Add shared make jobserver support

This is a WIP to add a make job server into bitbake. This means the pool
of make tokens is central and shared by all tasks executed instead of the
current one job pool per task. Currently we can end up with many more
make subprocesses executing that is intended or optimal.

Implementation wise, make usually uses a pipe for this functionality. Here
we substitute a named pipe (fifo) and intercept the make commands, passing
in file descriptors to the central fifo. This assumes knowledge of make's
internal API, on the plus side it hasn't changed since 1999.

TODO:
  * Remove hardcoded /tmp/makefifo and use something in TMPDIR or similar
    (alongside the lock file?)
  * Remove hardcoded make threads number and set from PARALLEL_MAKE
  * If PARALELL_MAKE = "", don't set MAKEARGS (currently parallelism is
    set everywhere) (need to check for -j in make commandline)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

4 files changed, 57 insertions, 1 deletions

diff --git a/bitbake/bin/bitbake-worker b/bitbake/bin/bitbake-worker
index 3df783b2ad..5368b7903d 100755
--- a/bitbake/bin/bitbake-worker
+++ b/bitbake/bin/bitbake-worker
@@ -202,6 +202,7 @@ def fork_off_task(worker, cfg, data, workerdata, fn, task, taskname, appends, ta
             data.setVar("BUILDNAME", workerdata["buildname"])
             data.setVar("DATE", workerdata["date"])
             data.setVar("TIME", workerdata["time"])
+            data.setVar("BB_MAKEFIFO", workerdata["makefifo"])
             bb.parse.siggen.set_taskdata(workerdata["sigdata"])
             ret = 0
             try:
diff --git a/bitbake/lib/bb/runqueue.py b/bitbake/lib/bb/runqueue.py
index 7aca42224a..00d838fffb 100644
--- a/bitbake/lib/bb/runqueue.py
+++ b/bitbake/lib/bb/runqueue.py
@@ -924,6 +924,7 @@ class RunQueue:
             "buildname" : self.cfgData.getVar("BUILDNAME", True),
             "date" : self.cfgData.getVar("DATE", True),
             "time" : self.cfgData.getVar("TIME", True),
+            "makefifo" : self.cfgData.getVar("BB_MAKEFIFO", True),
         }
 
         worker.stdin.write("<cookerconfig>" + pickle.dumps(self.cooker.configuration) + "</cookerconfig>")
@@ -1050,6 +1051,27 @@ class RunQueue:
             cache[task] = iscurrent
         return iscurrent
 
+    def setup_make_fifo(self):
+        fifoname = "/tmp/makefifo"
+        self.cfgData.setVar("BB_MAKEFIFO", fifoname)
+        m = re.search(r'-j (\d+)', self.cfgData.getVar("PARALLEL_MAKE", True))
+        if m:
+            threads = int(m.group(1))
+        else:
+            threads = 1
+
+        if os.path.exists(fifoname):
+            os.remove(fifoname)
+        os.mkfifo(fifoname)
+ 
+        # Has to be open for read and writing
+        self.makereadfd = os.open(fifoname, os.O_RDONLY|os.O_NONBLOCK)
+        self.makewritefd = os.open(fifoname, os.O_WRONLY)
+        wfd = os.fdopen(self.makewritefd, 'w')
+
+        for x in range(0, threads):
+            wfd.write('+')
+
     def _execute_runqueue(self):
         """
         Run the tasks in a queue prepared by rqdata.prepare()
@@ -1071,6 +1093,8 @@ class RunQueue:
                     depgraph = self.cooker.buildDependTree(self, self.rqdata.taskData)
                     bb.event.fire(bb.event.DepTreeGenerated(depgraph), self.cooker.data)
 
+                self.setup_make_fifo()
+
         if self.state is runQueueSceneInit:
             dump = self.cooker.configuration.dump_signatures
             if dump:
diff --git a/meta/conf/bitbake.conf b/meta/conf/bitbake.conf
index 61d5bb5a89..41c5815110 100644
--- a/meta/conf/bitbake.conf
+++ b/meta/conf/bitbake.conf
@@ -424,7 +424,7 @@ EXTRA_IMAGEDEPENDS = ""
 # Toolchain info.
 ##################################################################
 
-PATH_prepend = "${COREBASE}/scripts:${STAGING_BINDIR_TOOLCHAIN}:${STAGING_BINDIR_CROSS}:${STAGING_DIR_NATIVE}${sbindir_native}:${STAGING_BINDIR_NATIVE}:${STAGING_DIR_NATIVE}${base_sbindir_native}:${STAGING_DIR_NATIVE}${base_bindir_native}:"
+PATH_prepend = "${COREBASE}/scripts/make-intercept:${COREBASE}/scripts:${STAGING_BINDIR_TOOLCHAIN}:${STAGING_BINDIR_CROSS}:${STAGING_DIR_NATIVE}${sbindir_native}:${STAGING_BINDIR_NATIVE}:${STAGING_DIR_NATIVE}${base_sbindir_native}:${STAGING_DIR_NATIVE}${base_bindir_native}:"
 export PATH
 
 ##################################################################
diff --git a/scripts/make-intercept/make b/scripts/make-intercept/make
new file mode 100755
index 0000000000..23cfb11b84
--- /dev/null
+++ b/scripts/make-intercept/make
@@ -0,0 +1,31 @@
+#!/usr/bin/env python
+import sys
+import os
+import subprocess
+
+if "BB_MAKEFIFO" in os.environ:
+    fifoname = os.environ["BB_MAKEFIFO"]
+
+    r = os.open(fifoname, os.O_RDONLY|os.O_NONBLOCK)
+    w = os.open(fifoname, os.O_WRONLY)
+    os.close(r)
+    r = os.open(fifoname, os.O_RDONLY)
+
+    seen = False
+    for i in sys.argv:
+        if "-j" in i:
+            seen = True
+    if seen:
+        os.environ["MAKEFLAGS"] = "-j --jobserver-fds=" + str(r) + "," + str(w)
+
+newpath = []
+origpath = os.environ["PATH"].split(":")
+for p in origpath:
+    if "make-intercept" in p:
+         continue
+    newpath.append(p)
+os.environ["PATH"] = ":".join(newpath)
+
+sys.argv[0] = "make"
+
+sys.exit(subprocess.call(sys.argv, shell=False))