[Intel-xe] [RFC PATCH 1/3] drm/xe: add a new sysfs directory for gpu idle properties

Nilawar, Badal badal.nilawar at intel.com
Thu May 4 12:30:39 UTC 2023


Hi Riana,

On 03-05-2023 12:12, Riana Tauro wrote:
> Add a new sysfs directory under devices/gt#/ called gpu_idle
> to contain idle properties of GT such as rc_status, rc6_residency.
> 
> Signed-off-by: Riana Tauro <riana.tauro at intel.com>
> ---
>   drivers/gpu/drm/xe/Makefile        |   1 +
>   drivers/gpu/drm/xe/xe_gt.c         |   5 +
>   drivers/gpu/drm/xe/xe_gt_types.h   |   4 +
>   drivers/gpu/drm/xe/xe_idle.c       | 151 +++++++++++++++++++++++++++++
>   drivers/gpu/drm/xe/xe_idle.h       |  13 +++
>   drivers/gpu/drm/xe/xe_idle_types.h |  32 ++++++
>   6 files changed, 206 insertions(+)
>   create mode 100644 drivers/gpu/drm/xe/xe_idle.c
>   create mode 100644 drivers/gpu/drm/xe/xe_idle.h
>   create mode 100644 drivers/gpu/drm/xe/xe_idle_types.h
> 
> diff --git a/drivers/gpu/drm/xe/Makefile b/drivers/gpu/drm/xe/Makefile
> index ee4a95beec20..5d1b837ad001 100644
> --- a/drivers/gpu/drm/xe/Makefile
> +++ b/drivers/gpu/drm/xe/Makefile
> @@ -61,6 +61,7 @@ xe-y += xe_bb.o \
>   	xe_hw_fence.o \
>   	xe_huc.o \
>   	xe_huc_debugfs.o \
> +	xe_idle.o \
>   	xe_irq.o \
>   	xe_lrc.o \
>   	xe_migrate.o \
> diff --git a/drivers/gpu/drm/xe/xe_gt.c b/drivers/gpu/drm/xe/xe_gt.c
> index 4186f7f0d42f..be802e6a0054 100644
> --- a/drivers/gpu/drm/xe/xe_gt.c
> +++ b/drivers/gpu/drm/xe/xe_gt.c
> @@ -25,6 +25,7 @@
>   #include "xe_gt_topology.h"
>   #include "xe_guc_engine_types.h"
>   #include "xe_hw_fence.h"
> +#include "xe_idle.h"
>   #include "xe_irq.h"
>   #include "xe_lrc.h"
>   #include "xe_map.h"
> @@ -381,6 +382,10 @@ static int gt_fw_domain_init(struct xe_gt *gt)
>   	if (err)
>   		goto err_force_wake;
>   
> +	err = xe_idle_init(&gt->idle);
> +	if (err)
> +		goto err_force_wake;
> +
>   	/* XXX: Fake that we pull the engine mask from hwconfig blob */
>   	gt->info.engine_mask = gt->info.__engine_mask;
>   
> diff --git a/drivers/gpu/drm/xe/xe_gt_types.h b/drivers/gpu/drm/xe/xe_gt_types.h
> index 7c47d67aa8be..1f2a55026c0c 100644
> --- a/drivers/gpu/drm/xe/xe_gt_types.h
> +++ b/drivers/gpu/drm/xe/xe_gt_types.h
> @@ -9,6 +9,7 @@
>   #include "xe_force_wake_types.h"
>   #include "xe_hw_engine_types.h"
>   #include "xe_hw_fence_types.h"
> +#include "xe_idle_types.h"
>   #include "xe_reg_sr_types.h"
>   #include "xe_sa_types.h"
>   #include "xe_uc_types.h"
> @@ -287,6 +288,9 @@ struct xe_gt {
>   	/** @uc: micro controllers on the GT */
>   	struct xe_uc uc;
>   
> +	/** @idle: render c state properties of GT */
> +	struct xe_idle idle;
> +
>   	/** @engine_ops: submission backend engine operations */
>   	const struct xe_engine_ops *engine_ops;
>   
> diff --git a/drivers/gpu/drm/xe/xe_idle.c b/drivers/gpu/drm/xe/xe_idle.c
> new file mode 100644
> index 000000000000..231bdb45a6b7
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_idle.c
> @@ -0,0 +1,151 @@
> +// SPDX-License-Identifier: MIT
> +/*
> + * Copyright © 2023 Intel Corporation
> + */
> +
