[PATCH i-g-t 1/2] lib/xe_eudebug: Introduce preempt_timeout helpers

[Zbigniew Kempczyński]

On Thu, Sep 26, 2024 at 04:54:53PM +0200, Grzegorzek, Dominik wrote:
> On Thu, 2024-09-26 at 14:18 +0200, Dominik Karol Piątkowski wrote:
> > This patch introduces preempt_timeout helpers:
> >  - xe_eudebug_set_preempt_timeout_to_max
> >    Sets preempt_timeout_us for given engine_class to maximum.
> >  - xe_eudebug_restore_preempt_timeout
> >    Sets preempt_timeout_us for given engine_class to previous value.
> > 
> 
> I think this should really go to igt_sysfs.c. And in sligtly different form:
> How about sth like:

We're compiling lib/xe_eudebug.c conditionally so I wouldn't pollute igt_sysfs.c
with eudebug code (at least yet).

--
Zbigniew

> 
> igt_sysfs_engine_set_property(engines_fd, "preempt_timeout_us", value);
> igt_sysfs_engine_set_property_bound(engines_fd, "preempt_timeout_us", max);
> 
> ,where max is a bool variable which tells whether it should be min or max.
> 
> To find engines_fd xe_sysfs_engine_open could be used.
> 
> Regards,
> Dominik
> 
> > Signed-off-by: Dominik Karol Piątkowski <dominik.karol.piatkowski at intel.com>
> > ---
> >  lib/xe/xe_eudebug.c | 120 ++++++++++++++++++++++++++++++++++++++++++++
> >  lib/xe/xe_eudebug.h |   3 ++
> >  2 files changed, 123 insertions(+)
> > 
> > diff --git a/lib/xe/xe_eudebug.c b/lib/xe/xe_eudebug.c
> > index 2c7cd2ae1..229f9e6a1 100644
> > --- a/lib/xe/xe_eudebug.c
> > +++ b/lib/xe/xe_eudebug.c
> > @@ -16,6 +16,7 @@
> >  #include "intel_pat.h"
> >  #include "xe_eudebug.h"
> >  #include "xe_ioctl.h"
> > +#include "xe_drm.h"
> >  
> >  struct event_trigger {
> >  	xe_eudebug_trigger_fn fn;
> > @@ -1717,6 +1718,125 @@ bool xe_eudebug_enable(int fd, bool enable)
> >  	return old;
> >  }
> >  
> > +/**
> > + * xe_eudebug_set_preempt_timeout_to_max
> > + * @fd: xe client
> > + * @engine_class: engine class to modify (drm_xe_engine_class_instance->engine_class)
> > + * @value: pointer to variable to store previous preempt_timeout value in, needed for restore
> > + *
> > + * Sets preempt_timeout_us for given engine_class to maximum.
> > + *
> > + * Returns: true on success, false on failure.
> > + */
> > +bool xe_eudebug_set_preempt_timeout_to_max(int fd, uint16_t engine_class, uint32_t *value)
> > +{
> > +	int engines_fd;
> > +	int gt_fd;
> > +	uint32_t max_value;
> > +
> > +	igt_assert(engine_class == DRM_XE_ENGINE_CLASS_RENDER ||
> > +		   engine_class == DRM_XE_ENGINE_CLASS_COMPUTE);
> > +
> > +	gt_fd = xe_sysfs_gt_open(fd, 0);
> > +	if (gt_fd == -1) {
> > +		igt_debug("Failed to open gt.\n");
> > +
> > +		return false;
> > +	}
> > +
> > +	if (engine_class == DRM_XE_ENGINE_CLASS_RENDER)
> > +		engines_fd = openat(gt_fd, "engines/rcs", O_RDONLY);
> > +	else
> > +		engines_fd = openat(gt_fd, "engines/ccs", O_RDONLY);
> > +
> > +	if (engines_fd == -1) {
> > +		igt_debug("Failed to open engine class.\n");
> > +		close(gt_fd);
> > +
> > +		return false;
> > +	}
> > +
