| Submitter | Robert P. J. Day |
|---|---|
| Date | Jan. 9, 2013, 6:14 p.m. |
| Message ID | <alpine.DEB.2.02.1301091312270.14396@oneiric> |
| Download | mbox | patch |
| Permalink | /patch/42407/ |
| State | New |
| Headers | show |
Comments
On 01/09/2013 10:14 AM, Robert P. J. Day wrote: > > To be consistent with the Yocto Quick Start Guide, recommend that > parallelism represent twice the number of cores on a multi-core > machine. > > Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> > > --- > > diff --git a/meta/conf/local.conf.sample b/meta/conf/local.conf.sample > index 859eb93..46187ce 100644 > --- a/meta/conf/local.conf.sample > +++ b/meta/conf/local.conf.sample > @@ -24,9 +24,9 @@ > # > #PARALLEL_MAKE = "-j 4" > # > -# For a quad-core machine, BB_NUMBER_THREADS = "4", PARALLEL_MAKE = "-j 4" would > -# be appropriate for example. > - > +# If you have a multi-core machine, you would normally set both of these variables > +# to twice the number of cores. So for a quad-core machine, it would be appropriate > +# to set BB_NUMBER_THREADS = "8" and PARALLEL_MAKE = "-j 8". I think adding a note to ensure that hyperthreading is enabled would be appropriate, then number of threads = number of hyperthreaded cores (4 vs 8). Sau! > # > # Machine Selection > # >
Saul Wold <sgw-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> writes: >> #PARALLEL_MAKE = "-j 4" >> # >> -# For a quad-core machine, BB_NUMBER_THREADS = "4", PARALLEL_MAKE = "-j 4" would >> -# be appropriate for example. >> - >> +# If you have a multi-core machine, you would normally set both of these variables >> +# to twice the number of cores. So for a quad-core machine, it would be appropriate >> +# to set BB_NUMBER_THREADS = "8" and PARALLEL_MAKE = "-j 8". > > I think adding a note to ensure that hyperthreading is enabled would > be appropriate, then number of threads = number of hyperthreaded cores > (4 vs 8). what about a general | BB_NUMBER_THREADS ??= "${@os.sysconf(os.sysconf_names['SC_NPROCESSORS_ONLN'])}" in bitbake.conf? Or the sqrt() of it in in both PARALLEL_MAKE and BB_NUMBER_THREADS... Enrico
Patch
diff --git a/meta/conf/local.conf.sample b/meta/conf/local.conf.sample index 859eb93..46187ce 100644 --- a/meta/conf/local.conf.sample +++ b/meta/conf/local.conf.sample @@ -24,9 +24,9 @@ # #PARALLEL_MAKE = "-j 4" # -# For a quad-core machine, BB_NUMBER_THREADS = "4", PARALLEL_MAKE = "-j 4" would -# be appropriate for example. - +# If you have a multi-core machine, you would normally set both of these variables +# to twice the number of cores. So for a quad-core machine, it would be appropriate +# to set BB_NUMBER_THREADS = "8" and PARALLEL_MAKE = "-j 8". # # Machine Selection #
To be consistent with the Yocto Quick Start Guide, recommend that parallelism represent twice the number of cores on a multi-core machine. Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> ---