[Intel-xe] [PATCH v5 3/3] drm/xe/pmu: Enable PMU interface
Aravind Iddamsetty
aravind.iddamsetty at linux.intel.com
Thu Aug 31 23:11:31 UTC 2023
On 01/09/23 03:51, Belgaumkar, Vinay wrote:
>
> On 8/31/2023 3:11 PM, Aravind Iddamsetty wrote:
>> On 31/08/23 22:28, Dixit, Ashutosh wrote:
>> HI Ashutosh,
>>
>>> On Thu, 31 Aug 2023 03:29:11 -0700, Aravind Iddamsetty wrote:
>>> Hi Aravind,
>>>
>>> Hmm, what happened to the email formatting here?
>> not sure, some how my email client is showing proper or I messed up.
>>>> On Tue, 29 Aug 2023 22:15:44 -0700, Aravind Iddamsetty wrote:
>>>>
>>>> diff --git a/drivers/gpu/drm/xe/xe_pmu.c b/drivers/gpu/drm/xe/xe_pmu.c
>>>> new file mode 100644
>>>> index 000000000000..41dd422812ff
>>>> --- /dev/null
>>>> +++ b/drivers/gpu/drm/xe/xe_pmu.c
>>>> @@ -0,0 +1,679 @@
>>>> +// SPDX-License-Identifier: MIT
>>>> +/*
>>>> + * Copyright © 2023 Intel Corporation
>>>> + */
>>>> +
>>>> +#include <drm/drm_drv.h>
>>>> +#include <drm/drm_managed.h>
>>>> +#include <drm/xe_drm.h>
>>>> +
>>>> +#include "regs/xe_gt_regs.h"
>>>> +#include "xe_device.h"
>>>> +#include "xe_gt_clock.h"
>>>> +#include "xe_mmio.h"
>>>> +
>>>> +static cpumask_t xe_pmu_cpumask;
>>>> +static unsigned int xe_pmu_target_cpu = -1;
>>>> +
>>>> +static unsigned int config_gt_id(const u64 config)
>>>> +{
>>>> + return config >> __XE_PMU_GT_SHIFT;
>>>> +}
>>>> +
>>>> +static u64 config_counter(const u64 config)
>>>> +{
>>>> + return config & ~(~0ULL << __XE_PMU_GT_SHIFT);
>>>> +}
>>>> +
>>>> +static int engine_busyness_sample_type(u64 config)
>>>> +{
>>>> + int type = 0;
>>>>
>>>>
>>>> Why initialize? The switch statement should have a default with a BUG/WARN_ON
>>>> below? Also see the comment below.
>>>>
>>>> +
>>>> + switch (config) {
>>>> + case XE_PMU_RENDER_GROUP_BUSY(0):
>>>> + type = __XE_SAMPLE_RENDER_GROUP_BUSY;
>>>> + break;
>>>> + case XE_PMU_COPY_GROUP_BUSY(0):
>>>> + type = __XE_SAMPLE_COPY_GROUP_BUSY;
>>>> + break;
>>>> + case XE_PMU_MEDIA_GROUP_BUSY(0):
>>>> + type = __XE_SAMPLE_MEDIA_GROUP_BUSY;
>>>> + break;
>>>> + case XE_PMU_ANY_ENGINE_GROUP_BUSY(0):
>>>> + type = __XE_SAMPLE_ANY_ENGINE_GROUP_BUSY;
>>>> + break;
>>>> + }
>>>> +
>>>> + return type;
>>>> +}
>>>>
>>>>
>>>> I am thinking this function is not really needed. We can just do:
>>>>
>>>> int sample_type = config - 1;
>>>>
>>>> or
>>>>
>>>> int sample_type = config_counter(config) - 1;
>>>>
>>>> It might not always be true in future, the configs can start from any range.
