Migrate for latency

Signed-off-by: tytydraco <tylernij@gmail.com>

ktweak

@@ -1,6 +1,9 @@
 #!/usr/bin/env bash
 # Written by Draco (tytydraco @ GitHub)
 
+# The name of the current branch for logging purposes
+BRANCH="latency"
+
 # Maximum unsigned integer size in C
 UINT_MAX="4294967295"
 
@@ -8,7 +11,7 @@ UINT_MAX="4294967295"
 SCHED_PERIOD="$((1 * 1000 * 1000))"
 
 # How many tasks should we have at a maximum in one scheduling period
-SCHED_TASKS="8"
+SCHED_TASKS="10"
 
 write() {
 	# Bail out if file does not exist
@@ -40,13 +43,13 @@ grep -q android /proc/cmdline && ANDROID=true
 
 # Log the date and time for records sake
 echo "Time of execution: $(date)"
-echo "Branch: master"
+echo "Branch: $BRANCH"
 
 # Sync to data in the rare case a device crashes
 sync
 
 # Limit max perf event processing time to this much CPU usage
-write /proc/sys/kernel/perf_cpu_time_max_percent 5
+write /proc/sys/kernel/perf_cpu_time_max_percent 3
 
 # Group tasks for less stutter but less throughput
 write /proc/sys/kernel/sched_autogroup_enabled 1
@@ -73,7 +76,7 @@ write /proc/sys/kernel/sched_migration_cost_ns 5000000
 [[ "$ANDROID" == true ]] && write /proc/sys/kernel/sched_min_task_util_for_colocation 0
 
 # Improve real time latencies by reducing the scheduler migration time
-write /proc/sys/kernel/sched_nr_migrate 8
+write /proc/sys/kernel/sched_nr_migrate 4
 
 # Disable scheduler statistics to reduce overhead
 write /proc/sys/kernel/sched_schedstats 0
@@ -82,7 +85,7 @@ write /proc/sys/kernel/sched_schedstats 0
 write /proc/sys/kernel/printk_devkmsg off
 
 # Start non-blocking writeback later
-write /proc/sys/vm/dirty_background_ratio 10
+write /proc/sys/vm/dirty_background_ratio 3
 
 # Start blocking writeback later
 write /proc/sys/vm/dirty_ratio 30
@@ -119,8 +122,8 @@ then
 	# Consider scheduling tasks that are eager to run
 	write /sys/kernel/debug/sched_features NEXT_BUDDY
 
-	# Schedule tasks on their origin CPU if possible
-	write /sys/kernel/debug/sched_features TTWU_QUEUE
+	# Some sources report large latency spikes during large migrations
+	write /sys/kernel/debug/sched_features NO_TTWU_QUEUE
 fi
 
 [[ "$ANDROID" == true ]] && if [[ -d "/dev/stune/" ]]
@@ -154,12 +157,12 @@ done
 find /sys/devices/system/cpu/ -name schedutil -type d | while IFS= read -r governor
 do
 	# Consider changing frequencies once per scheduling period
-	write "$governor/up_rate_limit_us" "$((SCHED_PERIOD / 1000))"
-	write "$governor/down_rate_limit_us" "$((4 * SCHED_PERIOD / 1000))"
-	write "$governor/rate_limit_us" "$((SCHED_PERIOD / 1000))"
+	write "$governor/up_rate_limit_us" 0
+	write "$governor/down_rate_limit_us" 0
+	write "$governor/rate_limit_us" 0
 
 	# Jump to hispeed frequency at this load percentage
-	write "$governor/hispeed_load" 90
+	write "$governor/hispeed_load" 85
 	write "$governor/hispeed_freq" "$UINT_MAX"
 done
 
@@ -167,11 +170,11 @@ done
 find /sys/devices/system/cpu/ -name interactive -type d | while IFS= read -r governor
 do
 	# Consider changing frequencies once per scheduling period
-	write "$governor/timer_rate" "$((SCHED_PERIOD / 1000))"
-	write "$governor/min_sample_time" "$((SCHED_PERIOD / 1000))"
+	write "$governor/timer_rate" 0
+	write "$governor/min_sample_time" 0
 
 	# Jump to hispeed frequency at this load percentage
-	write "$governor/go_hispeed_load" 90
+	write "$governor/go_hispeed_load" 85
 	write "$governor/hispeed_freq" "$UINT_MAX"
 done
 
@@ -195,10 +198,10 @@ do
 	write "$queue/iostats" 0
 
 	# Reduce heuristic read-ahead in exchange for I/O latency
-	write "$queue/read_ahead_kb" 128
+	write "$queue/read_ahead_kb" 32
 
 	# Reduce the maximum number of I/O requests in exchange for latency
-	write "$queue/nr_requests" 64
+	write "$queue/nr_requests" 32
 done
 
 # Always return success, even if the last write fails