[PATCH i-g-t v2 6/8] lib/intel_multigpu: Add xe_multi_fork_foreach_gpu

[Piatkowski, Dominik Karol]

Hi Kamil,

> -----Original Message-----
> From: igt-dev <igt-dev-bounces at lists.freedesktop.org> On Behalf Of Kamil
> Konieczny
> Sent: Wednesday, January 24, 2024 9:42 PM
> To: igt-dev at lists.freedesktop.org
> Subject: [PATCH i-g-t v2 6/8] lib/intel_multigpu: Add
> xe_multi_fork_foreach_gpu
> 
> Create macro for testing Xe driver in multigpu scenarios with the help of few
> new multigpu functions. Also while at this, add documentation for public
> functions and use new helper in existing multi-gpu macro.
> 
> v2: corrected description (Kamil), rebased on corrected patches after Dominik
> review
> 
> Signed-off-by: Kamil Konieczny <kamil.konieczny at linux.intel.com>
> ---
>  lib/intel_multigpu.c | 94
> ++++++++++++++++++++++++++++++++++++++++++--
>  lib/intel_multigpu.h | 12 +++++-
>  2 files changed, 101 insertions(+), 5 deletions(-)
> 
> diff --git a/lib/intel_multigpu.c b/lib/intel_multigpu.c index
> 0e76d8aa3..e631ab0ed 100644
> --- a/lib/intel_multigpu.c
> +++ b/lib/intel_multigpu.c
> @@ -4,10 +4,18 @@
>   */
> 
>  #include "drmtest.h"
> +#include "i915/gem.h"
>  #include "igt_core.h"
>  #include "igt_device_scan.h"
>  #include "intel_multigpu.h"
> 
> +/**
> + * gem_multigpu_count_class:
> + * @class: chipset, e.g. DRIVER_XE or DRIVER_INTEL
> + *
> + * Function counts number of GPU cards with the help of opening all of them.
> + * Returns: number of GPUs cards found
> + */
>  int gem_multigpu_count_class(int class)  {
>  	int count = 0;
> @@ -18,7 +26,7 @@ int gem_multigpu_count_class(int class)
>  	return count;
>  }
> 
> -void gem_require_multigpu(int count)
> +static void skip_on_sigle_gpu(int count)

Nitpick: typo
I guess it should be named "skip_on_single_gpu".

>  {
>  	struct igt_devices_print_format fmt = {
>  		.type = IGT_PRINT_SIMPLE,
> @@ -26,9 +34,6 @@ void gem_require_multigpu(int count)
>  	};
>  	int devices;
> 
> -	if (igt_device_filter_count() >= count)
> -		return;
> -

As this conditional return was moved to gem_require_multigpu(), that function will work correctly. Although, calling skip_on_single_gpu() directly will always cause a skip due to always reachable igt_skip. I suggest changing igt_skip to igt_skip_on to avoid unexpected behavior in the future.

Additionally, skip_on_single_gpu can be refactored to not take any arguments, as we already get the number of gpus present in the system, and taking required count of gpus is not needed (it is always >1). The idea is to use igt_skip_on when devices < 2.

>  	igt_info("PCI devices available in the system:\n");
> 
>  	igt_devices_scan(true);
> @@ -37,3 +42,84 @@ void gem_require_multigpu(int count)
> 
>  	igt_skip("Test requires at least %d GPUs, %d available.\n", count,
> devices);  }
> +
> +/**
> + * gem_require_multigpu:
> + * @count: minimum number of GPUs required
> + *
> + * Function checks number of filtered GPU cards.
> + * On error skips and prints available GPUs found on PCI bus.
> + */
> +void gem_require_multigpu(int count)
> +{
> +	if (igt_device_filter_count() >= count)
> +		return;
> +
> +	skip_on_sigle_gpu(count);
> +}
> +
> +/**
> + * multigpu_aquire_view:
> + * @gpus_wanted: minimum number of GPUs required
> + * @chipset: chipset, e.g. DRIVER_XE or DRIVER_INTEL
> + *
> + * Function prepares filtered view for GPU cards with given chipset.
> + * On error skips and prints available GPUs found on PCI bus.
> + * Returns: number of GPUs found
> + */
> +int multigpu_aquire_view(int gpus_wanted, unsigned int chipset) {

Nitpick: typo
I guess it should be named "multigpu_acquire_view" (in function name and documentation).

