[PATCH v13 7/7] drm/xe/pmu: Add GT C6 events
Riana Tauro
riana.tauro at intel.com
Tue Jan 21 06:16:45 UTC 2025
Hi Lucas
On 1/17/2025 4:37 AM, Lucas De Marchi wrote:
> From: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
>
> Provide a PMU interface for GT C6 residency counters. The implementation
> is ported over from the i915 PMU code. Residency is provided in units of
> ms(like sysfs entry in - /sys/class/drm/card0/device/tile0/gt0/gtidle).
>
> Sample usage and output:
>
> $ perf list | grep gt-c6
> xe_0000_00_02.0/gt-c6-residency/ [Kernel PMU event]
>
> $ tail /sys/bus/event_source/devices/xe_0000_00_02.0/events/gt-c6-residency*
> ==> /sys/bus/event_source/devices/xe_0000_00_02.0/events/gt-c6-residency <==
> event=0x01
>
> ==> /sys/bus/event_source/devices/xe_0000_00_02.0/events/gt-c6-residency.unit <==
> ms
>
> $ perf stat -e xe_0000_00_02.0/gt-c6-residency,gt=0/ -I1000
> # time counts unit events
> 1.001196056 1,001 ms xe_0000_00_02.0/gt-c6-residency,gt=0/
> 2.005216219 1,003 ms xe_0000_00_02.0/gt-c6-residency,gt=0/
>
> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar at intel.com>
> Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
> ---
>
> Besides the rebase, that changed a lot how the event was added,
> here is a summary of other changes:
>
> - Use xe_pm_runtime_get_if_active() when reading
> xe_gt_idle_residency_msec() as there's not guarantee it will not be
> suspended anymore by the time it reads the counter
>
> - Drop sample[] from the pmu struct and only use the prev/counter from
> the perf_event struct. This avoids mixing the counter reported to 2
> separate clients.
>
> - Drop time ktime helpers and just use what's provided by
> include/linux/ktime.h
>
> drivers/gpu/drm/xe/xe_pmu.c | 56 +++++++++++++++++++++++++++++++------
> 1 file changed, 48 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/gpu/drm/xe/xe_pmu.c b/drivers/gpu/drm/xe/xe_pmu.c
> index c2af82ec3f793..37df9d3cc110c 100644
> --- a/drivers/gpu/drm/xe/xe_pmu.c
> +++ b/drivers/gpu/drm/xe/xe_pmu.c
> @@ -11,6 +11,7 @@
> #include "xe_device.h"
> #include "xe_force_wake.h"
> #include "xe_gt_clock.h"
> +#include "xe_gt_idle.h"
> #include "xe_gt_printk.h"
> #include "xe_mmio.h"
> #include "xe_macros.h"
> @@ -117,16 +118,50 @@ static int xe_pmu_event_init(struct perf_event *event)
> return 0;
> }
>
> -static u64 __xe_pmu_event_read(struct perf_event *event)
> +static u64 read_gt_c6_residency(struct xe_pmu *pmu, struct xe_gt *gt, u64 prev)
> {
> - struct xe_device *xe = container_of(event->pmu, typeof(*xe), pmu.base);
> + struct xe_device *xe = gt_to_xe(gt);
> + unsigned long flags;
> + ktime_t t0;
> + s64 delta;
> +
> + if (xe_pm_runtime_get_if_active(xe)) {
Seeing this lockdep warn on reading gt-c6-residency
[ 5032.731663] =============================
[ 5032.735699] [ BUG: Invalid wait context ]
[ 5032.745260] -----------------------------
[ 5032.749300] perf/3320 is trying to lock:
[ 5032.753260] ffff888105f2c238 (&dev->power.lock){-.-.}-{3:3}, at:
pm_runtime_get_conditional+0x26/0xb0
[ 5032.762528] other info that might help us debug this:
[ 5032.767613] context-{5:5}
[ 5032.770262] 3 locks held by perf/3320:
