On Fri, Jul 27, 2018 at 5:46 PM, Marek Olšák <mar...@gmail.com> wrote:
> On Fri, Jul 27, 2018 at 5:08 PM, Eric Anholt <e...@anholt.net> wrote:
>> Marek Olšák <mar...@gmail.com> writes:
>>
>>> From: Marek Olšák <marek.ol...@amd.com>
>>>
>>> v2: need to do MAX{start+count} instead of MAX{count}
>>> added piglit tests
>>> ---
>>> src/gallium/auxiliary/util/u_vbuf.c | 199 ++++++++++++++++++++++++----
>>> 1 file changed, 175 insertions(+), 24 deletions(-)
>>>
>>> diff --git a/src/gallium/auxiliary/util/u_vbuf.c
>>> b/src/gallium/auxiliary/util/u_vbuf.c
>>> index 746ff1085ce..ca53e6218fd 100644
>>> --- a/src/gallium/auxiliary/util/u_vbuf.c
>>> +++ b/src/gallium/auxiliary/util/u_vbuf.c
>>> @@ -1124,20 +1124,45 @@ static void u_vbuf_set_driver_vertex_buffers(struct
>>> u_vbuf *mgr)
>>> unsigned start_slot, count;
>>>
>>> start_slot = ffs(mgr->dirty_real_vb_mask) - 1;
>>> count = util_last_bit(mgr->dirty_real_vb_mask >> start_slot);
>>>
>>> pipe->set_vertex_buffers(pipe, start_slot, count,
>>> mgr->real_vertex_buffer + start_slot);
>>> mgr->dirty_real_vb_mask = 0;
>>> }
>>>
>>> +static void
>>> +u_vbuf_split_indexed_multidraw(struct u_vbuf *mgr, struct pipe_draw_info
>>> *info,
>>> + unsigned *indirect_data, unsigned stride,
>>> + unsigned draw_count)
>>> +{
>>> + assert(info->index_size);
>>> + info->indirect = NULL;
>>> +
>>> + for (unsigned i = 0; i < draw_count; i++) {
>>> + unsigned offset = i * stride / 4;
>>> +
>>> + info->count = indirect_data[offset + 0];
>>> + info->instance_count = indirect_data[offset + 1];
>>> +
>>> + if (!info->count || !info->instance_count)
>>> + continue;
>>> +
>>> + info->start = indirect_data[offset + 2];
>>> + info->index_bias = indirect_data[offset + 3];
>>> + info->start_instance = indirect_data[offset + 4];
>>> +
>>> + u_vbuf_draw_vbo(mgr, info);
>>> + }
>>> +}
>>> +
>>> void u_vbuf_draw_vbo(struct u_vbuf *mgr, const struct pipe_draw_info *info)
>>> {
>>> struct pipe_context *pipe = mgr->pipe;
>>> int start_vertex;
>>> unsigned min_index;
>>> unsigned num_vertices;
>>> boolean unroll_indices = FALSE;
>>> const uint32_t used_vb_mask = mgr->ve->used_vb_mask;
>>> uint32_t user_vb_mask = mgr->user_vb_mask & used_vb_mask;
>>> const uint32_t incompatible_vb_mask =
>>> @@ -1153,47 +1178,172 @@ void u_vbuf_draw_vbo(struct u_vbuf *mgr, const
>>> struct pipe_draw_info *info)
>>> if (mgr->dirty_real_vb_mask & used_vb_mask) {
>>> u_vbuf_set_driver_vertex_buffers(mgr);
>>> }
>>>
>>> pipe->draw_vbo(pipe, info);
>>> return;
>>> }
>>>
>>> new_info = *info;
>>>
>>> - /* Fallback. We need to know all the parameters. */
>>> + /* Handle indirect (multi)draws. */
>>> if (new_info.indirect) {
>>> - struct pipe_transfer *transfer = NULL;
>>> - int *data;
>>> -
>>> - if (new_info.index_size) {
>>> - data = pipe_buffer_map_range(pipe, new_info.indirect->buffer,
>>> - new_info.indirect->offset, 20,
>>> - PIPE_TRANSFER_READ, &transfer);
>>> - new_info.index_bias = data[3];
>>> - new_info.start_instance = data[4];
>>> - }
>>> - else {
>>> - data = pipe_buffer_map_range(pipe, new_info.indirect->buffer,
>>> - new_info.indirect->offset, 16,
>>> - PIPE_TRANSFER_READ, &transfer);
>>> - new_info.start_instance = data[3];
>>> + const struct pipe_draw_indirect_info *indirect = new_info.indirect;
>>> + unsigned draw_count = 0;
>>> +
>>> + /* Get the number of draws. */
>>> + if (indirect->indirect_draw_count) {
>>> + pipe_buffer_read(pipe, indirect->indirect_draw_count,
>>> + indirect->indirect_draw_count_offset,
>>> + 4, &draw_count);
>>> + } else {
>>> + draw_count = indirect->draw_count;
>>> }
>>>
>>> - new_info.count = data[0];
>>> - new_info.instance_count = data[1];
>>> - new_info.start = data[2];
>>> - pipe_buffer_unmap(pipe, transfer);
>>> - new_info.indirect = NULL;
>>> -
>>> - if (!new_info.count)
>>> + if (!draw_count)
>>> return;
>>> +
>>> + unsigned data_size = (draw_count - 1) * indirect->stride +
>>> + (new_info.index_size ? 20 : 16);
>>> + unsigned *data = alloca(data_size);
>>
>> I continue to believe that alloca isn't something we should be using on
>> unbounded data_size like this. We should be returing GL_OUT_OF_MEMORY
>> when we fail, not segfaulting.
>>
>> We're already reading back the BOs, it's not like the allocation is a
>> performance concern at this point.
>
> radeonsi has optimizations where reading back BOs has no performance
> impact other than reading from uncached memory, i.e. no sync and no
> mmap overhead. In that case, malloc can make a difference. I agree
> that it may be a little harder to justify considering the other things
> that u_vbuf does.
Would it be OK with you if I pushed this patch as-is with alloca?
Marek
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