€•€9Œsphinx.addnodes”Œdocument”“”)”}”(Œ rawsource”Œ”Œchildren”]”(Œ translations”Œ LanguagesNode”“”)”}”(hhh]”(hŒ pending_xref”“”)”}”(hhh]”Œdocutils.nodes”ŒText”“”ŒChinese (Simplified)”…””}”Œparent”hsbaŒ attributes”}”(Œids”]”Œclasses”]”Œnames”]”Œdupnames”]”Œbackrefs”]”Œ refdomain”Œstd”Œreftype”Œdoc”Œ reftarget”Œ+/translations/zh_CN/virt/guest-halt-polling”Œmodname”NŒ classname”NŒ refexplicit”ˆuŒtagname”hhh ubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ+/translations/zh_TW/virt/guest-halt-polling”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ+/translations/it_IT/virt/guest-halt-polling”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ+/translations/ja_JP/virt/guest-halt-polling”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ+/translations/ko_KR/virt/guest-halt-polling”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ+/translations/sp_SP/virt/guest-halt-polling”Œmodname”NŒ classname”NŒ refexplicit”ˆuh1hhh ubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h hhŒ _document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒGuest halt polling”h]”hŒGuest halt polling”…””}”(hh¨hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh£hžhhŸŒE/var/lib/git/docbuild/linux/Documentation/virt/guest-halt-polling.rst”h KubhŒ paragraph”“”)”}”(hŒ†The cpuidle_haltpoll driver, with the haltpoll governor, allows the guest vcpus to poll for a specified amount of time before halting.”h]”hŒ†The cpuidle_haltpoll driver, with the haltpoll governor, allows the guest vcpus to poll for a specified amount of time before halting.”…””}”(hh¹hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¸)”}”(hŒ:This provides the following benefits to host side polling:”h]”hŒ:This provides the following benefits to host side polling:”…””}”(hhÇhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K hh£hžhubhŒ block_quote”“”)”}”(hŒÚ1) The POLL flag is set while polling is performed, which allows a remote vCPU to avoid sending an IPI (and the associated cost of handling the IPI) when performing a wakeup. 2) The VM-exit cost can be avoided. ”h]”hŒenumerated_list”“”)”}”(hhh]”(hŒ list_item”“”)”}”(hŒ¬The POLL flag is set while polling is performed, which allows a remote vCPU to avoid sending an IPI (and the associated cost of handling the IPI) when performing a wakeup. ”h]”h¸)”}”(hŒ«The POLL flag is set while polling is performed, which allows a remote vCPU to avoid sending an IPI (and the associated cost of handling the IPI) when performing a wakeup.”h]”hŒ«The POLL flag is set while polling is performed, which allows a remote vCPU to avoid sending an IPI (and the associated cost of handling the IPI) when performing a wakeup.”…””}”(hhæhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K hhâubah}”(h]”h ]”h"]”h$]”h&]”uh1hàhhÝubhá)”}”(hŒ!The VM-exit cost can be avoided. ”h]”h¸)”}”(hŒ The VM-exit cost can be avoided.”h]”hŒ The VM-exit cost can be avoided.”…””}”(hhþhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khhúubah}”(h]”h ]”h"]”h$]”h&]”uh1hàhhÝubeh}”(h]”h ]”h"]”h$]”h&]”Œenumtype”Œarabic”Œprefix”hŒsuffix”Œ)”uh1hÛhh×ubah}”(h]”h ]”h"]”h$]”h&]”uh1hÕhŸh¶h K hh£hžhubh¸)”}”(hŒkThe downside of guest side polling is that polling is performed even with other runnable tasks in the host.”h]”hŒkThe downside of guest side polling is that polling is performed even with other runnable tasks in the host.”