> +#include <drm/drm_managed.h>
> +#include "regs/xe_gt_regs.h"
> +
> +#include "xe_device.h"
> +#include "xe_gt.h"
> +#include "xe_idle.h"
> +#include "xe_mmio.h"
> +
> +/*
> + * Render-C States:
> + * ================
> + *
> + * Render-C states is also a GuC PC feature that is now enabled in Xe for
> + * all platforms.
> + *
> + * RC6 : RC6 is a special power stage which allows the GPU to enter a very
> + * low-voltage mode when idle. This stage is entered automatically when the GPU is idle
> + * when RC6 support is enabled, and as soon as new workload arises
> + * GPU wakes up automatically as well.
> + *
> + * Xe provides a sysfs API for Render-C States:
> + *
> + * device/gt#/gpu_idle/rc* *read-only* files:
> + * - rc_status: Provide the actual immediate status of Render-C: (rc0 or rc6)
> + * - rc6_residency: Provide the rc6_residency in units of 1.28 uSec
> + *		    Prone to overflows.
> + */
> +
> +static struct xe_gt *idle_to_gt(struct xe_idle *idle)
> +{
> +	return container_of(idle, struct xe_gt, idle);
> +}
> +
> +static struct xe_idle *kobj_to_idle(struct kobject *kobj)
> +{
> +	return container_of(kobj, struct kobj_idle, base)->idle;
> +}
> +
> +static void xe_idle_kobj_release(struct kobject *kobj)
> +{
> +	kfree(kobj);
> +}
> +
> +static struct kobj_type xe_idle_kobj_type = {
> +	.release = xe_idle_kobj_release,
> +	.sysfs_ops = &kobj_sysfs_ops,
> +};
> +
> +static ssize_t
> +rc_status_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	struct xe_idle *idle = kobj_to_idle(kobj);
> +	struct xe_gt *gt = idle_to_gt(idle);
> +	u32 reg;
> +
> +	xe_device_mem_access_get(gt_to_xe(gt));
> +	reg = xe_mmio_read32(gt, GEN6_GT_CORE_STATUS.reg);
> +	xe_device_mem_access_put(gt_to_xe(gt));This can be abstracted by adding variable xe_reg to xe_idle structure, 
to hold GT_CORE_STATUS reg, which can be initialized xe_idle_init 
function. > +
> +	switch (REG_FIELD_GET(RCN_MASK, reg)) {
> +	case GT_RC6:
> +		return sysfs_emit(buf, "rc6\n");
> +	case GT_RC0:
> +		return sysfs_emit(buf, "rc0\n");
> +	default:
> +		return -ENOENT;
> +	}
> +}
> +
> +static const struct kobj_attribute rc_status =
> +__ATTR(rc_status, 0444, rc_status_show, NULL);
> +
> +static ssize_t
> +rc6_residency_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	struct xe_idle *idle = kobj_to_idle(kobj);
> +	struct xe_gt *gt = idle_to_gt(idle);
> +	u32 reg;
> +	ssize_t ret;
> +
> +	xe_device_mem_access_get(gt_to_xe(gt));
> +	ret = xe_force_wake_get(gt_to_fw(gt), XE_FORCEWAKE_ALL);
> +	if (ret)
> +		goto out;
> +
> +	reg = xe_mmio_read32(gt, GEN6_GT_GFX_RC6.reg);
As mentioned in other patch this register does not fall under any of the 
forcewake domain so forcewake can be avoided here.
Abstraction is applicable here has well.
> +	ret = sysfs_emit(buf, "%u\n", reg);
> +
> +	XE_WARN_ON(xe_force_wake_put(gt_to_fw(gt), XE_FORCEWAKE_ALL));
> +out:
> +	xe_device_mem_access_put(gt_to_xe(gt));
> +	return ret;
> +}
> +
> +static const struct kobj_attribute rc6_residency =
> +__ATTR(rc6_residency, 0444, rc6_residency_show, NULL);
Good to use __ATTR_RO or DEV_ATTR_RO here.