> > +	if (!__igt_sysfs_get_u32(engines_fd, "preempt_timeout_us", value)) {
> > +		igt_debug("Failed to read preempt_timeout_us.\n");
> > +		close(engines_fd);
> > +		close(gt_fd);
> > +
> > +		return false;
> > +	}
> > +
> > +	if (!__igt_sysfs_get_u32(engines_fd, "preempt_timeout_max", &max_value)) {
> > +		igt_debug("Failed to read preempt_timeout_max.\n");
> > +		close(engines_fd);
> > +		close(gt_fd);
> > +
> > +		return false;
> > +	}
> > +
> > +	if (!__igt_sysfs_set_u32(engines_fd, "preempt_timeout_us", max_value)) {
> > +		igt_debug("Failed to write preempt_timeout_us.\n");
> > +		close(engines_fd);
> > +		close(gt_fd);
> > +
> > +		return false;
> > +	}
> > +
> > +	close(engines_fd);
> > +	close(gt_fd);
> > +
> > +	return true;
> > +}
> > +
> > +/**
> > + * xe_eudebug_restore_preempt_timeout
> > + * @fd: xe client
> > + * @engine_class: engine class to modify (drm_xe_engine_class_instance->engine_class)
> > + * @value: previous preempt_timeout value
> > + *
> > + * Sets preempt_timeout_us for given engine_class to previous value.
> > + *
> > + * Returns: true on success, false on failure.
> > + */
> > +bool xe_eudebug_restore_preempt_timeout(int fd, uint16_t engine_class, uint32_t value)
> > +{
> > +	int engines_fd;
> > +	int gt_fd;
> > +
> > +	igt_assert(engine_class == DRM_XE_ENGINE_CLASS_RENDER ||
> > +		   engine_class == DRM_XE_ENGINE_CLASS_COMPUTE);
> > +
> > +	gt_fd = xe_sysfs_gt_open(fd, 0);
> > +	if (gt_fd == -1) {
> > +		igt_debug("Failed to open gt.\n");
> > +
> > +		return false;
> > +	}
> > +
> > +	if (engine_class == DRM_XE_ENGINE_CLASS_RENDER)
> > +		engines_fd = openat(gt_fd, "engines/rcs", O_RDONLY);
> > +	else
> > +		engines_fd = openat(gt_fd, "engines/ccs", O_RDONLY);
> > +
> > +	if (engines_fd == -1) {
> > +		igt_debug("Failed to open engine class.\n");
> > +		close(gt_fd);
> > +
> > +		return false;
> > +	}
> > +
> > +	if (!__igt_sysfs_set_u32(engines_fd, "preempt_timeout_us", value)) {
> > +		igt_debug("Failed to write preempt_timeout_us.\n");
> > +		close(engines_fd);
> > +		close(gt_fd);
> > +
> > +		return false;
> > +	}
> > +
> > +	close(engines_fd);
> > +	close(gt_fd);
> > +
> > +	return true;
> > +}
> > +
> >  /* Eu debugger wrappers around resource creating xe ioctls. */
> >  
> >  /**
> > diff --git a/lib/xe/xe_eudebug.h b/lib/xe/xe_eudebug.h
> > index 29ab68fee..144035862 100644
> > --- a/lib/xe/xe_eudebug.h
> > +++ b/lib/xe/xe_eudebug.h
> > @@ -167,6 +167,9 @@ void xe_eudebug_client_set_data(struct xe_eudebug_client *c, void *ptr);
> >  
> >  bool xe_eudebug_enable(int fd, bool enable);
> >  
> > +bool xe_eudebug_set_preempt_timeout_to_max(int fd, uint16_t engine_class, uint32_t *value);
> > +bool xe_eudebug_restore_preempt_timeout(int fd, uint16_t engine_class, uint32_t value);
> > +
> >  int xe_eudebug_client_open_driver(struct xe_eudebug_client *c);
> >  void xe_eudebug_client_close_driver(struct xe_eudebug_client *c, int fd);
> >  uint32_t xe_eudebug_client_vm_create(struct xe_eudebug_client *c, int fd,
>