intel: use pwrite for batch

It's faster. Not only is the memcpy more efficiently performed in the
kernel (making up for the system call overhead), but by not using mmap
we remove the greater overhead of tracking the vma of every batch.

And it means we can read back from the batch buffer without incurring
the cost of a uncached read through the GTT.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 7 insertions, 7 deletions

diff --git a/src/mesa/drivers/dri/i965/brw_state_batch.c b/src/mesa/drivers/dri/i965/brw_state_batch.c
index 6d7b6a4..f363a92 100644
--- a/src/mesa/drivers/dri/i965/brw_state_batch.c
+++ b/src/mesa/drivers/dri/i965/brw_state_batch.c
@@ -48,7 +48,7 @@ GLboolean brw_cached_batch_struct( struct brw_context *brw,
    struct header *newheader = (struct header *)data;
 
    if (brw->emit_state_always) {
-      intel_batchbuffer_data(brw->intel.batch, data, sz, false);
+      intel_batchbuffer_data(&brw->intel, data, sz, false);
       return GL_TRUE;
    }
 
@@ -75,7 +75,7 @@ GLboolean brw_cached_batch_struct( struct brw_context *brw,
 
  emit:
    memcpy(item->header, newheader, sz);
-   intel_batchbuffer_data(brw->intel.batch, data, sz, false);
+   intel_batchbuffer_data(&brw->intel, data, sz, false);
    return GL_TRUE;
 }
 
@@ -118,10 +118,10 @@ brw_state_batch(struct brw_context *brw,
 		int alignment,
 		uint32_t *out_offset)
 {
-   struct intel_batchbuffer *batch = brw->intel.batch;
+   struct intel_batchbuffer *batch = &brw->intel.batch;
    uint32_t offset;
 
-   assert(size < batch->buf->size);
+   assert(size < batch->bo->size);
    offset = ROUND_DOWN_TO(batch->state_batch_offset - size, alignment);
 
    /* If allocating from the top would wrap below the batchbuffer, or
@@ -129,13 +129,13 @@ brw_state_batch(struct brw_context *brw,
     * space, then flush and try again.
     */
    if (batch->state_batch_offset < size ||
-       offset < batch->ptr - batch->map + batch->reserved_space) {
-      intel_batchbuffer_flush(batch);
+       offset < 4*batch->used + batch->reserved_space) {
+      intel_batchbuffer_flush(&brw->intel);
       offset = ROUND_DOWN_TO(batch->state_batch_offset - size, alignment);
    }
 
    batch->state_batch_offset = offset;
 
    *out_offset = offset;
-   return batch->map + offset;
+   return batch->map + (offset>>2);
 }