[RFC PATCH v1 2/4] drivers/perf: hisi: Add driver support for HiSilicon PMCU
Jonathan Cameron
Jonathan.Cameron at Huawei.com
Fri Mar 17 07:52:32 PDT 2023
On Mon, 6 Feb 2023 14:51:44 +0800
Jie Zhan <zhanjie9 at hisilicon.com> wrote:
> HiSilicon Performance Monitor Control Unit (PMCU) is a device that offloads
> PMU accesses from CPUs, handling the configuration, event switching, and
> counter reading of core PMUs on Kunpeng SoC. It facilitates fine-grained
> and multi-PMU-event CPU profiling, in which scenario the current 'perf'
> scheme may lose events or drop sampling frequency. With PMCU, users can
> reliably obtain the data of up to 240 PMU events with the sample interval
> of events down to 1ms, while the software overhead of accessing PMUs, as
> well as its impact on target workloads, is reduced.
>
> This driver enables the usage of PMCU through the perf_event framework.
> PMCU is registered as a PMU device and utilises the AUX buffer to dump data
> directly. Users can start PMCU sampling through 'perf-record'. Event
> numbers are passed by a sysfs interface.
>
> Signed-off-by: Jie Zhan <zhanjie9 at hisilicon.com>
Hi Jie,
A few minor comments inline.
Whilst I looked at this internally, that was a while back so I've
found a few new things to point out in what I think is a pretty good/clean driver.
The main thing here is the RFC questions you've raised in the cover letter
of course - particularly the one around mediating who has the counters between
this and the normal PMU driver.
Thanks,
Jonathan
> ---
> drivers/perf/hisilicon/Kconfig | 15 +
> drivers/perf/hisilicon/Makefile | 1 +
> drivers/perf/hisilicon/hisi_pmcu.c | 1096 ++++++++++++++++++++++++++++
> 3 files changed, 1112 insertions(+)
> create mode 100644 drivers/perf/hisilicon/hisi_pmcu.c
>
> diff --git a/drivers/perf/hisilicon/Kconfig b/drivers/perf/hisilicon/Kconfig
> index 171bfc1b6bc2..d7728fbe8519 100644
> --- a/drivers/perf/hisilicon/Kconfig
> +++ b/drivers/perf/hisilicon/Kconfig
> @@ -24,3 +24,18 @@ config HNS3_PMU
> devices.
> Adds the HNS3 PMU into perf events system for monitoring latency,
> bandwidth etc.
> +
> +config HISI_PMCU
> + tristate "HiSilicon PMCU"
> + depends on ARM64 && PID_IN_CONTEXTIDR
> + help
> + Support for HiSilicon Performance Monitor Control Unit (PMCU).
> + HiSilicon Performance Monitor Control Unit (PMCU) is a device that
> + offloads PMU accesses from CPUs, handling the configuration, event
> + switching, and counter reading of core PMUs on Kunpeng SoC. It
> + facilitates fine-grained and multi-PMU-event CPU profiling, in which
> + scenario the current 'perf' scheme may lose events or drop sampling
> + frequency. With PMCU, users can reliably obtain the data of up to 240
> + PMU events with the sample interval of events down to 1ms, while the
> + software overhead of accessing PMUs, as well as its impact on target
> + workloads, is reduced.
> diff --git a/drivers/perf/hisilicon/Makefile b/drivers/perf/hisilicon/Makefile
> index 4d2c9abe3372..93e4e6f2816a 100644
> --- a/drivers/perf/hisilicon/Makefile
> +++ b/drivers/perf/hisilicon/Makefile
> @@ -5,3 +5,4 @@ obj-$(CONFIG_HISI_PMU) += hisi_uncore_pmu.o hisi_uncore_l3c_pmu.o \
>
> obj-$(CONFIG_HISI_PCIE_PMU) += hisi_pcie_pmu.o
> obj-$(CONFIG_HNS3_PMU) += hns3_pmu.o
> +obj-$(CONFIG_HISI_PMCU) += hisi_pmcu.o
> diff --git a/drivers/perf/hisilicon/hisi_pmcu.c b/drivers/perf/hisilicon/hisi_pmcu.c
> new file mode 100644
> index 000000000000..6ec5d6c31e1f
> --- /dev/null
> +++ b/drivers/perf/hisilicon/hisi_pmcu.c
> @@ -0,0 +1,1096 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * HiSilicon Performance Monitor Control Unit (PMCU) driver
> + *
> + * Copyright (C) 2022 HiSilicon Limited
> + * Author: Jie Zhan <zhanjie9 at hisilicon.com>
> + */
> +
> +#include <linux/acpi.h>
Not seeing this used. Probably want mod_devicetable.h that
includes the struct acpi_device_id definition.
