diff options
-rw-r--r-- | documentation/ref-manual/ref-variables.xml | 37 |
1 files changed, 34 insertions, 3 deletions
diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml index c330fe04a1..ea5b9d8506 100644 --- a/documentation/ref-manual/ref-variables.xml +++ b/documentation/ref-manual/ref-variables.xml | |||
@@ -872,8 +872,26 @@ | |||
872 | The OpenEmbedded build system automatically configures | 872 | The OpenEmbedded build system automatically configures |
873 | this variable to be equal to the number of cores on the | 873 | this variable to be equal to the number of cores on the |
874 | build system. | 874 | build system. |
875 | To gain optimal parallelism, you should not have to | 875 | For example, a system with a dual core processor that |
876 | override this variable. | 876 | also uses hyper-threading causes the |
877 | <filename>BB_NUMBER_THREADS<filename> variable to default | ||
878 | to "4". | ||
879 | </para> | ||
880 | |||
881 | <para> | ||
882 | For single socket systems (i.e. one CPU), you should not | ||
883 | have to override this variable to gain optimal parallelism | ||
884 | during builds. | ||
885 | However, if you have very large systems that employ | ||
886 | multiple physical CPUs, you might want to make sure the | ||
887 | <filename>BB_NUMBER_THREADS</filename> variable is not | ||
888 | set higher than "20". | ||
889 | </para> | ||
890 | |||
891 | <para> | ||
892 | For more information on speeding up builds, see the | ||
893 | "<link linkend='speeding-up-the-build'>Speeding Up the Build</link>" | ||
894 | section. | ||
877 | </para> | 895 | </para> |
878 | </glossdef> | 896 | </glossdef> |
879 | </glossentry> | 897 | </glossentry> |
@@ -8499,7 +8517,7 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" | |||
8499 | <link linkend='ref-tasks-compile'><filename>do_compile</filename></link> | 8517 | <link linkend='ref-tasks-compile'><filename>do_compile</filename></link> |
8500 | task in order to specify parallel compilation on the local | 8518 | task in order to specify parallel compilation on the local |
8501 | build host. | 8519 | build host. |
8502 | This variable is usually in the form "-j <x>", | 8520 | This variable is usually in the form "-j <replaceable>x</replaceable>", |
8503 | where x represents the maximum number of parallel threads | 8521 | where x represents the maximum number of parallel threads |
8504 | <filename>make</filename> can run. | 8522 | <filename>make</filename> can run. |
8505 | </para> | 8523 | </para> |
@@ -8513,6 +8531,19 @@ recipes-graphics/xorg-font/font-alias_1.0.3.bb:PR = "${INC_PR}.3" | |||
8513 | the software being built has problems running its | 8531 | the software being built has problems running its |
8514 | <filename>make</filename> process in parallel. | 8532 | <filename>make</filename> process in parallel. |
8515 | </note> | 8533 | </note> |
8534 | For single socket systems (i.e. one CPU), you should not | ||
8535 | have to override this variable to gain optimal parallelism | ||
8536 | during builds. | ||
8537 | However, if you have very large systems that employ | ||
8538 | multiple physical CPUs, you might want to make sure the | ||
8539 | <filename>PARALLEL_MAKE</filename> variable is not | ||
8540 | set higher than "20". | ||
8541 | </para> | ||
8542 | |||
8543 | <para> | ||
8544 | For more information on speeding up builds, see the | ||
8545 | "<link linkend='speeding-up-the-build'>Speeding Up the Build</link>" | ||
8546 | section. | ||
8516 | </para> | 8547 | </para> |
8517 | </glossdef> | 8548 | </glossdef> |
8518 | </glossentry> | 8549 | </glossentry> |