Add support for EEVDF scheduler

Changes enabled when EEVDF detected:

* Targeted preemption latency dropped
* Wake-up granularity dropped
* Minimal preemption granularity renamed to base slice
* Number of tasks to iterate in a single balance run from 64 to 8

set-cfs-zen-tweaks.sh

@@ -22,14 +22,16 @@ MIN_GRANULARITY_MS=0.4
 WAKEUP_GRANULARITY_MS=0.5
 MIGRATION_COST_MS=0.25
 BANDWIDTH_SIZE_MS=3
-NR_MIGRATE=64
+NR_MIGRATE_CFS=64
+NR_MIGRATE_EEVDF=8
+NR_MIGRATE="$NR_MIGRATE_CFS"
 
 echo "Targeted preemption latency for CPU-bound tasks: ${LATENCY_MS}ms"
 echo "Minimal preemption granularity for CPU-bound tasks: ${MIN_GRANULARITY_MS}ms"
 echo "Wake-up granularity: ${WAKEUP_GRANULARITY_MS}ms"
 echo "Task migration cost: ${MIGRATION_COST_MS}ms"
 echo "Amount of runtime to allocate from global to local pool: ${BANDWIDTH_SIZE_MS}ms"
-echo "Number of tasks to iterate in a single balance run: ${NR_MIGRATE}"
+echo "Number of tasks to iterate in a single balance run: CFS ${NR_MIGRATE_CFS} EEVDF ${NR_MIGRATE_EEVDF}"
 
 call_gawk() {
   printf '%s' "$(gawk 'BEGIN {print '"${1}"'}')"
@@ -39,14 +41,18 @@ NPROC="$(nproc)"
 # Linux uses this algorithm to multiply miliseconds
 MODIFIER="$( call_gawk "10 ** 6 * (1 + int(log(${NPROC}) / log(2)))" )"
 
+# Only CFS
 LATENCY_NS_FILE="/sys/kernel/debug/sched/latency_ns"
-MIN_GRANULARITY_NS_FILE="/sys/kernel/debug/sched/min_granularity_ns"
 WAKEUP_GRANULARITY_NS_FILE="/sys/kernel/debug/sched/wakeup_granularity_ns"
+MIN_GRANULARITY_NS_FILE="/sys/kernel/debug/sched/min_granularity_ns"
+# Both CFS and EEVDF
 MIGRATION_COST_NS_FILE="/sys/kernel/debug/sched/migration_cost_ns"
 BANDWIDTH_SIZE_US_FILE="/proc/sys/kernel/sched_cfs_bandwidth_slice_us"
 NR_MIGRATE_FILE="/sys/kernel/debug/sched/nr_migrate"
+# Only EEVDF
+BASE_SLICE_FILE="/sys/kernel/debug/sched/base_slice_ns"
 
-if [ ! -f "$LATENCY_NS_FILE" ]; then
+if [ ! -f "$NR_MIGRATE_FILE" ]; then
     echo "Detected kernel <5.13. Using legacy locations."
     LATENCY_NS_FILE="/proc/sys/kernel/sched_latency_ns"
     MIN_GRANULARITY_NS_FILE="/proc/sys/kernel/sched_min_granularity_ns"
@@ -55,9 +61,16 @@ if [ ! -f "$LATENCY_NS_FILE" ]; then
     NR_MIGRATE_FILE="/proc/sys/kernel/sched_nr_migrate"
 fi
 
-printf '%s' "$( call_gawk "int(${LATENCY_MS} * ${MODIFIER})" )" > "$LATENCY_NS_FILE"
+if [ -f "$LATENCY_NS_FILE" ]; then
+    printf '%s' "$( call_gawk "int(${LATENCY_MS} * ${MODIFIER})" )" > "$LATENCY_NS_FILE"
+    printf '%s' "$( call_gawk "int(${WAKEUP_GRANULARITY_MS} * ${MODIFIER})" )" > "$WAKEUP_GRANULARITY_NS_FILE"
+else
+    echo "Detected EEVDF scheduler"
+    NR_MIGRATE="$NR_MIGRATE_EEVDF"
+    MIN_GRANULARITY_NS_FILE="$BASE_SLICE_FILE"
+fi
+
 printf '%s' "$( call_gawk "int(${MIN_GRANULARITY_MS} * ${MODIFIER})" )" > "$MIN_GRANULARITY_NS_FILE"
-printf '%s' "$( call_gawk "int(${WAKEUP_GRANULARITY_MS} * ${MODIFIER})" )" > "$WAKEUP_GRANULARITY_NS_FILE"
 printf '%s' "$( call_gawk "int(${MIGRATION_COST_MS} * ${MODIFIER})" )" > "$MIGRATION_COST_NS_FILE"
 printf '%s' "$( call_gawk "int(${BANDWIDTH_SIZE_MS} * 1000)" )" > "$BANDWIDTH_SIZE_US_FILE"
 printf '%s' "$NR_MIGRATE" > "$NR_MIGRATE_FILE"