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> +#include <linux/cpumask.h>
> +#include <linux/delay.h>
> +#include <linux/dev_printk.h>
> +#include <linux/device.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/errno.h>
> +#include <linux/gfp_types.h>
It is very very rare for this to be included directly.
Normally just rely on indirect inclusion from slab.h or similar.
I would drop this one.
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/mm_types.h>
> +#include <linux/module.h>
> +#include <linux/perf_event.h>
> +#include <linux/platform_device.h>
> +#include <linux/printk.h>
property.h
> +#include <linux/slab.h>
> +#include <linux/smp.h>
> +#include <linux/threads.h>
> +#include <linux/vmalloc.h>
> +
> +#include <asm/cputype.h>
> +#include <asm/sysreg.h>
> +
> +/* Registers */
> +#define HISI_PMCU_REG_FSM_STATUS 0x0000
> +#define HISI_PMCU_REG_FSM_CFG 0x0004
> +#define HISI_PMCU_REG_EVENT_BASE_H 0x0008
> +#define HISI_PMCU_REG_EVENT_BASE_L 0x000C
> +#define HISI_PMCU_REG_KILL_BASE_H 0x0010
> +#define HISI_PMCU_REG_KILL_BASE_L 0x0014
> +#define HISI_PMCU_REG_STORE_BASE_H 0x0018
> +#define HISI_PMCU_REG_STORE_BASE_L 0x001C
> +#define HISI_PMCU_REG_WAIT_CNT 0x0020
> +#define HISI_PMCU_REG_FSM_CTRL 0x0038
> +#define HISI_PMCU_REG_FSM_BRK 0x003C
> +#define HISI_PMCU_REG_COMP 0x0044
> +#define HISI_PMCU_REG_INT_EN 0x0100
> +#define HISI_PMCU_REG_INT_MSK 0x0104
> +#define HISI_PMCU_REG_INT_STAT 0x0108
> +#define HISI_PMCU_REG_INT_CLR 0x010C
> +#define HISI_PMCU_REG_PMCR 0x0200
> +#define HISI_PMCU_REG_PMCCFILTR 0x0204
> +
> +/* Register related configs */
> +#define HISI_PMCU_FSM_CFG_EV_LEN_MSK GENMASK(7, 0)
> +#define HISI_PMCU_FSM_CFG_NR_LOOP_MSK GENMASK(15, 8)
> +#define HISI_PMCU_FSM_CFG_NR_PMU_MSK GENMASK(19, 16)
> +#define HISI_PMCU_FSM_CFG_MAX_EV_LEN 240
As this is used in various places that are only loosely assocated
with this register, I'd just rename it HISI_PMCU_MAX_EVN_LEN.
Similar probably applies to some of these others.
> +#define HISI_PMCU_FSM_CFG_MAX_NR_LOOP 255
> +#define HISI_PMCU_FSM_CFG_MAX_NR_PMU 8
> +#define HISI_PMCU_FSM_CFG_MAX_NR_PMU_C 5
> +#define HISI_PMCU_WAIT_CNT_DEFAULT 0x249F0
> +#define HISI_PMCU_FSM_CTRL_TRIGGER BIT(0)
> +#define HISI_PMCU_FSM_BRK_BRK BIT(0)
> +#define HISI_PMCU_COMP_HPMN_THR 3
> +#define HISI_PMCU_COMP_ENABLE BIT(0)
> +#define HISI_PMCU_INT_DONE BIT(0)
> +#define HISI_PMCU_INT_BRK BIT(1)
> +#define HISI_PMCU_INT_ALL GENMASK(1, 0)
> +#define HISI_PMCU_PMCR_DEFAULT 0xC1
How is this related to the architecture defined PMCR register?
