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drm/i915/guc: Increase size of CTB buffers

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With the introduction of non-blocking CTBs more than one CTB can be in
flight at a time. Increasing the size of the CTBs should reduce how
often software hits the case where no space is available in the CTB
buffer.

Cc: John Harrison <john.c.harrison@intel.com>
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Reviewed-by: Michal Wajdeczko <michal.wajdeczko@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210708162055.129996-4-matthew.brost@intel.com
This commit is contained in:
Matthew Brost 2021-07-08 09:20:51 -07:00 committed by John Harrison
parent dd9c0f3cbb
commit c26e289f1d
1 changed files with 8 additions and 3 deletions
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11
drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c
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@ -58,11 +58,16 @@ static inline struct drm_device *ct_to_drm(struct intel_guc_ct *ct)
* +--------+-----------------------------------------------+------+
*
* Size of each `CT Buffer`_ must be multiple of 4K.
* As we don't expect too many messages, for now use minimum sizes.
* We don't expect too many messages in flight at any time, unless we are
* using the GuC submission. In that case each request requires a minimum
* 2 dwords which gives us a maximum 256 queue'd requests. Hopefully this
* enough space to avoid backpressure on the driver. We increase the size
* of the receive buffer (relative to the send) to ensure a G2H response
* CTB has a landing spot.
*/
#define CTB_DESC_SIZE ALIGN(sizeof(struct guc_ct_buffer_desc), SZ_2K)
#define CTB_H2G_BUFFER_SIZE (SZ_4K)
#define CTB_G2H_BUFFER_SIZE (SZ_4K)
#define CTB_G2H_BUFFER_SIZE (4 * CTB_H2G_BUFFER_SIZE)
struct ct_request {
struct list_head link;
@ -643,7 +648,7 @@ static int ct_read(struct intel_guc_ct *ct, struct ct_incoming_msg **msg)
/* beware of buffer wrap case */
if (unlikely(available < 0))
available += size;
CT_DEBUG(ct, "available %d (%u:%u)\n", available, head, tail);
CT_DEBUG(ct, "available %d (%u:%u:%u)\n", available, head, tail, size);
GEM_BUG_ON(available < 0);
header = cmds[head];