Add ability to specify RAM for auxiliary machines

Also drop support for RAM overcommit (unused and likely a bad idea).

2 files changed, 59 insertions, 26 deletions

diff --git a/buildos b/buildos
index 96cf209..dc4cd55 100755
--- a/buildos
+++ b/buildos
@@ -262,14 +262,19 @@ fi
 
 cpu_total="$(lscpu | sed -n -re 's/^CPU\(s\): *([0-9]+)$/\1/p')"
 
+# RAM reserved to the host.
+#
 if [ -z "$ram_reserved" ]; then
   ram_reserved=4
 fi
 ram_reserved=$(($ram_reserved * 1024 * 1024))
 
-if [ -z "$ram_overcommit" ]; then
-  ram_overcommit=1
+# RAM reserved for auxiliary machines.
+#
+if [ -z "$ram_auxiliary" ]; then
+  ram_auxiliary=0
 fi
+ram_auxiliary=$(($ram_auxiliary * 1024 * 1024))
 
 if [ -z "$cpu_reserved" ]; then
   cpu_reserved=0
@@ -279,11 +284,13 @@ if [ -z "$cpu_overcommit" ]; then
   cpu_overcommit=1
 fi
 
-ram_slice=$(($ram_total - $ram_reserved))
+ram_build_slice=$(($ram_total - $ram_reserved - $ram_auxiliary))
+ram_auxil_slice=$ram_auxiliary
 cpu_slice=$(($cpu_total - $cpu_reserved))
 
 if [ "$instances" -gt 1 ]; then
-  ram_slice=$(($ram_slice * $ram_overcommit / $instances))
+  ram_build_slice=$(($ram_build_slice / $instances))
+  ram_auxil_slice=$(($ram_auxil_slice / $instances))
   cpu_slice=$(($cpu_slice * $cpu_overcommit / $instances))
 
   if [ "$cpu_slice" -eq 0 ]; then
@@ -295,23 +302,24 @@ fi
 #
 function print ()
 {
-  echo "cpu_total:      $cpu_total"
-  echo "cpu_reserved:   $cpu_reserved"
-  echo "cpu_overcommit: $cpu_overcommit"
-  echo "cpu_slice:      $cpu_slice"
+  echo "cpu_total:       $cpu_total"
+  echo "cpu_reserved:    $cpu_reserved"
+  echo "cpu_overcommit:  $cpu_overcommit"
+  echo "cpu_slice:       $cpu_slice"
   if [ -n "$cpu_affinity" ]; then
-    echo "cpu_affinity:   $cpu_affinity"
+    echo "cpu_affinity:    $cpu_affinity"
   fi
   echo
 
-  echo "ram_total:      $ram_total KB"
-  echo "ram_reserved:   $ram_reserved KB"
-  echo "ram_overcommit: $ram_overcommit"
-  echo "ram_slice:      $ram_slice KB"
+  echo "ram_total:       $ram_total KiB"
+  echo "ram_reserved:    $ram_reserved KiB"
+  echo "ram_auxiliary:   $ram_auxiliary KiB"
+  echo "ram_build_slice: $ram_build_slice KiB"
+  echo "ram_auxil_slice: $ram_auxil_slice KiB"
   echo
 
-  echo "buildid:        $buildid"
-  echo "buildid_url:    $buildid_url"
+  echo "buildid:         $buildid"
+  echo "buildid_url:     $buildid_url"
   echo
 
   local n i tn tp tu tt
@@ -936,7 +944,8 @@ function bbot_start () # <toolchain-name> <toolchain-index>
     sed -i -r \
 	-e "s#%I#$tn/%I#g" \
 	-e "s/^(Environment=CPU)=.*/\1=$cpu_slice/" \
-	-e "s/^(Environment=RAM)=.*/\1=$ram_slice/" \
+	-e "s/^(Environment=RAM_BUILD)=.*/\1=$ram_build_slice/" \
+	-e "s/^(Environment=RAM_AUXIL)=.*/\1=$ram_auxil_slice/" \
 	-e "s/^(Environment=BRIDGE)=.*/\1=$tb/" \
 	-e "s#^(Environment=AUTH_KEY)=.*#\1=/state/etc/host-key.pem#" \
 	-e "s/^(Environment=INTERACTIVE)=.*/\1=$ta/" \
diff --git a/doc/manual.cli b/doc/manual.cli
index a994e9f..2852064 100644
--- a/doc/manual.cli
+++ b/doc/manual.cli
@@ -181,23 +181,47 @@ sudo kvm \
 
 A Build OS instances divides available CPUs and RAM (minus reserved, see
 below) into \i{slices} that are then \i{committed} to each instance of each
-toolchain. If you don't expect your builds to utilize these resources at the
-same time, then it may make sense to overcommit them to improve utilization.
-The respective overcommit values can be specified as ratios with the
-\c{buildos.cpu_overcommit} and \c{buildos.ram_overcommit} kernel command
-line parameters. For example, given the following CPU overcommit:
+toolchain. In case of CPU it normally makes sense to overcommit this resource
+in order to improve utilization. This can be achieved by specifying the
+overcommit values as a ratio with \c{buildos.cpu_overcommit}. For example,
+given the following CPU overcommit:
 
 \
 buildos.cpu_overcommit=3/2
 \
 
-A Build OS machine with 8 CPUs (hardware threads) and three toolchains will
+A Build OS machine with 8 CPUs (hardware threads) and three instances will
 assign 4 CPUs (\c{8 * 3/2 / 3}) to each slice.
 
-It is also possible to reserve a number of CPUs and an amount of RAM to
-Build OS with the \c{buildos.cpu_reserved} and \c{buildos.ram_reserved}
-(in GB) kernel command line parameters. If unspecified, 4GB of RAM is
-reserved by default.
+It is also possible to specify CPU affinity with \c{buildos.cpu_affinity}.
+For example, specifying:
+
+\
+buildos.cpu_affinity=2-9
+\
+
+Will restrict the instances to only running on CPUs 2-9.
+
+It is possible to reserve a number of CPUs and an amount of RAM to Build OS
+with the \c{buildos.cpu_reserved} and \c{buildos.ram_reserved} (in GiB) kernel
+command line parameters. If unspecified, 4GiB of RAM is reserved by default.
+
+An amount of RAM can be reserved for auxiliary machines with
+\c{buildos.ram_auxiliary}. This amount will also be divided into slices and
+committed to each instance.
+
+Finally, if the total available RAM cannot be auto-detected, it can be
+specified manually with \c{buildos.ram_total}. Here is a complete example of
+specifying all the possible RAM values:
+
+\
+buildos.ram_total=64
+buildos.ram_reserved=4
+buildos.ram_auxiliary=12
+\
+
+Assuming three instances, the configuration will assign 16GiB of build and
+4GiB of auxiliary RAM to each instance and keep 4GiB reserved to Build OS.
 
 
 \h#config-storage|Storage|