Or just a coincidence of naming?
Either way, I'm assuming 0xC1 is probably multiple fields so if
possible can we break this down further with defines to show
where the value comes from.
> +#define HISI_PMCU_PMCCFILTR_MSK GENMASK(31, 24)
...
> +/**
> + * struct hisi_pmcu_events - PMCU events and sampling configuration
> + * @nr_pmu: number of core PMU counters that run in parallel
> + * @padding: number of padding events in a sample
> + * @nr_ev: number of events passed by users in a sample
> + * @nr_ev_per_sample: number of events passed to hardware for a sample
> + * This equals nr_ev + padding and should be evenly
> + * divisible by nr_pmu.
> + * @max_sample_loop: max number of samples that can be done in a loop
> + * @ev_len: event length for hardware to read in a loop
> + * @nr_loop: number of loops in one trigger
> + * @comp_mode: compatibility mode
> + * @nr_sample: number of samples that the current trigger takes
> + * @nr_pending_sample: number of pending samples
> + * @subsample_size: size of a subsample
> + * @sample_size: size of a sample
> + * @output_size: size of output from one trigger
> + * @sample_period: sample period passed to hardware
> + * @nr_cpu: number of hardware threads (logical CPUs)
> + * @events: event IDs passed from users
Maybe say what they are for rather than where they come from?
event IDs to sample.
> + */
> +struct hisi_pmcu_events {
> + u8 nr_pmu;
> + u8 padding;
> + u8 nr_ev;
> + u8 nr_ev_per_sample;
> + u8 max_sample_loop;
> + u8 ev_len;
> + u8 nr_loop;
> + u8 comp_mode;
Could you use the enum hisi_pmcu_comp_mode type for this?
> + u32 nr_sample;
> + u32 nr_pending_sample;
> + u32 subsample_size;
> + u32 sample_size;
> + u32 output_size;
> + u32 sample_period;
> + u32 nr_cpu;
> + u32 events[HISI_PMCU_FSM_CFG_MAX_EV_LEN];
> +};
> +
...
> +static const struct attribute_group hisi_pmcu_format_attr_group = {
> + .name = "format",
> + .attrs = hisi_pmcu_format_attrs,
> +};
> +
> +static ssize_t monitored_cpus_show(struct device *dev,
> + struct device_attribute *attr, char *buf)
> +{
> + struct hisi_pmcu *hisi_pmcu = to_hisi_pmcu(dev_get_drvdata(dev));
> +
> + return sysfs_emit(buf, "%d-%d\n",
> + cpumask_first(&hisi_pmcu->cpus),
> + cpumask_last(&hisi_pmcu->cpus));
What does this do about offline CPUs?
Should it include them or not?
> +}
> +
> +static DEVICE_ATTR_ADMIN_RO(monitored_cpus);
> +static ssize_t user_events_store(struct device *dev,
> + struct device_attribute *attr,
> + const char *buf, size_t count)
> +{
> + struct hisi_pmcu *hisi_pmcu = to_hisi_pmcu(dev_get_drvdata(dev));
> + struct hisi_pmcu_user_events *user_ev = &hisi_pmcu->user_ev;
> + u32 head, tail, nr_ev;
> + char *line;
> + int err;
> +
> + line = kcalloc(count + 1, sizeof(*line), GFP_KERNEL);
Doesn't seem to be freed anywhere.
