Add support for CPU/RAM overcommit, disabling toolchains0.5.0

1 files changed, 26 insertions, 6 deletions

diff --git a/doc/manual.cli b/doc/manual.cli
index 1acf526..0178738 100644
--- a/doc/manual.cli
+++ b/doc/manual.cli
@@ -178,6 +178,24 @@ sudo kvm \
 
 \h1#config|Configuration|
 
+\h#config-cpu-ram|CPU and RAM|
+
+A Build OS instances divides available CPUs and RAM (minus 4G) into \i{slices}
+that are then \i{committed} to each toolchain. If you don't expect your
+toolchains 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:
+
+\
+buildos.cpu_overcommit=3/2
+\
+
+A Build OS machine with 8 CPUs (hardware threads) and three toolchains will
+assign 4 CPUs (\c{8 * 3/2 / 3}) to each slice.
+
+
 \h#config-storage|Storage|
 
 Build OS configures storage based on the labels assigned to disks and
@@ -324,12 +342,14 @@ for example, \c{buildos.toolchain_url.<name>} (values without the toolchain
 name use the toolchain name \c{default}). The toolchain name may not contain
 \c{-}.
 
-Each line in the checksums file is the output of the \c{shaNNNsum(1)} utility,
-that is, the SHANNN sum following by space, an asterisk (\c{*}) which signals
-the binary mode), and the relative file path. Blank lines and lines that start
-with \c{#} are ignored. The extension of the checksums file should be
-\c{.shaNNN} and the first entry should be for the \c{build2-toolchain} \c{tar}
-archive itself (used to derive the toolchain version). For example:
+In the checksums file blank lines and lines that start with \c{#} are ignored.
+If the first line is the special \c{disabled} value, then this toolchain is
+ignored. Otherwise, each line in the checksums file is the output of the
+\c{shaNNNsum(1)} utility, that is, the SHANNN sum following by space, an
+asterisk (\c{*}, which signals the binary mode), and the relative file path.
+The extension of the checksums file should be \c{.shaNNN} and the first line
+should be for the \c{build2-toolchain} \c{tar} archive itself (used to derive
+the toolchain version). For example:
 
 \
 # toolchain.sha256