Add ability to specify RAM for auxiliary machinesHEADmaster

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

1 files changed, 34 insertions, 10 deletions

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|