Re: [igt-dev] [PATCH i-g-t 05/21] wsim/media-bench: i915 balancing

Tvrtko Ursulin
2019-05-13T12:41:47Z

On 10/05/2019 14:14, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2019-05-08 13:10:42)
>> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>>
>> Support i915 virtual engine from gem_wsim (-b i915) and media-bench.pl
>>
>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>> ---
>> + /*
>> + * Create and configure contexts.
>> + */
>> + for (i = 0; i < wrk->nr_ctxs; i += 2) {
>> + struct ctx *ctx = &wrk->ctx_list[i];
>> + uint32_t ctx_id, share_vm = 0;
>>
>> - wrk->ctx_list[w->context].id = arg.ctx_id;
>> + if (ctx->id)
>> + continue;
>>
>> - if (flags & GLOBAL_BALANCE) {
>> - wrk->ctx_list[w->context].static_vcs = context_vcs_rr;
>> - context_vcs_rr ^= 1;
>> - } else {
>> - wrk->ctx_list[w->context].static_vcs = ctx_vcs;
>> - ctx_vcs ^= 1;
>> - }
>> + if (flags & I915) {
>
> vm sharing shouldn't be a i915-balancer only option. For single jobs split
> across multiple contexts, I would expect they will want to share vm.

Could do but I wanted to limit the new features to new features. :)
Pencil in for later okay?

>> + struct drm_i915_gem_context_create_ext_setparam ext = {
>> + .base.name = I915_CONTEXT_CREATE_EXT_SETPARAM,
>> + .param.param = I915_CONTEXT_PARAM_VM,
>> + };
>> + struct drm_i915_gem_context_create_ext args = { };
>>
>> - if (wrk->prio) {
>> + /* Find existing context to share ppgtt with. */
>> + for (j = 0; j < wrk->nr_ctxs; j++) {
>> struct drm_i915_gem_context_param param = {
>> - .ctx_id = arg.ctx_id,
>> - .param = I915_CONTEXT_PARAM_PRIORITY,
>> - .value = wrk->prio,
>> + .param = I915_CONTEXT_PARAM_VM,
>> };
>> - gem_context_set_param(fd, &param);
>> +
>> + if (!wrk->ctx_list[j].id)
>> + continue;
>> +
>> + param.ctx_id = wrk->ctx_list[j].id;
>> +
>> + gem_context_get_param(fd, &param);
>> + igt_assert(param.value);
>> +
>> + share_vm = param.value;
>> +
>> + ext.param.value = share_vm;
>> + args.flags =
>> + I915_CONTEXT_CREATE_FLAGS_USE_EXTENSIONS;
>> + args.extensions = to_user_pointer(&ext);
>> + break;
>> }
>> +
>> + if (!ctx->targets_instance)
>> + args.flags |=
>> + I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE;
>> +
>> + drmIoctl(fd, DRM_IOCTL_I915_GEM_CONTEXT_CREATE_EXT,
>> + &args);
>> +
>> + ctx_id = args.ctx_id;
>> + } else {
>> + struct drm_i915_gem_context_create args = {};
>> +
>> + drmIoctl(fd, DRM_IOCTL_I915_GEM_CONTEXT_CREATE, &args);
>> + ctx_id = args.ctx_id;
>> + }
>> +
>> + igt_assert(ctx_id);
>> + ctx->id = ctx_id;
>> +
>> + if (flags & GLOBAL_BALANCE) {
>> + ctx->static_vcs = context_vcs_rr;
>> + context_vcs_rr ^= 1;
>> + } else {
>> + ctx->static_vcs = ctx_vcs;
>> + ctx_vcs ^= 1;
>> + }
>> +
>> + __ctx_set_prio(ctx_id, wrk->prio);
>> +
>> + /*
>> + * Do we need a separate context to satisfy this workloads which
>> + * both want to target specific engines and be balanced by i915?
>> + */
>> + if ((flags & I915) && ctx->wants_balance &&
>> + ctx->targets_instance) {
>> + struct drm_i915_gem_context_create_ext_setparam ext = {
>> + .base.name = I915_CONTEXT_CREATE_EXT_SETPARAM,
>> + .param.param = I915_CONTEXT_PARAM_VM,
>> + .param.value = share_vm,
>> + };
>> + struct drm_i915_gem_context_create_ext args = {
>> + .extensions = to_user_pointer(&ext),
>> + .flags =
>> + I915_CONTEXT_CREATE_FLAGS_USE_EXTENSIONS |
>> + I915_CONTEXT_CREATE_FLAGS_SINGLE_TIMELINE,
>> + };
>> +
>> + igt_assert(share_vm);
>> +
>> + drmIoctl(fd, DRM_IOCTL_I915_GEM_CONTEXT_CREATE_EXT,
>> + &args);
>> +
>> + igt_assert(args.ctx_id);
>> + ctx_id = args.ctx_id;
>> + wrk->ctx_list[i + 1].id = args.ctx_id;
>> +
>> + __ctx_set_prio(ctx_id, wrk->prio);
>> + }
>> +
>> + if (ctx->wants_balance) {
>> + I915_DEFINE_CONTEXT_ENGINES_LOAD_BALANCE(load_balance, 2) = {
>> + .base.name = I915_CONTEXT_ENGINES_EXT_LOAD_BALANCE,
>> + .num_siblings = 2,
>> + .engines = {
>> + { .engine_class = I915_ENGINE_CLASS_VIDEO,
>> + .engine_instance = 0 },
>> + { .engine_class = I915_ENGINE_CLASS_VIDEO,
>> + .engine_instance = 1 },
>> + },
>> + };
>> + I915_DEFINE_CONTEXT_PARAM_ENGINES(set_engines, 3) = {
>> + .extensions = to_user_pointer(&load_balance),
>> + .engines = {
>> + { .engine_class = I915_ENGINE_CLASS_INVALID,
>> + .engine_instance = I915_ENGINE_CLASS_INVALID_NONE },
>> + { .engine_class = I915_ENGINE_CLASS_VIDEO,
>> + .engine_instance = 0 },
>> + { .engine_class = I915_ENGINE_CLASS_VIDEO,
>> + .engine_instance = 1 },
>> + },
>> + };
>> +
>> + struct drm_i915_gem_context_param param = {
>> + .ctx_id = ctx_id,
>> + .param = I915_CONTEXT_PARAM_ENGINES,
>> + .size = sizeof(set_engines),
>> + .value = to_user_pointer(&set_engines),
>> + };
>> +
>> + gem_context_set_param(fd, &param);
>> }
>
> if (share_vm)
> gem_vm_destroy(share_vm);
>
> Just to drop the local handle as the context has acquired its own
> reference.

Well spotted!

> Other than that, it does what it sets out to do: create a context with
> choice of engines and load balancing amongst them.
>
> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

Thanks,

Tvrtko