>>> Disagree. This is uapi. Once it is exposed it cannot change. I am talking
>>> about this:
>>>
>>> +#define XE_PMU_INTERRUPTS(gt) ___XE_PMU_OTHER(gt, 0)
>>> +#define XE_PMU_RENDER_GROUP_BUSY(gt) ___XE_PMU_OTHER(gt, 1)
>>> +#define XE_PMU_COPY_GROUP_BUSY(gt) ___XE_PMU_OTHER(gt, 2)
>>> +#define XE_PMU_MEDIA_GROUP_BUSY(gt) ___XE_PMU_OTHER(gt, 3)
>>> +#define XE_PMU_ANY_ENGINE_GROUP_BUSY(gt) ___XE_PMU_OTHER(gt, 4)
>>>
>>> How can this "start from any range"? We can only add new counters after
>>> these, not before these, correct?
>> I didn't mean to say that these particular one's would change but any
>> future new events that might fall into these categories might start
>> from a different range. sorry for the confusion.
>>
>> Your suggestion makes it looks simple but somehow i wanted to tie this to
>> the enums we defined in sample array, so ya will check one more time if
>> it doesn't really makes any sense will clean it up.
>>
>>
>>>> in engine_group_busyness_read? See comment at __xe_pmu_event_read below.
>>>>
>>>> +
>>>> +static void xe_pmu_event_destroy(struct perf_event *event)
>>>> +{
>>>> + struct xe_device *xe =
>>>> + container_of(event->pmu, typeof(*xe), pmu.base);
>>>> +
>>>> + drm_WARN_ON(&xe->drm, event->parent);
>>>> +
>>>> + drm_dev_put(&xe->drm);
>>>> +}
>>>> +
>>>> +static u64 __engine_group_busyness_read(struct xe_gt *gt, int sample_type)
>>>> +{
>>>> + u64 val = 0;
>>> No need to initialize here I think. We are not really expecting to drop
>>> into the default case, which should be caught much before we enter this
>>> function.
>>>
>>>> +
>>>> + switch (sample_type) {
>>>> + case __XE_SAMPLE_RENDER_GROUP_BUSY:
>>>> + val = xe_mmio_read32(gt, XE_OAG_RENDER_BUSY_FREE);
>>>> + break;
>>>> + case __XE_SAMPLE_COPY_GROUP_BUSY:
>>>> + val = xe_mmio_read32(gt, XE_OAG_BLT_BUSY_FREE);
>>>> + break;
>>>> + case __XE_SAMPLE_MEDIA_GROUP_BUSY:
>>>> + val = xe_mmio_read32(gt, XE_OAG_ANY_MEDIA_FF_BUSY_FREE);
>>>> + break;
>>>> + case __XE_SAMPLE_ANY_ENGINE_GROUP_BUSY:
>>>> + val = xe_mmio_read32(gt, XE_OAG_RC0_ANY_ENGINE_BUSY_FREE);
>>>> + break;
>>>> + default:
>>>> + drm_warn(>->tile->xe->drm, "unknown pmu event\n");
>>>> + }
>>>> +
>>>> + return xe_gt_clock_cycles_to_ns(gt, val * 16);
>>>> +}
>>>> +
>>>> +static u64 engine_group_busyness_read(struct xe_gt *gt, u64 config)
>>>> +{
>>>> + int sample_type = engine_busyness_sample_type(config);
>>>>
>>>>
>>>> If config is event->attr.config, this can just be 'config_counter(config) - 1'.
>>>> See comment at __xe_pmu_event_read below.