Regards,
Badal
> +
> +static const struct attribute *idle_attrs[] = {
> +	&rc_status.attr,
> +	&rc6_residency.attr,
> +	NULL,
> +};
> +
> +static void idle_fini(struct drm_device *drm, void *arg)
> +{
> +	struct kobj_idle *kobj_idle = arg;
> +
> +	sysfs_remove_files(&kobj_idle->base, idle_attrs);
> +	kobject_put(&kobj_idle->base);
> +}
> +
> +int xe_idle_init(struct xe_idle *idle)
> +{
> +	struct xe_gt *gt = idle_to_gt(idle);
> +	struct xe_device *xe = gt_to_xe(gt);
> +	struct kobj_idle *kobj_idle;
> +	int err;
> +
> +	kobj_idle = kzalloc(sizeof(*kobj_idle), GFP_KERNEL);
> +
> +	if (!kobj_idle)
> +		return -ENOMEM;
> +
> +	err = kobject_init_and_add(&kobj_idle->base, &xe_idle_kobj_type, gt->sysfs, "gpu_idle");
> +	if (err)
> +		goto exit_kobj;
> +
> +	kobj_idle->idle = idle;
> +
> +	err = sysfs_create_files(&kobj_idle->base, idle_attrs);
> +	if (err)
> +		goto exit_kobj;
> +
> +	err = drmm_add_action_or_reset(&xe->drm, idle_fini, kobj_idle);
> +	if (err)
> +		goto exit;
> +
> +	return 0;
> +
> +exit:
> +	sysfs_remove_files(&kobj_idle->base, idle_attrs);
> +
> +exit_kobj:
> +	kobject_put(&kobj_idle->base);
> +	return err;
> +}
> diff --git a/drivers/gpu/drm/xe/xe_idle.h b/drivers/gpu/drm/xe/xe_idle.h
> new file mode 100644
> index 000000000000..77928a31cecd
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_idle.h
> @@ -0,0 +1,13 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2023 Intel Corporation
> + */
> +
> +#ifndef _XE_IDLE_H_
> +#define _XE_IDLE_H_
> +
> +#include "xe_idle_types.h"
> +
> +int xe_idle_init(struct xe_idle *idle);
> +
> +#endif /* _XE_IDLE_H_ */
> diff --git a/drivers/gpu/drm/xe/xe_idle_types.h b/drivers/gpu/drm/xe/xe_idle_types.h
> new file mode 100644
> index 000000000000..94377610c56c
> --- /dev/null
> +++ b/drivers/gpu/drm/xe/xe_idle_types.h
> @@ -0,0 +1,32 @@
> +/* SPDX-License-Identifier: MIT */
> +/*
> + * Copyright © 2023 Intel Corporation
> + */
> +
> +#ifndef _XE_IDLE_TYPES_H_
> +#define _XE_IDLE_TYPES_H_
> +
> +#include <linux/kobject.h>
> +#include <linux/types.h>
> +
> +/**
> + * struct xe_idle - A struct that contains gpu idle properties
> + */
> +struct xe_idle {
> +	/** @prev_rc6_residency: previous rc6 residency counter */
> +	u64 prev_rc6_residency;
> +	/** @cur_rc6_residency: raw driver copy of rc6 residency */
> +	u64 cur_rc6_residency;
> +};
> +
> +/**
> + * struct kobj_idle - A kobject struct that connects the kobject and xe_idle
> + */
> +struct kobj_idle {
> +	/** @base: The actual kobject */
> +	struct kobject base;
> +	/** @idle: A pointer to the struct xe_idle itself */
> +	struct xe_idle *idle;
> +};
> +#endif /* _XE_IDLE_TYPES_H_ */
> +


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