Enable some performance tuning

These parameters increase the throughput on various (large-ish)
systems by 5-10% on the slight expense of higher power consumption.

Socket buffers are increases and the system is configured to be
less aggressive when scheduling processes from one processor to
another one which ensures that the cache remains "hot" for longer.

On a slower system (apu1d) no performance improvement or loss
could have been measured.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>

diff --git a/config/etc/sysctl.conf b/config/etc/sysctl.conf
index 46ab4e1d4ad9850958c0e665411aadc4529a50a7..7751bfd8a6bb18077620affd9636d7960b134f3e 100644 (file)
--- a/config/etc/sysctl.conf
+++ b/config/etc/sysctl.conf
@@ -24,7 +24,6 @@ net.ipv4.conf.all.accept_source_route = 0
 net.ipv4.conf.all.log_martians = 1
 
 kernel.printk = 1 4 1 7
 net.ipv4.conf.all.log_martians = 1
 
 kernel.printk = 1 4 1 7

-vm.swappiness=1

 vm.mmap_min_addr = 4096
 vm.min_free_kbytes = 8192
 
 vm.mmap_min_addr = 4096
 vm.min_free_kbytes = 8192
 


@@ -45,3 +44,45 @@ kernel.kptr_restrict = 2
 
 # Avoid kernel memory address exposures via dmesg.
 kernel.dmesg_restrict = 1
 
 # Avoid kernel memory address exposures via dmesg.
 kernel.dmesg_restrict = 1

+
+# Minimal preemption granularity for CPU-bound tasks:
+# (default: 1 msec#  (1 + ilog(ncpus)), units: nanoseconds)
+kernel.sched_min_granularity_ns = 10000000
+
+# If a workload mostly uses anonymous memory and it hits this limit, the entire
+# working set is buffered for I/O, and any more write buffering would require
+# swapping, so it's time to throttle writes until I/O can catch up.  Workloads
+# that mostly use file mappings may be able to use even higher values.
+#
+# The generator of dirty data starts writeback at this percentage (system default
+# is 20%)
+vm.dirty_ratio = 10
+
+# Start background writeback (via writeback threads) at this percentage (system
+# default is 10%)
+vm.dirty_background_ratio = 3
+
+# The swappiness parameter controls the tendency of the kernel to move
+# processes out of physical memory and onto the swap disk.
+# 0 tells the kernel to avoid swapping processes out of physical memory
+# for as long as possible
+# 100 tells the kernel to aggressively swap processes out of physical memory
+# and move them to swap cache
+vm.swappiness = 1
+
+# The total time the scheduler will consider a migrated process
+# "cache hot" and thus less likely to be re-migrated
+# (system default is 500000, i.e. 0.5 ms)
+kernel.sched_migration_cost_ns = 5000000
+
+# Increase kernel buffer size maximums
+net.ipv4.tcp_rmem = 4096 87380 16777216
+net.ipv4.tcp_wmem = 4096 16384 16777216
+net.ipv4.udp_mem = 3145728 4194304 16777216
+
+# Approximate time in us to busy loop waiting for packets on the device queue
+net.core.busy_read=50
+net.core.busy_poll=50
+
+# Enable TCP fast-open
+net.ipv4.tcp_fastopen = 3