From ee9751f14928ab3fa8fee21a1a18cd9bd42a8d39 Mon Sep 17 00:00:00 2001
From: Kenny Ballou <kb@devnulllabs.io>
Date: Fri, 13 Jan 2023 23:39:07 -0700
Subject: compute usable number of cores for builds

Consider 1/4 of the CPU count as "usable" for Guix builds.

Signed-off-by: Kenny Ballou <kb@devnulllabs.io>
---
 Makefile | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

(limited to 'Makefile')

diff --git a/Makefile b/Makefile
index 9936d588..bf3f552e 100644
--- a/Makefile
+++ b/Makefile
@@ -5,6 +5,9 @@ HOSTS=h4x daeva owl baal yak koi bard
 SYSTEMS=$(patsubst %,systems/%,$(HOSTS))
 HOMES=$(patsubst %,homes/%,$(HOSTS))
 HOSTNAME=$(shell hostname)
+NPROC=$(shell nproc)
+CORES=$(guile (max 1 (floor (/ $(NPROC) 4))))
+
 
 .PHONY: current-system
 current-system: config/emacs/emacs.d/init.el homes/$(HOSTNAME) systems/$(HOSTNAME)
@@ -65,11 +68,11 @@ all-systems: $(SYSTEMS)
 all-homes: $(HOMES)
 
 $(HOMES):
-	guix time-machine -C $(CHANNEL_FILE) -- home build --cores=2 $@.scm
+	guix time-machine -C $(CHANNEL_FILE) -- home build --cores=$(CORES) $@.scm
 
 .PHONY: $(SYSTEMS)
 $(SYSTEMS):
-	guix time-machine -C $(CHANNEL_FILE) -- system build --cores=2 $@.scm
+	guix time-machine -C $(CHANNEL_FILE) -- system build --cores=$(CORES) $@.scm
 
 ## Private targets
 config/emacs/emacs.d/init.el config/emacs/emacs.d/early-init.el: config/emacs/emacs.d/emacs.org
-- 
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