…””}”(hj#hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¸)”}”(hŒ©The basic logic as follows: A global value, guest_halt_poll_ns, is configured by the user, indicating the maximum amount of time polling is allowed. This value is fixed.”h]”hŒ©The basic logic as follows: A global value, guest_halt_poll_ns, is configured by the user, indicating the maximum amount of time polling is allowed. This value is fixed.”…””}”(hj1hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¸)”}”(hŒšEach vcpu has an adjustable guest_halt_poll_ns ("per-cpu guest_halt_poll_ns"), which is adjusted by the algorithm in response to events (explained below).”h]”hŒžEach vcpu has an adjustable guest_halt_poll_ns (“per-cpu guest_halt_poll_nsâ€), which is adjusted by the algorithm in response to events (explained below).”…””}”(hj?hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¢)”}”(hhh]”(h§)”}”(hŒModule Parameters”h]”hŒModule Parameters”…””}”(hjPhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjMhžhhŸh¶h Kubh¸)”}”(hŒ6The haltpoll governor has 5 tunable module parameters:”h]”hŒ6The haltpoll governor has 5 tunable module parameters:”…””}”(hj^hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KhjMhžhubhÜ)”}”(hhh]”há)”}”(hŒguest_halt_poll_ns: ”h]”h¸)”}”(hŒguest_halt_poll_ns:”h]”hŒguest_halt_poll_ns:”…””}”(hjshžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K!hjoubah}”(h]”h ]”h"]”h$]”h&]”uh1hàhjlhžhhŸh¶h Nubah}”(h]”h ]”h"]”h$]”h&]”jjjhjjuh1hÛhjMhžhhŸh¶h K!ubh¸)”}”(hŒQMaximum amount of time, in nanoseconds, that polling is performed before halting.”h]”hŒQMaximum amount of time, in nanoseconds, that polling is performed before halting.”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K#hjMhžhubh¸)”}”(hŒDefault: 200000”h]”hŒDefault: 200000”…””}”(hj›hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K&hjMhžhubhÜ)”}”(hhh]”há)”}”(hŒguest_halt_poll_shrink: ”h]”h¸)”}”(hŒguest_halt_poll_shrink:”h]”hŒguest_halt_poll_shrink:”…””}”(hj°hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K(hj¬ubah}”(h]”h ]”h"]”h$]”h&]”uh1hàhj©hžhhŸh¶h Nubah}”(h]”h ]”h"]”h$]”h&]”jjjhjjŒstart”Kuh1hÛhjMhžhhŸh¶h K(ubh¸)”}”(hŒwDivision factor used to shrink per-cpu guest_halt_poll_ns when wakeup event occurs after the global guest_halt_poll_ns.”h]”hŒwDivision factor used to shrink per-cpu guest_halt_poll_ns when wakeup event occurs after the global guest_halt_poll_ns.”…””}”(hjËhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K*hjMhžhubh¸)”}”(hŒ Default: 2”h]”hŒ Default: 2”…””}”(hjÙhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K-hjMhžhubhÜ)”}”(hhh]”há)”}”(hŒguest_halt_poll_grow: ”h]”h¸)”}”(hŒguest_halt_poll_grow:”h]”hŒguest_halt_poll_grow:”…””}”(hjîhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K/hjêubah}”(h]”h ]”h"]”h$]”h&]”uh1hàhjçhžhhŸh¶h Nubah}”(h]”h ]”h"]”h$]”h&]”jjjhjjjÊKuh1hÛhjMhžhhŸh¶h K/ubh¸)”}”(hŒ–Multiplication factor used to grow per-cpu guest_halt_poll_ns when event occurs after per-cpu guest_halt_poll_ns but before global guest_halt_poll_ns.”h]”hŒ–Multiplication factor used to grow per-cpu guest_halt_poll_ns when event occurs after per-cpu guest_halt_poll_ns but before global guest_halt_poll_ns.”