> + nr_ev = 0;
> + head = 0;
> + tail = 0;
> + while (nr_ev < HISI_PMCU_FSM_CFG_MAX_EV_LEN) {
> + while (head < count && isspace(buf[head]))
> + head++;
> + if (!isxdigit(buf[head]))
> + break;
> + tail = head + 1;
> +
> + while (tail < count && isalnum(buf[tail]))
> + tail++;
> +
> + strncpy(line, buf + head, tail - head);
> + line[tail - head] = '\0';
> + err = kstrtou16(line, 16, &user_ev->ev[nr_ev]);
> + if (err) {
> + user_ev->nr_ev = 0;
> + return err;
> + }
> + nr_ev++;
> + head = tail;
> + }
> + user_ev->nr_ev = nr_ev;
> +
> + return count;
> +}
> +
> +static int hisi_pmcu_pmu_event_init(struct perf_event *event)
> +{
> + struct hisi_pmcu *hisi_pmcu = to_hisi_pmcu(event->pmu);
> + struct hisi_pmcu_events *ev = &hisi_pmcu->ev;
> + void __iomem *base = hisi_pmcu->regbase;
> + u64 cfg;
> + u32 val;
> +
> + if (event->attr.type != hisi_pmcu->pmu.type)
> + return -ENOENT;
> +
> + if (hisi_pmcu->busy)
> + return -EBUSY;
> +
> + cfg = event->attr.config;
> +
> + val = FIELD_GET(HISI_PMCU_PERF_ATTR_NR_SAMPLE, cfg);
val gets used for a lot of different things in this function.
I would use as set of new local variables with names that make it more
obvious what they are.
> + ev->nr_pending_sample = val ? val : HISI_PMCU_PERF_NR_SAMPLE_DEFAULT;
local variable isn't that useful here and makes the whole reuse of value
issue worse.
ev->nr_pending_sample = FIELD_GET(...);
if (ev->nr_pending_sample == 0)
ev->nr_pending_sample = HISI...
> +
> + val = FIELD_GET(HISI_PMCU_PERF_ATTR_SAMPLE_PERIOD_MS, cfg);
> + if (val > HISI_PMCU_PERF_MAX_SAMPLE_PERIOD_MS) {
> + dev_err(hisi_pmcu->dev, "sample period too long (max=0x%x)\n",
> + HISI_PMCU_PERF_MAX_SAMPLE_PERIOD_MS);
> + return -EINVAL;
> + }
> + ev->sample_period = val ? val * HISI_PMCU_PERF_MS_TO_WAIT_CNT :
> + HISI_PMCU_WAIT_CNT_DEFAULT;
> +
> + cfg = event->attr.config1;
> +
> + val = FIELD_GET(HISI_PMCU_PERF_ATTR_PMCCFILTR, cfg);
> + val = FIELD_PREP(HISI_PMCU_PMCCFILTR_MSK, val);
> + writel(val, base + HISI_PMCU_REG_PMCCFILTR);
> +
> + return 0;
> +}
> +
...
> +static void hisi_pmcu_hw_sample_start(struct hisi_pmcu *hisi_pmcu,
> + struct hisi_pmcu_buf *buf)
> +{
> + struct hisi_pmcu_sbuf *sbuf = &buf->sbuf[buf->cur_buf];
> + struct hisi_pmcu_events *ev = &hisi_pmcu->ev;
> + void __iomem *base = hisi_pmcu->regbase;
> + u64 addr, end;
> + u32 val;
> +
> + /* FSM CFG */
> + val = FIELD_PREP(HISI_PMCU_FSM_CFG_EV_LEN_MSK, ev->ev_len);
> + val |= FIELD_PREP(HISI_PMCU_FSM_CFG_NR_LOOP_MSK, ev->nr_loop);
> + val |= FIELD_PREP(HISI_PMCU_FSM_CFG_NR_PMU_MSK, ev->nr_pmu);
> + writel(val, base + HISI_PMCU_REG_FSM_CFG);
> +
> + /* Sample period */
> + writel(ev->sample_period, base + HISI_PMCU_REG_WAIT_CNT);
> +
> + /* Event ID base */
> + addr = virt_to_phys(ev->events);
> + val = upper_32_bits(addr);
> + writel(val, base + HISI_PMCU_REG_EVENT_BASE_H);
No point in using the local variable val here that I can see.
writel(upper_32_bits(addr), base + ...)