[ 5032.774045] #0: ffff88846f632048 (&cpuctx_mutex){+.+.}-{4:4}, at:
perf_event_ctx_lock_nested+0xba/0x230
[ 5032.783587] #1: ffff8881037482c0 (&event->child_mutex){+.+.}-{4:4},
at: perf_event_for_each_child+0x39/0x90
[ 5032.793480] #2: ffff88846f631fb8 (&cpuctx_lock){....}-{2:2}, at:
event_function+0x57/0x120
[ 5032.829907] Call Trace:
[ 5032.832384] <TASK>
[ 5032.834513] dump_stack_lvl+0x81/0xc0
[ 5032.838236] dump_stack+0x10/0x20
[ 5032.841586] __lock_acquire+0xa5a/0x2550
[ 5032.845548] lock_acquire+0xc3/0x2f0
[ 5032.849156] ? pm_runtime_get_conditional+0x26/0xb0
[ 5032.854066] ? is_bpf_text_address+0x71/0x120
[ 5032.858487] _raw_spin_lock_irqsave+0x4b/0x70
[ 5032.862892] ? pm_runtime_get_conditional+0x26/0xb0
[ 5032.867814] pm_runtime_get_conditional+0x26/0xb0
[ 5032.872570] pm_runtime_get_if_active+0x13/0x20
[ 5032.877141] xe_pm_runtime_get_if_active+0x12/0x20 [xe]
[ 5032.882545] __xe_pmu_event_read+0x116/0x2a0 [xe]
Thanks
Riana
> + u64 val = xe_gt_idle_residency_msec(>->gtidle);
> +
> + xe_pm_runtime_put(xe);
> +
> + return val;
> + }
> +
> + /*
> + * Estimate the idle residency by looking at the time the device was
> + * suspended: should be good enough as long as the sampling frequency is
> + * 2x or more than the suspend frequency.
> + */
> + raw_spin_lock_irqsave(&pmu->lock, flags);
> + t0 = pmu->suspend_timestamp[gt->info.id];
> + raw_spin_unlock_irqrestore(&pmu->lock, flags);
> +
> + delta = ktime_ms_delta(ktime_get(), t0);
> +
> + return prev + delta;
> +}
> +
> +static u64 __xe_pmu_event_read(struct perf_event *event, u64 prev)
> +{
> + struct xe_pmu *pmu = container_of(event->pmu, typeof(*pmu), base);
> + struct xe_device *xe = container_of(pmu, typeof(*xe), pmu);
> struct xe_gt *gt = event_to_gt(event);
> - u64 val = 0;
>
> if (!gt)
> - return 0;
> + return prev;
> +
> + switch (config_to_event_id(event->attr.config)) {
> + case XE_PMU_EVENT_GT_C6_RESIDENCY:
> + return read_gt_c6_residency(pmu, gt, prev);
> + }
>
> - return val;
> + return prev;
> }
>
> static void xe_pmu_event_update(struct perf_event *event)
> @@ -136,10 +171,11 @@ static void xe_pmu_event_update(struct perf_event *event)
>
> prev = local64_read(&hwc->prev_count);
> do {
> - new = __xe_pmu_event_read(event);
> + new = __xe_pmu_event_read(event, prev);
> } while (!local64_try_cmpxchg(&hwc->prev_count, &prev, new));
>
> - local64_add(new - prev, &event->count);
> + if (new > prev)
> + local64_add(new - prev, &event->count);
> }
>
> static void xe_pmu_event_read(struct perf_event *event)
> @@ -162,7 +198,7 @@ static void xe_pmu_enable(struct perf_event *event)
> * 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));
> + local64_set(&event->hw.prev_count, __xe_pmu_event_read(event, 0));
> }
>
> static void xe_pmu_event_start(struct perf_event *event, int flags)
> @@ -267,6 +303,10 @@ static const struct attribute_group pmu_events_attr_group = {
>
> static void set_supported_events(struct xe_pmu *pmu)
> {
> + struct xe_device *xe = container_of(pmu, typeof(*xe), pmu);
> +
> + if (!xe->info.skip_guc_pc)
> + pmu->supported_events |= BIT_ULL(XE_PMU_EVENT_GT_C6_RESIDENCY);
> }
>
> /**
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