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K1hjMhžhubh¸)”}”(hŒ Default: 2”h]”hŒ Default: 2”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K5hjMhžhubhÜ)”}”(hhh]”há)”}”(hŒguest_halt_poll_grow_start: ”h]”h¸)”}”(hŒguest_halt_poll_grow_start:”h]”hŒguest_halt_poll_grow_start:”…””}”(hj+hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K7hj'ubah}”(h]”h ]”h"]”h$]”h&]”uh1hàhj$hžhhŸh¶h Nubah}”(h]”h ]”h"]”h$]”h&]”jjjhjjjÊKuh1hÛhjMhžhhŸh¶h K7ubh¸)”}”(hŒéThe per-cpu guest_halt_poll_ns eventually reaches zero in case of an idle system. This value sets the initial per-cpu guest_halt_poll_ns when growing. This can be increased from 10000, to avoid misses during the initial growth stage:”h]”hŒéThe per-cpu guest_halt_poll_ns eventually reaches zero in case of an idle system. This value sets the initial per-cpu guest_halt_poll_ns when growing. This can be increased from 10000, to avoid misses during the initial growth stage:”…””}”(hjEhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K9hjMhžhubh¸)”}”(hŒ<10k, 20k, 40k, ... (example assumes guest_halt_poll_grow=2).”h]”hŒ<10k, 20k, 40k, ... (example assumes guest_halt_poll_grow=2).”…””}”(hjShžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K?hjMhžhubh¸)”}”(hŒDefault: 50000”h]”hŒDefault: 50000”…””}”(hjahžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KAhjMhžhubhÜ)”}”(hhh]”há)”}”(hŒguest_halt_poll_allow_shrink: ”h]”h¸)”}”(hŒguest_halt_poll_allow_shrink:”h]”hŒguest_halt_poll_allow_shrink:”…””}”(hjvhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KChjrubah}”(h]”h ]”h"]”h$]”h&]”uh1hàhjohžhhŸh¶h Nubah}”(h]”h ]”h"]”h$]”h&]”jjjhjjjÊKuh1hÛhjMhžhhŸh¶h KCubh¸)”}”(hŒ˜Bool parameter which allows shrinking. Set to N to avoid it (per-cpu guest_halt_poll_ns will remain high once achieves global guest_halt_poll_ns value).”h]”hŒ˜Bool parameter which allows shrinking. Set to N to avoid it (per-cpu guest_halt_poll_ns will remain high once achieves global guest_halt_poll_ns value).”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KEhjMhžhubh¸)”}”(hŒ Default: Y”h]”hŒ Default: Y”…””}”(hjžhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KIhjMhžhubh¸)”}”(hŒ:The module parameters can be set from the sysfs files in::”h]”hŒ9The module parameters can be set from the sysfs files in:”…””}”(hj¬hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KKhjMhžhubhŒ literal_block”“”)”}”(hŒ /sys/module/haltpoll/parameters/”h]”hŒ /sys/module/haltpoll/parameters/”…””}”hj¼sbah}”(h]”h ]”h"]”h$]”h&]”Œ xml:space”Œpreserve”uh1jºhŸh¶h KMhjMhžhubeh}”(h]”Œmodule-parameters”ah ]”h"]”Œmodule parameters”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒ Further Notes”h]”hŒ Further Notes”…””}”(hj×hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjÔhžhhŸh¶h KPubhŒ bullet_list”“”)”}”(hhh]”há)”}”(hŒÀCare should be taken when setting the guest_halt_poll_ns parameter as a large value has the potential to drive the cpu usage