Disable multicore detection

[GoogleCodeExporter]

Mozilla is doing so much more off-main-thread stuff that the G5 is now 
routinely being shown up by the single-core G4s due to 10.4's poor MP/MT 
performance. Turn this off for 10.4 in 24, but leave it on for 10.5. This 
probably requires wiring in Gestalt checks in a few places.

bruce:/home/spectre/src/bruce/mozilla-22.0/% grep -r _ONLN *
ipc/chromium/src/base/sys_info_posix.cc:#ifdef _SC_NPROCESSORS_ONLN
ipc/chromium/src/base/sys_info_posix.cc:  static long res = 
sysconf(_SC_NPROCESSORS_ONLN);
js/src/gdb/taskpool.py:        res = int(os.sysconf('SC_NPROCESSORS_ONLN'))
js/src/jsgc.cpp:        long n = sysconf(_SC_NPROCESSORS_ONLN);
js/src/tests/jstests.py:        res = int(os.sysconf('SC_NPROCESSORS_ONLN'))
media/libvpx/vp8/common/generic/systemdependent.c:#if 
defined(_SC_NPROCESSORS_ONLN)
media/libvpx/vp8/common/generic/systemdependent.c:    core_count = 
sysconf(_SC_NPROCESSORS_ONLN);
media/libvpx/vp8/common/generic/systemdependent.c:#elif defined(_SC_NPROC_ONLN)
media/libvpx/vp8/common/generic/systemdependent.c:    core_count = 
sysconf(_SC_NPROC_ONLN);
media/webrtc/trunk/tools/gyp/pylib/gyp/generator/scons.py:    if 
os.sysconf_names.has_key('SC_NPROCESSORS_ONLN'):
media/webrtc/trunk/tools/gyp/pylib/gyp/generator/scons.py:      return 
os.sysconf('SC_NPROCESSORS_ONLN')
memory/jemalloc/src/src/jemalloc.c:     result = sysconf(_SC_NPROCESSORS_ONLN);
memory/mozjemalloc/jemalloc.c:  return sysconf(_SC_NPROCESSORS_ONLN);
nsprpub/pr/src/misc/prsystem.c:    numCpus = sysconf( _SC_NPROC_ONLN );
grep: obj-ff-dbg/_leaktest/automation.py: No such file or directory
grep: obj-ff-dbg/_leaktest/leaktest.py: No such file or directory
python/psutil/psutil/_pslinux.py:    # SC_NPROCESSORS_ONLN seems to be the 
safer and it is also
python/psutil/psutil/_pslinux.py:        return 
os.sysconf("SC_NPROCESSORS_ONLN")
grep: toolkit/crashreporter/google-breakpad/autotools/compile: No such file or 
directory
widget/gonk/libui/EventHub.cpp:    mNumCpus = sysconf(_SC_NPROCESSORS_ONLN);

Original issue reported on code.google.com by classi...@floodgap.com on 1 Jul 2013 at 3:41

• Blocking: #193

[GoogleCodeExporter]

Original comment by classi...@floodgap.com on 1 Jul 2013 at 3:42

• Now blocking: #193

[GoogleCodeExporter]

Modified NSPR to report a single CPU on 10.4, and modified jsgc.cpp to use NSPR 
instead of its own detection code. This seems to restore performance 
significantly.

Original comment by classi...@floodgap.com on 3 Jul 2013 at 2:48

• Changed state: Started

[GoogleCodeExporter]

This issue appears to be independent of the multithreaded allocator (i.e., 
performance is bad if this is not enabled even in a jemalloc build).

Original comment by classi...@floodgap.com on 18 Jul 2013 at 2:29

• Changed title: Disable multicore detection on 10.4 [maybe 10.5 too?]

[GoogleCodeExporter]

This is borne out by tester reports. We will apply this to both for 22.1 final.

Original comment by classi...@floodgap.com on 26 Jul 2013 at 4:43

• Changed title: Disable multicore detection

[GoogleCodeExporter]

Original comment by classi...@floodgap.com on 11 Aug 2013 at 10:57

• Changed state: Verified