[PATCH v2] drm/xe: GPU frequency tracing support
Lucas De Marchi
lucas.demarchi at intel.com
Mon Aug 11 21:13:59 UTC 2025
On Mon, Aug 11, 2025 at 02:04:14PM +0530, S Sebinraj wrote:
>A periodic GPU frequency monitoring and tracing program for the
>Xe driver. The implementation provides periodic sampling of
>GPU frequency through the Linux ftrace infrastructure.
>
>Key features:
>- Periodic GPU frequency sampling with configurable intervals
>- Immediate frequency change reporting via tracepoints
>- Integration with Linux ftrace subsystem under 'power' events
>- Per-GT (Graphics Technology) monitoring support
>- Dedicated workqueue for non-blocking frequency sampling
>- Configurable via CONFIG_DRM_XE_GPUFREQTRACER kernel option
>- The monitoring interval can be configured at runtime via the sysfs
> (default 5sec).
>
>The sysfs entry is at:
>/sys/module/xe/parameters/gpufreq_monitoring_interval_ms
This is actually a module parameter, which is global to all devices xe
binds to.
>
>The tracepoint is exposed at:
>/sys/kernel/debug/tracing/events/power/gpu_frequency
>
>Format: {unsigned int state, unsigned int gpu_id}
>- state: GPU frequency in KHz
>- gpu_id: GPU clock domain identifier
>
>This enables userspace tools and system monitoring applications to track
>GPU frequency changes for power management analysis, performance tuning,
>and debugging purposes.
>
>Signed-off-by: S Sebinraj <s.sebinraj at intel.com>
>---
> drivers/gpu/drm/xe/Kconfig | 22 ++
> drivers/gpu/drm/xe/Makefile | 3 +
> drivers/gpu/drm/xe/xe_device.c | 7 +
> drivers/gpu/drm/xe/xe_device_types.h | 4 +
> drivers/gpu/drm/xe/xe_gpufreqtracer.c | 292 ++++++++++++++++++++
> drivers/gpu/drm/xe/xe_gpufreqtracer.h | 30 ++
> drivers/gpu/drm/xe/xe_gpufreqtracer_trace.h | 48 ++++
> drivers/gpu/drm/xe/xe_module.c | 12 +
> drivers/gpu/drm/xe/xe_module.h | 3 +
> 9 files changed, 421 insertions(+)
> create mode 100644 drivers/gpu/drm/xe/xe_gpufreqtracer.c
> create mode 100644 drivers/gpu/drm/xe/xe_gpufreqtracer.h
> create mode 100644 drivers/gpu/drm/xe/xe_gpufreqtracer_trace.h
>
>diff --git a/drivers/gpu/drm/xe/Kconfig b/drivers/gpu/drm/xe/Kconfig
>index 714d5702dfd7..d9d07ec69875 100644
>--- a/drivers/gpu/drm/xe/Kconfig
>+++ b/drivers/gpu/drm/xe/Kconfig
>@@ -129,6 +129,28 @@ config DRM_XE_FORCE_PROBE
>
> Use "!*" to block the probe of the driver for all known devices.
>
>+config DRM_XE_GPUFREQTRACER
>+ bool "Enable XE GPU frequency tracing"
>+ depends on DRM_XE && FTRACE
>+ default n
>+ help
>+ Enable GPU frequency tracing support for Intel XE driver.
>+ This adds an ftrace tracepoint that reports GPU frequency changes
>+ at periodic boundaries (default 5 secs, configurable via the
>+ gpufreq_monitoring_interval_ms module parameter) and
>+ on direct frequency change events.
>+
>+ The monitoring interval can be configured at runtime via the sysfs module parameter:
>+ /sys/module/xe/parameters/gpufreq_monitoring_interval_ms
>+
>+ The tracepoint will be available at:
>+ /sys/kernel/debug/tracing/events/power/gpu_frequency
>+
>+ Format: {unsigned int state, unsigned int gpu_id}
>+ Where state is the frequency in KHz and gpu_id is the GPU clock domain.
>+
>+ If unsure, say N.
