diff options
Diffstat (limited to 'erts/doc/src/erl.xml')
| -rw-r--r-- | erts/doc/src/erl.xml | 97 |
1 files changed, 86 insertions, 11 deletions
diff --git a/erts/doc/src/erl.xml b/erts/doc/src/erl.xml index 528a2d95aa..27a23174d5 100644 --- a/erts/doc/src/erl.xml +++ b/erts/doc/src/erl.xml @@ -1,4 +1,4 @@ -<?xml version="1.0" encoding="latin1" ?> +<?xml version="1.0" encoding="utf-8" ?> <!DOCTYPE comref SYSTEM "comref.dtd"> <comref> @@ -792,6 +792,54 @@ SMP support enabled (see the <seealso marker="#smp">-smp</seealso> flag).</p> </item> + <tag><marker id="+SDcpu"><c><![CDATA[+SDcpu DirtyCPUSchedulers:DirtyCPUSchedulersOnline]]></c></marker></tag> + <item> + <p>Sets the number of dirty CPU scheduler threads to create and dirty + CPU scheduler threads to set online when threading support has been + enabled. The maximum for both values is 1024, and each value is further + limited by the settings for normal schedulers: the number of dirty CPU + scheduler threads created cannot exceed the number of normal scheduler + threads created, and the number of dirty CPU scheduler threads online + cannot exceed the number of normal scheduler threads online (see the + <seealso marker="#+S">+S</seealso> and <seealso marker="#+SP">+SP</seealso> + flags for more details). By default, the number of dirty CPU scheduler + threads created equals the number of normal scheduler threads created, + and the number of dirty CPU scheduler threads online equals the number + of normal scheduler threads online. <c>DirtyCPUSchedulers</c> may be + omitted if <c>:DirtyCPUSchedulersOnline</c> is not and vice versa. The + number of dirty CPU schedulers online can be changed at run time via + <seealso marker="erlang#system_flag_dirty_cpu_schedulers_online">erlang:system_flag(dirty_cpu_schedulers_online, DirtyCPUSchedulersOnline)</seealso>. + </p> + <p>This option is ignored if the emulator doesn't have threading support + enabled. Currently, <em>this option is experimental</em> and is supported only + if the emulator was configured and built with support for dirty schedulers + enabled (it's disabled by default). + </p> + </item> + <tag><marker id="+SDPcpu"><c><![CDATA[+SDPcpu DirtyCPUSchedulersPercentage:DirtyCPUSchedulersOnlinePercentage]]></c></marker></tag> + <item> + <p>Similar to <seealso marker="#+SDcpu">+SDcpu</seealso> but uses percentages to set the + number of dirty CPU scheduler threads to create and number of dirty CPU scheduler threads + to set online when threading support has been enabled. Specified values must be greater + than 0. For example, <c>+SDPcpu 50:25</c> sets the number of dirty CPU scheduler threads + to 50% of the logical processors configured and the number of dirty CPU scheduler threads + online to 25% of the logical processors available. <c>DirtyCPUSchedulersPercentage</c> may + be omitted if <c>:DirtyCPUSchedulersOnlinePercentage</c> is not and vice versa. The + number of dirty CPU schedulers online can be changed at run time via + <seealso marker="erlang#system_flag_dirty_cpu_schedulers_online">erlang:system_flag(dirty_cpu_schedulers_online, DirtyCPUSchedulersOnline)</seealso>. + </p> + <p>This option interacts with <seealso marker="#+SDcpu">+SDcpu</seealso> settings. + For example, on a system with 8 logical cores configured and 8 logical cores available, + the combination of the options <c>+SDcpu 4:4 +SDPcpu 50:25</c> (in either order) results + in 2 dirty CPU scheduler threads (50% of 4) and 1 dirty CPU scheduler thread online (25% of 4). + </p> + <p>This option is ignored if the emulator doesn't have threading support + enabled. Currently, <em>this option is experimental</em> and is supported only + if the emulator was configured and built with support for dirty schedulers + enabled (it's disabled by default). + </p> + </item> + <tag><marker id="+SDio"><c><![CDATA[+SDio IOSchedulers]]></c></marker></tag> <tag><c><![CDATA[+sFlag Value]]></c></tag> <item> <p>Scheduling specific flags.</p> @@ -941,6 +989,10 @@ when schedulers frequently run out of work. When disabled, the frequency with which schedulers run out of work will not be taken into account by the load balancing logic. + <br/> <c>+scl false</c> is similar to + <seealso marker="#+sub">+sub true</seealso> with the difference + that <c>+sub true</c> also will balance scheduler utilization + between schedulers. </p> </item> <tag><marker id="+sct"><c>+sct CpuTopology</c></marker></tag> @@ -1087,6 +1139,29 @@ documentation of the <seealso marker="#+sbt">+sbt</seealso> flag. </p> </item> + <tag><marker id="+sub"><c>+sub true|false</c></marker></tag> + <item> + <p>Enable or disable + <seealso marker="erts:erlang#statistics_scheduler_wall_time">scheduler + utilization</seealso> balancing of load. By default scheduler + utilization balancing is disabled and instead scheduler + compaction of load is enabled which will strive for a load + distribution which causes as many scheduler threads as possible + to be fully loaded (i.e., not run out of work). When scheduler + utilization balancing is enabled the system will instead try to + balance scheduler utilization between schedulers. That is, + strive for equal scheduler utilization on all schedulers. + <br/> <c>+sub true</c> is only supported on + systems where the runtime system detects and use a monotonically + increasing high resolution clock. On other systems, the runtime + system will fail to start. + <br/> <c>+sub true</c> implies + <seealso marker="#+scl">+scl false</seealso>. The difference + between <c>+sub true</c> and <c>+scl false</c> is that + <c>+scl false</c> will not try to balance the scheduler + utilization. + </p> + </item> <tag><marker id="+swct"><c>+sws very_eager|eager|medium|lazy|very_lazy</c></marker></tag> <item> <p> @@ -1126,18 +1201,18 @@ <tag><marker id="+spp"><c>+spp Bool</c></marker></tag> <item> <p>Set default scheduler hint for port parallelism. If set to - <c>true</c>, the VM will schedule port tasks when it by this can - improve the parallelism in the system. If set to <c>false</c>, - the VM will try to perform port tasks immediately and by this - improve latency at the expense of parallelism. If this - flag has not been passed, the default scheduler hint for port - parallelism is currently <c>false</c>. The default used can be - inspected in runtime by calling - <seealso marker="erlang#system_info_port_parallelism">erlang:system_info(port_parallelism)</seealso>. + <c>true</c>, the VM will schedule port tasks when doing so will + improve parallelism in the system. If set to <c>false</c>, the VM + will try to perform port tasks immediately, improving latency at the + expense of parallelism. If this flag has not been passed, the + default scheduler hint for port parallelism is currently + <c>false</c>. The default used can be inspected in runtime by + calling <seealso + marker="erlang#system_info_port_parallelism">erlang:system_info(port_parallelism)</seealso>. The default can be overriden on port creation by passing the <seealso marker="erlang#open_port_parallelism">parallelism</seealso> - option to - <seealso marker="erlang#open_port/2">open_port/2</seealso></p>. + option to <seealso + marker="erlang#open_port/2">open_port/2</seealso></p>. </item> <tag><marker id="sched_thread_stack_size"><c><![CDATA[+sss size]]></c></marker></tag> <item> |