>>>>
>>>> + const unsigned int gt_id = gt->info.id;
>>>> + struct xe_device *xe = gt->tile->xe;
>>>> + struct xe_pmu *pmu = &xe->pmu;
>>>> + unsigned long flags;
>>>> + bool device_awake;
>>>> + u64 val;
>>>> +
>>>> + device_awake = xe_device_mem_access_get_if_ongoing(xe);
>>>> + if (device_awake) {
>>>> + XE_WARN_ON(xe_force_wake_get(gt_to_fw(gt), XE_FW_GT));
>>>> + val = __engine_group_busyness_read(gt, sample_type);
>>>> + XE_WARN_ON(xe_force_wake_put(gt_to_fw(gt), XE_FW_GT));
>>>> + xe_device_mem_access_put(xe);
>>>> + }
>>>> +
>>>> + spin_lock_irqsave(&pmu->lock, flags);
>>>> +
>>>> + if (device_awake)
>>>> + pmu->sample[gt_id][sample_type] = val;
>>>> + else
>>>> + val = pmu->sample[gt_id][sample_type];
>>>> +
>>>> + spin_unlock_irqrestore(&pmu->lock, flags);
>>>> +
>>>> + return val;
>>>> +}
>>>> +
>>>> +static void engine_group_busyness_store(struct xe_gt *gt)
>>>> +{
>>>> + struct xe_pmu *pmu = >->tile->xe->pmu;
>>>> + unsigned int gt_id = gt->info.id;
>>>> + unsigned long flags;
>>>> + int i;
>>>> +
>>>> + spin_lock_irqsave(&pmu->lock, flags);
>>>> +
>>>> + for (i = __XE_SAMPLE_RENDER_GROUP_BUSY; i <= __XE_SAMPLE_ANY_ENGINE_GROUP_BUSY; i++) {
>>>> + pmu->sample[gt_id][i] = __engine_group_busyness_read(gt, i);
>>>>
>>>>
>>>> This is not quite right. At the minimum we need to take forcewake
>>>> here. Also since this is called in both suspend and runtime_suspend code
>>>> paths we might also need to the take the runtime_pm reference.
>>>>
>>>> The pm reference and forcewake are already taken in suspend paths hence
>>>> didn't add here again as this is called only from those paths.
>>>>
>>>> check xe_gt_suspend.
>>> Sorry, you are right, I missed it. So this is fine.
>>>
>>>
>>>>
>>>> I think the simplest might be to just construct 'config'
>>>> (event->attr.config) here and call engine_group_busyness_read? Something
>>>> like:
>>>>
>>>> for (i = __XE_SAMPLE_RENDER_GROUP_BUSY; i <= __XE_SAMPLE_ANY_ENGINE_GROUP_BUSY; i++) {
>>>> config = ; // Construct config using gt_id and i
>>>> engine_group_busyness_read(gt, i);
>>>> }
>>>>
>>>> This will automatically save the read values in pmu->sample[][] if the
>>>> device is awake. Thoughts?
>>>>
>>>> I think this is best kept separate from usual read paths(which are
>>>> atomic) didn't want to club them. Also because forcewakes and pm
>>>> reference are taken separately in suspend path.
>>> Sure, no changes needed here. Just get rid of the braces to keep checkpatch
>>> happy.
>>>
>>>
>>>>
>>>> + }
>>>> +
>>>> + spin_unlock_irqrestore(&pmu->lock, flags);
>>>> +}
>>>> +
>>>> +static int
>>>> +config_status(struct xe_device *xe, u64 config)
>>>> +{
>>>> + unsigned int max_gt_id = xe->info.gt_count > 1 ? 1 : 0;
>>>>
>>>>
>>>> What is this for? See below.
>>>>
>>>> reminiscent of my previous code, will clean it up.
