[Nix-dev] [PATCH 1/2] t/nix-patch

[Marc Weber]

nix num-cores.patch

Signed-off-by: Marc Weber <marco-oweber at gmx.de>
---
 pkgs/tools/package-management/nix/num-cores.patch |  101 +++++++++++++++++++++
 pkgs/tools/package-management/nix/unstable.nix    |    2 +
 2 files changed, 103 insertions(+), 0 deletions(-)
 create mode 100644 pkgs/tools/package-management/nix/num-cores.patch

diff --git a/pkgs/tools/package-management/nix/num-cores.patch b/pkgs/tools/package-management/nix/num-cores.patch
new file mode 100644
index 0000000..b6127af
--- /dev/null
+++ b/pkgs/tools/package-management/nix/num-cores.patch
@@ -0,0 +1,101 @@
+commit 0c86b116e3bc80dfac1a5e3939416c43c9c0d263
+Author: Marc Weber <marco-oweber at gmx.de>
+Date:   Tue Jun 8 02:33:58 2010 +0200
+
+    t/num_cores
+    
+    pass NUM_CORES to the builder
+    opt-out possible by
+    - setting NUM_CORES=1 in a a derivation.
+      This intentionally affects the $out hash so that you get a sane
+      system when passing NUM_CORES=1 if make install -j4 didn't install everything
+      with NUM_CORES > 1
+    - setting num_cores=1 in Nix config /nix/etc/nix/nix.conf
+    - passing NUM_CORES=1 to the nix-daemon instance
+    
+    passing NUM_CORES=`$coreutils/bin/nproc` to nix-daemon is the recommended way
+    to set NUM_CORES.
+    
+    Unless you use NUM_CORES aware builder scripts nothing should change.
+    NUM_CORES aware builder scripts will be available in a top-git branch soon.
+    
+    TODO: add documentation
+
+diff --git a/src/libmain/shared.cc b/src/libmain/shared.cc
+index 3fbec4b..fb02961 100644
+--- a/src/libmain/shared.cc
++++ b/src/libmain/shared.cc
+@@ -137,6 +137,19 @@ static void initAndRun(int argc, char * * argv)
+     maxBuildJobs = queryIntSetting("build-max-jobs", 1);
+     maxSilentTime = queryIntSetting("build-max-silent-time", 0);
+ 
++    /* initialise num_cores: if it was not set in config try getting value
++     * from environments. Value should have been set by nproc in the upstart
++     * job - I don't want to think about a portable way to get this value.
++     * In fact num_cores can change eg when you pull cores off or online ..
++     * */
++    num_cores = atoi(querySetting("num_cores", "-1").c_str());
++    if (num_cores == -1 && getenv("NUM_CORES")){
++      num_cores = atoi(getenv("NUM_CORES"));
++    }
++    // enusre num_cores >=1 && <= 500
++    if (num_cores > 500) num_cores = 500;
++    if (num_cores <= 0) num_cores = 1;
++
+     /* Catch SIGINT. */
+     struct sigaction act;
+     act.sa_handler = sigintHandler;
+diff --git a/src/libstore/build.cc b/src/libstore/build.cc
+index 4126406..7bdfa7d 100644
+--- a/src/libstore/build.cc
++++ b/src/libstore/build.cc
+@@ -1415,6 +1415,18 @@ void DerivationGoal::startBuilder()
+     foreach (StringPairs::iterator, i, drv.env)
+         env[i->first] = i->second;
+ 
++    /* if NUM_CORES was set by derivation it must be "1"
++     * override by global num_cores otherwise which is known to be an int > 0 and < 500
++     */
++    Environment::iterator num_cores_iter = env.find("NUM_CORES");
++    bool invalid_num_cores_value = false;
++    if( num_cores_iter == env.end()
++      || (invalid_num_cores_value = num_cores_iter->second.compare("1") != 0) ) {
++      if (invalid_num_cores_value)
++        trace("overriding invalid NUM_CORES value");
++      env["NUM_CORES"] = (format("%d") % num_cores).str();
++    }
++
+     /* Create a temporary directory where the build will take
+        place. */
+     tmpDir = createTempDir("", "nix-build-" + baseNameOf(drvPath), false, false);
+diff --git a/src/libstore/globals.cc b/src/libstore/globals.cc
+index cc0e44e..adfa0f1 100644
+--- a/src/libstore/globals.cc
++++ b/src/libstore/globals.cc
+@@ -25,6 +25,7 @@ unsigned int maxBuildJobs = 1;
+ bool readOnlyMode = false;
+ string thisSystem = "unset";
+ time_t maxSilentTime = 0;
++int num_cores = 0;
+ Paths substituters;
+ bool useBuildHook = true;
+ bool printBuildTrace = false;
+diff --git a/src/libstore/globals.hh b/src/libstore/globals.hh
+index d3388e3..a0fb358 100644
+--- a/src/libstore/globals.hh
++++ b/src/libstore/globals.hh
+@@ -67,6 +67,14 @@ extern string thisSystem;
+    infinity. */
+ extern time_t maxSilentTime;
+ 
++/* 0 = auto which means num_cores is set to the amount of cores the system has
++ * 1 = disable parallel builds which means pass NUM_CORES=1 to the build
++ *     scripts always
++ * n = pass this value to the builder
++ * You can set NUM_CORES=1 in a derivation to prevent a parallel builds
++*/
++extern int num_cores;
++
+ /* The substituters.  There are programs that can somehow realise a
+    store path without building, e.g., by downloading it or copying it
+    from a CD. */
diff --git a/pkgs/tools/package-management/nix/unstable.nix b/pkgs/tools/package-management/nix/unstable.nix
index 6c6cbbe..aa2c746 100644
--- a/pkgs/tools/package-management/nix/unstable.nix
+++ b/pkgs/tools/package-management/nix/unstable.nix
@@ -40,4 +40,6 @@ stdenv.mkDerivation rec {
     homepage = http://nixos.org/;
     license = "LGPLv2+";
   };
+
+  patches = [ ./num-cores.patch ];
 }
-- 
1.7.1