[src/trunk]: src/sys/arch/amd64/conf Set AUDIO_BLK_MS=4 - unlikely to cause s...

[nia <nia%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/4f1f9167b5bd
branches:  trunk
changeset: 1006708:4f1f9167b5bd
user:      nia <nia%NetBSD.org@localhost>
date:      Fri Jan 24 18:58:46 2020 +0000

description:
Set AUDIO_BLK_MS=4 - unlikely to cause significant overhead on non-m68k.

Several of us have been setting this in /etc/sysctl.conf for months, to
get better performance from applications that require synced audio, etc.

It's also mentioned as a good value with low overhead on most archs here:
https://mail-index.netbsd.org/tech-kern/2019/12/07/msg025830.html

We could probably go lower, but this is low enough to make most/all
software run well, removing frame drops. It's also low enough to get
emulators/mednafen to stop complaining in the console.

diffstat:

 sys/arch/amd64/conf/GENERIC |  7 +++++--
 1 files changed, 5 insertions(+), 2 deletions(-)

diffs (28 lines):

diff -r 7cae811c8748 -r 4f1f9167b5bd sys/arch/amd64/conf/GENERIC
--- a/sys/arch/amd64/conf/GENERIC       Fri Jan 24 13:20:33 2020 +0000
+++ b/sys/arch/amd64/conf/GENERIC       Fri Jan 24 18:58:46 2020 +0000
@@ -1,4 +1,4 @@
-# $NetBSD: GENERIC,v 1.558 2020/01/20 18:38:19 thorpej Exp $
+# $NetBSD: GENERIC,v 1.559 2020/01/24 18:58:46 nia Exp $
 #
 # GENERIC machine description file
 #
@@ -22,7 +22,7 @@
 
 options        INCLUDE_CONFIG_FILE     # embed config file in kernel binary
 
-#ident         "GENERIC-$Revision: 1.558 $"
+#ident         "GENERIC-$Revision: 1.559 $"
 
 maxusers       64              # estimated number of users
 
@@ -55,6 +55,9 @@
 
 options        INSECURE        # disable kernel security levels - X needs this
 
+options                AUDIO_BLK_MS=4  # make software with low latency needs performant
+                               # no substantial CPU overhead on this platform
+
 options        RTC_OFFSET=0    # hardware clock is this many mins. west of GMT
 options        NTP             # NTP phase/frequency locked loop