>>>>
>>>>
>>>>
>>>> + unsigned int gt_id = config_gt_id(config);
>>>> + struct xe_gt *gt = xe_device_get_gt(xe, gt_id);
>>>> +
>>>> + if (gt_id > max_gt_id)
>>>>
>>>>
>>>> Maybe this can just be:
>>>>
>>>> if (gt_id >= XE_PMU_MAX_GT)
>>>>
>>>> + return -ENOENT;
>>>> +
>>>> + switch (config_counter(config)) {
>>>> + case XE_PMU_INTERRUPTS(0):
>>>> + if (gt_id)
>>>> + return -ENOENT;
>>>> + break;
>>>> + case XE_PMU_RENDER_GROUP_BUSY(0):
>>>> + case XE_PMU_COPY_GROUP_BUSY(0):
>>>> + case XE_PMU_ANY_ENGINE_GROUP_BUSY(0):
>>>> + if (gt->info.type == XE_GT_TYPE_MEDIA)
>>>> + return -ENOENT;
>>>> + break;
>>>> + case XE_PMU_MEDIA_GROUP_BUSY(0):
>>>> + if (!(gt->info.engine_mask & (BIT(XE_HW_ENGINE_VCS0) | BIT(XE_HW_ENGINE_VECS0))))
>>>> + return -ENOENT;
>>>> + break;
>>>> + default:
>>>> + return -ENOENT;
>>>> + }
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int xe_pmu_event_init(struct perf_event *event)
>>>> +{
>>>> + struct xe_device *xe =
>>>> + container_of(event->pmu, typeof(*xe), pmu.base);
>>>> + struct xe_pmu *pmu = &xe->pmu;
>>>> + int ret;
>>>> +
>>>> + if (pmu->closed)
>>>> + return -ENODEV;
>>>> +
>>>> + if (event->attr.type != event->pmu->type)
>>>> + return -ENOENT;
>>>> +
>>>> + /* unsupported modes and filters */
>>>> + if (event->attr.sample_period) /* no sampling */
>>>> + return -EINVAL;
>>>> +
>>>> + if (has_branch_stack(event))
>>>> + return -EOPNOTSUPP;
>>>> +
>>>> + if (event->cpu < 0)
>>>> + return -EINVAL;
>>>> +
>>>> + /* only allow running on one cpu at a time */
>>>> + if (!cpumask_test_cpu(event->cpu, &xe_pmu_cpumask))
>>>> + return -EINVAL;
>>>> +
>>>> + ret = config_status(xe, event->attr.config);
>>>> + if (ret)
>>>> + return ret;
>>>> +
>>>> + if (!event->parent) {
>>>> + drm_dev_get(&xe->drm);
>>>> + event->destroy = xe_pmu_event_destroy;
>>>> + }
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static u64 __xe_pmu_event_read(struct perf_event *event)
>>>> +{
>>>> + struct xe_device *xe =
>>>> + container_of(event->pmu, typeof(*xe), pmu.base);
>>>> + const unsigned int gt_id = config_gt_id(event->attr.config);
>>>> + const u64 config = config_counter(event->attr.config);
>>>>
>>>>
>>>> Probably nit but this config being different from event->attr.config is
>>>> confusing. Let's use 'event->attr.config' throughout as argument to
>>>> functions and use config_counter() to get rid of gt_id. So get rid of this
>>>> config variable.
>>>>
>>>> + struct xe_gt *gt = xe_device_get_gt(xe, gt_id);
>>>> + struct xe_pmu *pmu = &xe->pmu;
>>>> + u64 val = 0;
>>>> +
>>>> + switch (config) {
>>>>
>>>>
>>>> switch (config_counter(event->attr.config))
>>>>
>>>> + case XE_PMU_INTERRUPTS(0):
>>>> + val = READ_ONCE(pmu->irq_count);
>>>> + break;
>>>> + case XE_PMU_RENDER_GROUP_BUSY(0):
>>>> + case XE_PMU_COPY_GROUP_BUSY(0):
>>>> + case XE_PMU_ANY_ENGINE_GROUP_BUSY(0):
>>>> + case XE_PMU_MEDIA_GROUP_BUSY(0):
>>>> + val = engine_group_busyness_read(gt, config);
>>>>
>>>>
>>>> engine_group_busyness_read(gt, event->attr.config);
>>>>
>>>> hmmm ok.
>>>>
>>>>
>>>>
>>>> Also, need a default case.
