[Beignet] [PATCH] runtime: fix potential curbe allocation issue.

[Song, Ruiling]

Two comments inline.
-----Original Message-----
From: Beignet [mailto:beignet-bounces at lists.freedesktop.org] On Behalf Of Zhigang Gong
Sent: Tuesday, July 01, 2014 12:55 PM
To: beignet at lists.freedesktop.org
Cc: Gong, Zhigang
Subject: [Beignet] [PATCH] runtime: fix potential curbe allocation issue.

According to spec, different platforms have different curbe allocation restrication. The previous code set the curbe allocated size to 480 statically which is not correct.

This patch change to always set the curbe entry num to 64 which is the maximum work group size. And set proper curbe allocation size according to the platform's hard limitation and a relatively reasonable kernel argument usage limitation.

Signed-off-by: Zhigang Gong <zhigang.gong at intel.com>

+#define MAX_KERNEL_ARG_SIZE (32 * 4 + 24 * 4 + 5 * 64) * 64 // 32 integer arguments, 24 uniform special register and 5 vector special register.
+


>>> Seem that MAX_KERNEL_ARG_SIZE you calculate from backend? If we add more payload register, we need also change here?
>>> I think we don't need this, it is OK we simply return the maximum curbe_size provided in hardware here.
>> The recommended function name is intel_gpgpu_get_max_curbe_size.

+LOCAL cl_int
+cl_get_max_curbe_size(uint32_t device_id) {
+  int max_curbe_size;
+  if (IS_BAYTRAIL_T(device_id) ||
+      IS_IVB_GT1(device_id))
+    max_curbe_size = 992;
+  else
+    max_curbe_size = 2016;
+
+  return (max_curbe_size*32) > MAX_KERNEL_ARG_SIZE ?
+         (MAX_KERNEL_ARG_SIZE / 32) : max_curbe_size; }
+


   /* curbe_size */
-  OUT_BATCH(gpgpu->batch, 480);
+  OUT_BATCH(gpgpu->batch, 
+ cl_get_max_curbe_size(gpgpu->drv->device_id));

>>> I think you can set curbe size here as "gpgpu->curb.size_cs_entry * gpgpu->curb.num_cs_entries", what do you think?