Re: [igt-dev] [PATCH v3 i-g-t 13/15] lib/i915: Add helper for non-destructive engine property updates

[Matthew Brost <matthew.brost@xxxxxxxxx>]

On Thu, Jan 13, 2022 at 11:59:45AM -0800, John.C.Harrison@xxxxxxxxx wrote:
> From: John Harrison <John.C.Harrison@xxxxxxxxx>
> 
> Various tests want to configure engine properties such as pre-emption
> timeout and heartbeat interval. Some don't bother to restore the
> original values again afterwards. So, add a helper to make it easier
> to do this.
> 
> v2: Fix for platforms with no pre-emption capability.
> 
> Signed-off-by: John Harrison <John.C.Harrison@xxxxxxxxx>

Reviewed-by: Matthew Brost <matthew.brost@xxxxxxxxx>

> ---
>  lib/i915/gem_engine_topology.c | 46 ++++++++++++++++++++++++++++++++++
>  lib/i915/gem_engine_topology.h |  9 +++++++
>  2 files changed, 55 insertions(+)
> 
> diff --git a/lib/i915/gem_engine_topology.c b/lib/i915/gem_engine_topology.c
> index 729f42b0a..bd12d0bc9 100644
> --- a/lib/i915/gem_engine_topology.c
> +++ b/lib/i915/gem_engine_topology.c
> @@ -488,6 +488,52 @@ int gem_engine_property_printf(int i915, const char *engine, const char *attr,
>  	return ret;
>  }
>  
> +/* Ensure fast hang detection */
> +void gem_engine_properties_configure(int fd, struct gem_engine_properties *params)
> +{
> +	int ret;
> +	struct gem_engine_properties write = *params;
> +
> +	ret = gem_engine_property_scanf(fd, write.engine->name,
> +					"heartbeat_interval_ms",
> +					"%d", &params->heartbeat_interval);
> +	igt_assert_eq(ret, 1);
> +
> +	ret = gem_engine_property_printf(fd, write.engine->name,
> +					 "heartbeat_interval_ms", "%d",
> +					 write.heartbeat_interval);
> +	igt_assert_lt(0, ret);
> +
> +	if (gem_scheduler_has_preemption(fd)) {
> +		ret = gem_engine_property_scanf(fd, write.engine->name,
> +						"preempt_timeout_ms",
> +						"%d", &params->preempt_timeout);
> +		igt_assert_eq(ret, 1);
> +
> +		ret = gem_engine_property_printf(fd, write.engine->name,
> +						 "preempt_timeout_ms", "%d",
> +						 write.preempt_timeout);
> +		igt_assert_lt(0, ret);
> +	}
> +}
> +
> +void gem_engine_properties_restore(int fd, const struct gem_engine_properties *saved)
> +{
> +	int ret;
> +
> +	ret = gem_engine_property_printf(fd, saved->engine->name,
> +					 "heartbeat_interval_ms", "%d",
> +					 saved->heartbeat_interval);
> +	igt_assert_lt(0, ret);
> +
> +	if (gem_scheduler_has_preemption(fd)) {
> +		ret = gem_engine_property_printf(fd, saved->engine->name,
> +						 "preempt_timeout_ms", "%d",
> +						 saved->preempt_timeout);
> +		igt_assert_lt(0, ret);
> +	}
> +}
> +
>  uint32_t gem_engine_mmio_base(int i915, const char *engine)
>  {
>  	unsigned int mmio = 0;
> diff --git a/lib/i915/gem_engine_topology.h b/lib/i915/gem_engine_topology.h
> index 4cfab560b..b413aa8ab 100644
> --- a/lib/i915/gem_engine_topology.h
> +++ b/lib/i915/gem_engine_topology.h
> @@ -115,6 +115,15 @@ struct intel_execution_engine2 gem_eb_flags_to_engine(unsigned int flags);
>  	     ((e__) = intel_get_current_physical_engine(&i__##e__)); \
>  	     intel_next_engine(&i__##e__))
>  
> +struct gem_engine_properties {
> +	const struct intel_execution_engine2 *engine;
> +	int preempt_timeout;
> +	int heartbeat_interval;
> +};
> +
> +void gem_engine_properties_configure(int fd, struct gem_engine_properties *params);
> +void gem_engine_properties_restore(int fd, const struct gem_engine_properties *saved);
> +
>  __attribute__((format(scanf, 4, 5)))
>  int gem_engine_property_scanf(int i915, const char *engine, const char *attr,
>  			      const char *fmt, ...);
> -- 
> 2.25.1
>