>+
> menu "drm/Xe Debugging"
> depends on DRM_XE
> depends on EXPERT
>diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
>index 8e0c3412a757..61d46cc4dc25 100644
>--- a/drivers/gpu/drm/xe/Makefile
>+++ b/drivers/gpu/drm/xe/Makefile
>@@ -170,6 +170,9 @@ xe-$(CONFIG_PCI_IOV) += \
> xe_sriov_pf.o \
> xe_sriov_pf_service.o
>
>+# GPU frequency tracer
>+xe-$(CONFIG_DRM_XE_GPUFREQTRACER) += xe_gpufreqtracer.o
>+
> # include helpers for tests even when XE is built-in
> ifdef CONFIG_DRM_XE_KUNIT_TEST
> xe-y += tests/xe_kunit_helpers.o
>diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
>index 57edbc63da6f..88198ceb519b 100644
>--- a/drivers/gpu/drm/xe/xe_device.c
>+++ b/drivers/gpu/drm/xe/xe_device.c
>@@ -34,6 +34,7 @@
> #include "xe_exec_queue.h"
> #include "xe_force_wake.h"
> #include "xe_ggtt.h"
>+#include "xe_gpufreqtracer.h"
> #include "xe_gsc_proxy.h"
> #include "xe_gt.h"
> #include "xe_gt_mcr.h"
>@@ -896,6 +897,12 @@ int xe_device_probe(struct xe_device *xe)
> if (err)
> return err;
>
>+#if IS_ENABLED(CONFIG_DRM_XE_GPUFREQTRACER)
>+ err = xe_gpufreqtracer_init(xe);
>+ if (err)
>+ return err;
>+#endif
>+
> err = xe_oa_init(xe);
> if (err)
> return err;
>diff --git a/drivers/gpu/drm/xe/xe_device_types.h b/drivers/gpu/drm/xe/xe_device_types.h
>index 01e8fa0d2f9f..0634dbbbdc3f 100644
>--- a/drivers/gpu/drm/xe/xe_device_types.h
>+++ b/drivers/gpu/drm/xe/xe_device_types.h
>@@ -35,6 +35,7 @@ struct dram_info;
> struct intel_display;
> struct intel_dg_nvm_dev;
> struct xe_ggtt;
>+struct xe_gpufreqtracer_data;
> struct xe_i2c;
> struct xe_pat_ops;
> struct xe_pxp;
>@@ -529,6 +530,9 @@ struct xe_device {
> /** @oa: oa observation subsystem */
> struct xe_oa oa;
>
>+ /** @gpufreqtracer_data: GPU frequency tracer data */
>+ struct xe_gpufreqtracer_data *gpufreqtracer_data;
>+
> /** @pxp: Encapsulate Protected Xe Path support */
> struct xe_pxp *pxp;
>
>diff --git a/drivers/gpu/drm/xe/xe_gpufreqtracer.c b/drivers/gpu/drm/xe/xe_gpufreqtracer.c
>new file mode 100644
>index 000000000000..07eedfb79e93
>--- /dev/null
>+++ b/drivers/gpu/drm/xe/xe_gpufreqtracer.c
>@@ -0,0 +1,292 @@
>+// SPDX-License-Identifier: GPL-2.0
>+/*
>+ * Copyright © 2025 Intel Corporation
>+ */
>+
>+#include "xe_gpufreqtracer.h"
>+
>+#include <linux/workqueue.h>
>+#include <linux/slab.h>
>+#include <linux/jiffies.h>
>+#include <linux/kernel.h>
>+#include <linux/moduleparam.h>
>+#include <linux/types.h>
>+#include <linux/container_of.h>
>+#include <linux/gfp.h>
>+#include <linux/atomic.h>
>+#include <drm/drm_managed.h>
>+
>+#include "xe_device.h"
>+#include "xe_gt.h"
>+#include "xe_gt_types.h"
>+#include "xe_guc_pc.h"
>+#include "xe_module.h"
>+
>+/* GPU frequency monitoring interval constants (in milliseconds) */
>+#define XE_GPUFREQ_MONITORING_MIN_INTERVAL_MS 100
>+#define XE_GPUFREQ_MONITORING_MAX_INTERVAL_MS 10000
>+#define XE_GPUFREQ_MONITORING_DEFAULT_INTERVAL_MS 5000
>+
>+#define CREATE_TRACE_POINTS
>+#include "xe_gpufreqtracer_trace.h"
>+
>+/**
>+ * struct xe_gpufreqtracer_gt_data - Per-GT frequency monitoring data
>+ * @gt: Reference to the GT
>+ * @delayed_work: Delayed work for periodic monitoring
>+ * @last_frequency: Last reported frequency to avoid duplicate reports
>+ * @monitoring_active: Whether monitoring is currently active
>+ */
>+struct xe_gpufreqtracer_gt_data {
>+ struct xe_gt *gt;
>+ struct delayed_work delayed_work;
>+ atomic_t last_frequency;
>+ atomic_t monitoring_active;
>+};
>+
>+/**
>+ * struct xe_gpufreqtracer_data - Per-device frequency tracer data
>+ * @xe: Reference to the XE device
>+ * @gt_data: Array of per-GT monitoring data
>+ */
>+struct xe_gpufreqtracer_data {
>+ struct xe_device *xe;
>+ struct xe_gpufreqtracer_gt_data *gt_data;
>+};
>+
>+
>+/**
>+ * xe_gpufreqtracer_sample_work - Worker function to sample GPU frequency.
>+ * @work: Pointer to the delayed_work_struct representing the scheduled work.
>+ *
>+ * This function is executed in a workqueue context to periodically sample
>+ * the GPU frequency and perform any necessary tracing or logging operations.
>+ * It reschedules itself for the next sampling interval.
>+ */
>+static void xe_gpufreqtracer_sample_work(struct work_struct *work)
this looks like a weird abstraction that creates issues (see Matt
Brost's reply) that are already a solved problem. Why can't the
userspace interested in it use perf for that? We already sample
frequency changes there. See drivers/gpu/drm/xe/xe_pmu.c
Lucas De Marchi
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