> + val = lower_32_bits(addr);
> + writel(val, base + HISI_PMCU_REG_EVENT_BASE_L);
same with this one.
> +
> + /* sbuf end */
> + end = page_to_phys(sbuf->page) + sbuf->size;
> +
> + /* Data output address */
> + addr = end - sbuf->remain;
> + val = upper_32_bits(addr);
> + writel(val, base + HISI_PMCU_REG_STORE_BASE_H);
and this one.
> + val = lower_32_bits(addr);
> + writel(val, base + HISI_PMCU_REG_STORE_BASE_L);
and another. etc..
> +
> + /* Stop data output if sbuf end is reached (abnormally) */
> + addr = end;
> + val = upper_32_bits(addr);
> + writel(val, base + HISI_PMCU_REG_KILL_BASE_H);
> + val = lower_32_bits(addr);
> + writel(val, base + HISI_PMCU_REG_KILL_BASE_L);
> +
> + /* Trigger */
> + writel(HISI_PMCU_FSM_CTRL_TRIGGER, base + HISI_PMCU_REG_FSM_CTRL);
> +}
> +
> +
> +static void hisi_pmcu_write_auxtrace_header(struct hisi_pmcu_events *ev,
> + struct hisi_pmcu_buf *buf)
> +{
> + struct hisi_pmcu_auxtrace_header header;
> + struct hisi_pmcu_sbuf *sbuf;
> + u32 *data;
> + u32 sz;
> +
> + sbuf = &buf->sbuf[buf->cur_buf];
> +
> + header.buffer_size = sbuf->size;
> + header.nr_pmu = ev->nr_pmu;
> + header.nr_cpu = ev->nr_cpu;
> + header.comp_mode = ev->comp_mode;
> + header.subsample_size = ev->subsample_size;
> + header.nr_subsample_per_sample = ev->nr_ev_per_sample / ev->nr_pmu;
> + header.nr_event = ev->nr_ev_per_sample;
Might be nicer to read as as
struct hisi_pmcu_sbuf *sbuf = &buf->sbuf[buf->cur_buf];
struct hisi_pmcu_auxtrace_header header = {
.buffer_size = sbuf->size,
.nr_pmu = ev->nr_pmu,
.nr_cpu = ev->nr_cpu,
...
};
> +
> + data = page_to_virt(sbuf->page);
> + memcpy(data, &header, sizeof(header));
> + memcpy(data + sizeof(header) / sizeof(*data), ev->events,
> + ev->nr_ev_per_sample * sizeof(u32));
I'm not sure why data is a u32 *
A few things that would make this neater.
* write the header directly.
struct hisi_pmcu_auxtrace_header *header = page_to_virt(sbuf->page);
*header = (struct hisi_pmcu_auxtrace_header) {
.buffer_size = sbuf->size,
.nr_pmu = ev->nr_pmu,
.nr_cpu = ev->nr_cpu,
...
};
* Use header + 1 to get to the address just after it.
memcpy(header + 1, ev->events, ev->nr_ev_per_sample * sizeof(u32));
* Instead add teh data to the structure (maybe rename it)
struct hisi_pmcu_auxtrace_header {
u32 buffer_size;
u32 nr_pmu;
u32 nr_cpu;
u32 comp_mode;
u32 subsample_size;
u32 nr_subsample_per_sample;
u32 nr_event;
u32 data[];
};
> +
> + sz = sizeof(header) + ev->nr_ev_per_sample * sizeof(u32);
with above augmented header structure, struct_size()
> + sz = round_up(sz, HISI_PMCU_AUX_HEADER_ALIGN);
> +
> + sbuf->remain -= sz;
> +}
> +
> +static void hisi_pmcu_pmu_start(struct perf_event *event, int flags)
> +{
> + struct hisi_pmcu *hisi_pmcu = to_hisi_pmcu(event->pmu);
> + struct perf_output_handle *handle = &hisi_pmcu->handle;
> + struct hw_perf_event *hwc = &event->hw;
> + struct hisi_pmcu_buf *buf;
> + int err;
> +
> + spin_lock(&hisi_pmcu->lock);
> +
> + if (hisi_pmcu->busy) {
> + dev_info(hisi_pmcu->dev,
> + "Sampling is running, pmu->start() ignored\n");
I'm not sure on perf convention on this, but I'd have though dev_dbg
enough for this. If this is normal thing to do then feel free to leave it.