Dominik Karol

> +	int gpu_count = drm_prepare_filtered_multigpu(chipset);
> +
> +	igt_assert(gpus_wanted > 1);
> +	if (gpu_count < gpus_wanted)
> +		skip_on_sigle_gpu(gpus_wanted);
> +
> +	return gpu_count;
> +}
> +
> +/**
> + * multigpu_open_another:
> + * @idx: index of GPU card, starting from 0
> + * @chipset: chipset, e.g. DRIVER_XE or DRIVER_INTEL
> + *
> + * Function opens GPU card with drm_open_driver_another(). For i915 it
> +checks
> + * if opened card is functional. Skips on errors.
> + * Returns: opened fd for @idx card
> + */
> +int multigpu_open_another(int idx, unsigned int chipset) {
> +	int fd;
> +
> +	igt_assert(idx >= 0);
> +	fd = drm_open_driver_another(idx, chipset);
> +
> +	igt_require(fd != -1);
> +	if (chipset == DRIVER_INTEL)
> +		igt_require_gem(fd);
> +
> +	return fd;
> +}
> +
> +/**
> + * multigpu_open_filtered_card:
> + * @idx: index of GPU card, starting from 0
> + * @chipset: chipset, e.g. DRIVER_XE or DRIVER_INTEL
> + *
> + * Function opens GPU card prepared with filtered view. It also checks
> +if
> + * opened card agrees with desired chipset or checks if opened card is
> + * functional. Skips on errors.
> + * Returns: opened fd for @idx card
> + */
> +int multigpu_open_filtered_card(int idx, unsigned int chipset) {
> +	int fd = drm_open_filtered_card(idx);
> +
> +	igt_require(fd != -1);
> +	if (chipset == DRIVER_XE)
> +		igt_require_xe(fd);
> +	else if (chipset == DRIVER_INTEL)
> +		igt_require_gem(fd);
> +
> +	return fd;
> +}
> diff --git a/lib/intel_multigpu.h b/lib/intel_multigpu.h index
> 0ebc73e4a..0032a619e 100644
> --- a/lib/intel_multigpu.h
> +++ b/lib/intel_multigpu.h
> @@ -12,6 +12,10 @@
>  void gem_require_multigpu(int count);
>  int gem_multigpu_count_class(int class);
> 
> +int multigpu_aquire_view(int min_gpus_wanted, unsigned int chipset);
> +int multigpu_open_another(int idx, unsigned int chipset); int
> +multigpu_open_filtered_card(int idx, unsigned int chipset);
> +
>  #define igt_foreach_gpu(fd__, id__) \
>  	for (int igt_unique(i) = 0, fd__; \
>  		(fd__ = __drm_open_driver_another(igt_unique(i)++, id__)) >=
> 0; \ @@ -19,8 +23,14 @@ int gem_multigpu_count_class(int class);
> 
>  #define igt_multi_fork_foreach_gpu(__fd, __id) \
>  	igt_multi_fork(igt_unique(__i), gem_multigpu_count_class(__id)) \
> -		for (int __fd = drm_open_driver_another(igt_unique(__i),
> __id); \
> +		for (int __fd = multigpu_open_another(igt_unique(__i), __id);
> \
>  			__fd >= 0; \
>  			close(__fd), __fd = -1) \
> 
> +#define xe_multi_fork_foreach_gpu(__fd, __gpu_index) \
> +	igt_multi_fork(__gpu_index, multigpu_aquire_view(2, DRIVER_XE)) \
> +		for (int __fd = multigpu_open_filtered_card(__gpu_index,
> DRIVER_XE); \
> +			__fd >= 0; \
> +			drm_close_driver(__fd), __fd = -1) \
> +
>  #endif /* __INTEL_MULTIGPU_H */
> --
> 2.42.0