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

[Grzegorzek, Dominik]

On Fri, 2024-09-27 at 07:18 +0200, Zbigniew Kempczyński wrote:
> 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

Noted, keeping function without unconditional usage is unwelcome.
If so, I would just define those function localy in the test having in mind(or
in the comment) that it could be moved whenever KMD part of eudebug gets upstreamed.
Setting engine properies ins't really sth exculsive to eu debugger, thus I think lib/xe_eudebug
isn't a good place for that.

Regards,
Dominik
> 
> > 
> > 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,
> >