> + goto out;
> + }
> +
...
> +
> +static void hisi_pmcu_pmu_stop(struct perf_event *event, int flags)
> +{
> + struct hisi_pmcu *hisi_pmcu = to_hisi_pmcu(event->pmu);
> + struct hw_perf_event *hwc = &event->hw;
> + struct perf_output_handle *handle;
> + struct hisi_pmcu_sbuf *sbuf;
> + struct hisi_pmcu_buf *buf;
> + int err;
> +
> + spin_lock(&hisi_pmcu->lock);
> +
> + handle = &hisi_pmcu->handle;
> +
> + /* If PMCU is running, break it */
> + if (hisi_pmcu->busy) {
> + dev_info(hisi_pmcu->dev, "Stopping PMCU sampling\n");
Is this useful? dev_dbg maybe?
> + err = hisi_pmcu_hw_sample_stop(hisi_pmcu);
> + if (err)
> + dev_err(hisi_pmcu->dev,
> + "Timed out for stopping PMCU!\n");
> + }
> +
> + buf = perf_get_aux(handle);
> + sbuf = &buf->sbuf[buf->cur_buf];
> + perf_aux_output_end(handle, sbuf->size - sbuf->remain);
> +
> + spin_unlock(&hisi_pmcu->lock);
> +
> + hwc->state |= PERF_HES_STOPPED;
> + perf_event_update_userpage(event);
> +}
...
> +static int hisi_pmcu_init_data(struct platform_device *pdev,
> + struct hisi_pmcu *hisi_pmcu)
> +{
> + int ret;
> +
> + hisi_pmcu->regbase = devm_platform_ioremap_resource(pdev, 0);
> + if (IS_ERR(hisi_pmcu->regbase))
> + return dev_err_probe(&pdev->dev, -ENODEV,
> + "Failed to map device register space\n");
> +
> + ret = device_property_read_u32(&pdev->dev, "hisilicon,scl-id",
> + &hisi_pmcu->scclid);
These need linux/property.h to be included (mentioned above)
> + if (ret < 0)
> + return dev_err_probe(&pdev->dev, ret,
> + "Failed to read sccl-id!\n");
> +
> + /*
> + * Obtain the number of CPUs that contributes to the sample size.
> + * NR_CPU_CLUSTER is now hard coded as the hardware accesses a certain
> + * number of CPUs in a cluster regardless of how many CPUs are actually
> + * implemented/available.
> + */
> + ret = device_property_read_u32(&pdev->dev, "hisilicon,nr-cluster",
> + &hisi_pmcu->ev.nr_cpu);
> + if (ret < 0)
> + return dev_err_probe(&pdev->dev, ret,
> + "Failed to read nr-cluster!\n");
> + hisi_pmcu->ev.nr_cpu *= NR_CPU_CLUSTER;
> +
> + return 0;
> +}
> +static struct platform_driver hisi_pmcu_driver = {
> + .driver = {
> + .name = HISI_PMCU_DRV_NAME,
> + .acpi_match_table = hisi_pmcu_acpi_match,
> + /*
> + * Unbinding driver is not yet supported as we have not worked
> + * out a safe bind/unbind process.
I'd add a note on this to the cover letter and the above
patch description. It's definitely something we should
make work for this driver.
> + */
> + .suppress_bind_attrs = true,
> + },
> + .probe = hisi_pmcu_probe,
> +};
> +
..
I'm very interested to see what this hardware/driver gets used for.
Thanks,
Jonathan
More information about the linux-arm-kernel
mailing list