>>>>
>>>> + }
>>>> +
>>>> + return val;
>>>> +}
>>>> +
>>>> +static void xe_pmu_event_read(struct perf_event *event)
>>>> +{
>>>> + struct xe_device *xe =
>>>> + container_of(event->pmu, typeof(*xe), pmu.base);
>>>> + struct hw_perf_event *hwc = &event->hw;
>>>> + struct xe_pmu *pmu = &xe->pmu;
>>>> + u64 prev, new;
>>>> +
>>>> + if (pmu->closed) {
>>>> + event->hw.state = PERF_HES_STOPPED;
>>>> + return;
>>>> + }
>>>> +again:
>>>> + prev = local64_read(&hwc->prev_count);
>>>> + new = __xe_pmu_event_read(event);
>>>> +
>>>> + if (local64_cmpxchg(&hwc->prev_count, prev, new) != prev)
>>>> + goto again;
>>>> +
>>>> + local64_add(new - prev, &event->count);
>>>> +}
>>>> +
>>>> +static void xe_pmu_enable(struct perf_event *event)
>>>> +{
>
> The i915_pmu code checks which event is requested here and accordingly sets pmu->enable (which doesn't seem to be defined here yet). Any reason we are not doing this yet?
in i915 pmu->enable is only used by events for which there is an internal timer sampler
which periodically samples those events, this series is not adding such events.
Thanks,
Aravind.
>
> Thanks,
>
> Vinay.
>
>>>> + /*
>>>> + * Store the current counter value so we can report the correct delta
>>>> + * for all listeners. Even when the event was already enabled and has
>>>> + * an existing non-zero value.
>>>> + */
>>>> + local64_set(&event->hw.prev_count, __xe_pmu_event_read(event));
>>>>
>>>>
>>>> Right now nothing is being enabled here (unlike i915) so the function name
>>>> xe_pmu_enable looks weird. Not sure, maybe leave as is for when things get
>>>> added in the future?
>>>>
>>>> +static int xe_pmu_cpu_online(unsigned int cpu, struct hlist_node *node)
>>>> +{
>>>> + struct xe_pmu *pmu = hlist_entry_safe(node, typeof(*pmu), cpuhp.node);
>>>> +
>>>> + BUG_ON(!pmu->base.event_init);
>>>> +
>>>> + /* Select the first online CPU as a designated reader. */
>>>> + if (cpumask_empty(&xe_pmu_cpumask))
>>>> + cpumask_set_cpu(cpu, &xe_pmu_cpumask);
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int xe_pmu_cpu_offline(unsigned int cpu, struct hlist_node *node)
>>>> +{
>>>> + struct xe_pmu *pmu = hlist_entry_safe(node, typeof(*pmu), cpuhp.node);
>>>> + unsigned int target = xe_pmu_target_cpu;
>>>> +
>>>> + BUG_ON(!pmu->base.event_init);
>>>>
>>>>
>>>> nit but wondering if we should remove these two BUG_ON's (and save a couple
>>>> of checkpatch warnings even though the BUG_ON's are in i915) and just do
>>>> something like:
>>>>
>>>> if (!pmu->base.event_init)
>>>> return 0;
>>>>
>>>> The reason for the BUG_ON's seems to be that these functions can be called
>>>> after module_init but before probe.
>>>>
>>>> xe_pmu_cpu_online() doesn't depend on pmu at all so looks like the BUG_ON
>>>> can just be dropped?
>>>>
>>>> the xe_pmu_cpu_online/offline are not invoked when they are registered with
>>>> cpuhp_setup_state_multi, but rather when cpuhp_state_add_instance() is called
>>>> which is done post the PMU is initialized hence the check for BUG_ON.
>>> cpuhp_setup_state_multi is called at module_init
>>> time. cpuhp_state_add_instance is called from xe_pmu_register, i.e. during
>>> device probe when pmu->base.event_init is already initialized. Therefore
>>> seems even less reason to have the BUG_ON's.
>> that is true even, so will remove the BUG_ON.
>>> Just a few minor issues left now so I am hoping we can wrap this marathon
>>> review up soon :)
>> ya i'm waiting for the same :)
>>
>> Thanks,
>> Aravind.
>>> Thanks.
>>> --
>>> Ashutosh
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