From 8b7f8b56f11145c1be5188113cbcdbea27e99525 Mon Sep 17 00:00:00 2001 From: Peter Simons Date: Wed, 23 Jun 2010 14:34:08 +0000 Subject: Added support for passing an (impure) NIX_BUILD_CORES variable to build expressions. This patch adds the configuration file variable "build-cores" and the command line argument "--cores". These settings specify the number of CPU cores to utilize for parallel building within a job, i.e. by passing an appropriate "-j" flag to GNU Make. The default value is 1, which means that parallel building is *disabled*. If the number of build cores is specified as 0 (synonymously: "guess" or "auto"), then the actual value is supposed to be auto-detected by builders at run-time, i.e by calling the nproc(1) utility from coreutils. The environment variable $NIX_BUILD_CORES is available to builders, but the contents of that variable does *not* influence the hash that goes into the $out store path, i.e. the number of build cores to be utilized can be changed at will without requiring any re-builds. --- src/libstore/globals.hh | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'src/libstore/globals.hh') diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh index d3388e309c1b..a74a741d677e 100644 --- a/src/libstore/globals.hh +++ b/src/libstore/globals.hh @@ -55,6 +55,11 @@ extern Verbosity buildVerbosity; /* Maximum number of parallel build jobs. 0 means unlimited. */ extern unsigned int maxBuildJobs; +/* Number of CPU cores to utilize in parallel within a build, i.e. by passing + this number to Make via '-j'. 0 means that the number of actual CPU cores on + the local host ought to be auto-detected. */ +extern unsigned int buildCores; + /* Read-only mode. Don't copy stuff to the store, don't change the database. */ extern bool readOnlyMode; -- cgit 1.4.1