_node *np = pdev->dev.of_node;
> void __iomem *mmdc_base, *reg;
> + struct mmdc_pmu *pmu_mmdc;
> + char *name;
> u32 val;
> int timeout = 0x400;
> + int mmdc_num;
>
> mmdc_base = of_iomap(np, 0);
> WARN_ON(!mmdc_base);
> @@ -61,7 +415,34 @@ static int imx_mmdc_probe(struct platform_device *pdev)
> __func__);
> return -EBUSY;
> }
> + pmu_mmdc = kzalloc(sizeof(*pmu_mmdc), GFP_KERNEL);
> +
> + if (!pmu_mmdc) {
> + pr_err("failed to allocate PMU device!\n");
> + return -ENOMEM;
> + }
> + mmdc_num = mmdc_pmu_init(pmu_mmdc, mmdc_base, &pdev->dev);
> + hrtimer_init(&pmu_mmdc->hrtimer, CLOCK_MONOTONIC,
> + HRTIMER_MODE_REL);
> + pmu_mmdc->hrtimer.function = mmdc_timer_handler;
> + if (mmdc_num == 0)
> + name = "mmdc";
> + else
> + name = devm_kasprintf(&pdev->dev,
> + GFP_KERNEL, "mmdc_%d", mmdc_num);
> + platform_set_drvdata(pdev, pmu_mmdc);
> + perf_pmu_register(&(pmu_mmdc->pmu), name, -1);
> + return 0;
> +}
> +
> +static int imx_mmdc_remove(struct platform_device *pdev)
> +{
> + struct mmdc_pmu *pmu_mmdc = platform_get_drvdata(pdev);
>
> + perf_pmu_unregister(&pmu_mmdc->pmu);
> + cpuhp_remove_state_nocalls(CPUHP_ONLINE);
> + cpuhp_mmdc_pmu = NULL;
> + kfree(pmu_mmdc);
> return 0;
> }
>
> @@ -81,6 +462,7 @@ static struct platform_driver imx_mmdc_driver = {
> .of_match_table = imx_mmdc_dt_ids,
> },
> .probe = imx_mmdc_probe,
> + .remove = imx_mmdc_remove,
> };
>
> static int __init imx_mmdc_init(void)
> --
> 2.9.3
>
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