commit 386885514473261ebe39abd78d46a9f5f5187557
author Mel Henning <mhenning@darkrefraction.com> Mon Mar 31 15:09:28 2025 -0400
committer Marge Bot <emma+marge@anholt.net> Tue Apr 01 21:20:57 2025 +0000
tree 0ca469598099c3bd2e2a6d7030ec6a2b426eda43
parent 38d22121946094db21e97c5dae208d588cfc303c

nak/instr_sched: Barriers activate after 2 cycles

This mirrors the logic around line 365 of calc_instr_deps.rs

Reviewed-by: Faith Ekstrand <faith.ekstrand@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/33573>

src/nouveau/compiler/nak/opt_instr_sched_postpass.rs

diff --git a/src/nouveau/compiler/nak/opt_instr_sched_postpass.rs b/src/nouveau/compiler/nak/opt_instr_sched_postpass.rs
index 90054b9..209cf32 100644
--- a/src/nouveau/compiler/nak/opt_instr_sched_postpass.rs
+++ b/src/nouveau/compiler/nak/opt_instr_sched_postpass.rs
@@ -71,13 +71,17 @@
 
         uses.for_each_instr_dst_mut(instr, |i, u| {
             if let Some((w_ip, w_dst_idx)) = u.write {
-                let latency = sm.waw_latency(
+                let mut latency = sm.waw_latency(
                     &instr.op,
                     i,
                     !instr.pred.pred_ref.is_none(),
                     &instrs[w_ip].op,
                     w_dst_idx,
                 );
+                if sm.op_needs_scoreboard(&instr.op) {
+                    // Barriers take two cycles to become active
+                    latency = max(latency, 2);
+                }
                 g.add_edge(ip, w_ip, EdgeLabel { latency });
             }
 
@@ -98,8 +102,12 @@
         });
         uses.for_each_instr_src_mut(instr, |i, u| {
             if let Some((w_ip, w_dst_idx)) = u.write {
-                let latency =
+                let mut latency =
                     sm.war_latency(&instr.op, i, &instrs[w_ip].op, w_dst_idx);
+                if sm.op_needs_scoreboard(&instr.op) {
+                    // Barriers take two cycles to become active
+                    latency = max(latency, 2);
+                }
                 g.add_edge(ip, w_ip, EdgeLabel { latency });
             }
         });