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Commit efdfd91f authored by Chris Wilson's avatar Chris Wilson
Browse files

drm/i915/cmdparser: Compare against the previous command descriptor 



On the blitter (and in test code), we see long sequences of repeated
commands, e.g. XY_PIXEL_BLT, XY_SCANLINE_BLT, or XY_SRC_COPY. For these,
we can skip the hashtable lookup by remembering the previous command
descriptor and doing a straightforward compare of the command header.
The corollary is that we need to do one extra comparison before lookup
up new commands.

v2: Less magic mask (ok, it is still magic, but now you cannot see!)

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20160818161718.27187-36-chris@chris-wilson.co.uk
parent d6a4ead7

drivers/gpu/drm/i915/i915_cmd_parser.c

+14 −7
Original line number Diff line number Diff line
@@ -90,6 +90,7 @@ 
#define STD_3D_OPCODE_SHIFT  (32 - 16)

#define STD_2D_OPCODE_SHIFT  (32 - 10)

#define STD_MFX_OPCODE_SHIFT (32 - 16)

#define MIN_OPCODE_SHIFT 16



#define CMD(op, opm, f, lm, fl, ...)				\

	{							\
@@ -350,6 +351,9 @@ static const struct drm_i915_cmd_descriptor hsw_blt_cmds[] = { 
	CMD(  MI_LOAD_SCAN_LINES_EXCL,          SMI,   !F,  0x3F,   R  ),

};



static const struct drm_i915_cmd_descriptor noop_desc =

	CMD(MI_NOOP, SMI, F, 1, S);



#undef CMD

#undef SMI

#undef S3D
@@ -893,11 +897,14 @@ find_cmd_in_table(struct intel_engine_cs *engine, 
static const struct drm_i915_cmd_descriptor*

find_cmd(struct intel_engine_cs *engine,

	 u32 cmd_header,

	 const struct drm_i915_cmd_descriptor *desc,

	 struct drm_i915_cmd_descriptor *default_desc)

{

	const struct drm_i915_cmd_descriptor *desc;

	u32 mask;



	if (((cmd_header ^ desc->cmd.value) & desc->cmd.mask) == 0)

		return desc;



	desc = find_cmd_in_table(engine, cmd_header);

	if (desc)

		return desc;
@@ -906,10 +913,10 @@ find_cmd(struct intel_engine_cs *engine, 
	if (!mask)

		return NULL;



	BUG_ON(!default_desc);

	default_desc->flags = CMD_DESC_SKIP;

	default_desc->cmd.value = cmd_header;

	default_desc->cmd.mask = ~0u << MIN_OPCODE_SHIFT;

	default_desc->length.mask = mask;



	default_desc->flags = CMD_DESC_SKIP;

	return default_desc;

}
@@ -1188,7 +1195,8 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine, 
			    bool is_master)

{

	u32 *cmd, *batch_end;

	struct drm_i915_cmd_descriptor default_desc = { 0 };

	struct drm_i915_cmd_descriptor default_desc = noop_desc;

	const struct drm_i915_cmd_descriptor *desc = &default_desc;

	bool oacontrol_set = false; /* OACONTROL tracking. See check_cmd() */

	bool needs_clflush_after = false;

	int ret = 0;
@@ -1208,13 +1216,12 @@ int intel_engine_cmd_parser(struct intel_engine_cs *engine, 
	 */

	batch_end = cmd + (batch_len / sizeof(*batch_end));

	while (cmd < batch_end) {

		const struct drm_i915_cmd_descriptor *desc;

		u32 length;



		if (*cmd == MI_BATCH_BUFFER_END)

			break;



		desc = find_cmd(engine, *cmd, &default_desc);

		desc = find_cmd(engine, *cmd, desc, &default_desc);

		if (!desc) {

			DRM_DEBUG_DRIVER("CMD: Unrecognized command: 0x%08X\n",

					 *cmd);