to 100% on a machine which would be almost entirely idle otherwise.”h]”h¸)”}”(hŒÀCare should be taken when setting the guest_halt_poll_ns parameter as a large value has the potential to drive the cpu usage to 100% on a machine which would be almost entirely idle otherwise.”h]”hŒÀCare should be taken when setting the guest_halt_poll_ns parameter as a large value has the potential to drive the cpu usage to 100% on a machine which would be almost entirely idle otherwise.”…””}”(hjîhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KRhjêubah}”(h]”h ]”h"]”h$]”h&]”uh1hàhjçhžhhŸh¶h Nubah}”(h]”h ]”h"]”h$]”h&]”Œbullet”Œ-”uh1jåhŸh¶h KRhjÔhžhubeh}”(h]”Œ further-notes”ah ]”h"]”Œ further notes”ah$]”h&]”uh1h¡hh£hžhhŸh¶h KPubeh}”(h]”Œguest-halt-polling”ah ]”h"]”Œguest halt polling”ah$]”h&]”uh1h¡hhhžhhŸh¶h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h¶uh1hŒcurrent_source”NŒ current_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¦NŒ generator”NŒ datestamp”NŒ source_link”NŒ source_url”NŒ toc_backlinks”Œentry”Œfootnote_backlinks”KŒ sectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒ strip_classes”NŒ report_level”KŒ halt_level”KŒexit_status_level”KŒdebug”NŒwarning_stream”NŒ traceback”ˆŒinput_encoding”Œ utf-8-sig”Œinput_encoding_error_handler”Œstrict”Œoutput_encoding”Œutf-8”Œoutput_encoding_error_handler”j=Œerror_encoding”Œutf-8”Œerror_encoding_error_handler”Œbackslashreplace”Œ language_code”Œen”Œrecord_dependencies”NŒconfig”NŒ id_prefix”hŒauto_id_prefix”Œid”Œ dump_settings”NŒdump_internals”NŒdump_transforms”NŒdump_pseudo_xml”NŒexpose_internals”NŒstrict_visitor”NŒ_disable_config”NŒ_source”h¶Œ _destination”NŒ _config_files”]”Œ7/var/lib/git/docbuild/linux/Documentation/docutils.conf”aŒfile_insertion_enabled”ˆŒ raw_enabled”KŒline_length_limit”M'Œpep_references”NŒ pep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒ rfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œ smart_quotes”ˆŒsmartquotes_locales”]”Œcharacter_level_inline_markup”‰Œdoctitle_xform”‰Œ docinfo_xform”KŒsectsubtitle_xform”‰Œ image_loading”Œlink”Œembed_stylesheet”‰Œcloak_email_addresses”ˆŒsection_self_link”‰Œenv”NubŒreporter”NŒindirect_targets”]”Œsubstitution_defs”}”Œsubstitution_names”}”Œrefnames”}”Œrefids”}”Œnameids”}”(jjjÑjÎjj uŒ nametypes”}”(j‰jщj‰uh}”(jh£jÎjMj jÔuŒ footnote_refs”}”Œ citation_refs”}”Œ autofootnotes”]”Œautofootnote_refs”]”Œsymbol_footnotes”]”Œsymbol_footnote_refs”]”Œ footnotes”]”Œ citations”]”Œautofootnote_start”KŒsymbol_footnote_start”KŒ id_counter”Œ collections”ŒCounter”“”}”…”R”Œparse_messages”]”(hŒsystem_message”“”)”}”(hhh]”h¸)”}”(hŒ:Enumerated list start value not ordinal-1: "2" (ordinal 2)”h]”hŒ>Enumerated list start value not ordinal-1: “2†(ordinal 2)”…””}”(hj¤hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hj¡ubah}”(h]”h ]”h"]”h$]”h&]”Œlevel”KŒtype”ŒINFO”Œsource”h¶Œline”Kuh1jŸhjMhžhhŸh¶h K(ubj )”}”(hhh]”h¸)”}”(hŒ:Enumerated list start value not ordinal-1: "3" (ordinal 3)”h]”hŒ>Enumerated list start value not ordinal-1: “3†(ordinal 3)”…””}”(hjÀhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hj½ubah}”(h]”h ]”h"]”h$]”h&]”Œlevel”KŒtype”jºŒsource”h¶Œline”Kuh1jŸhjMhžhhŸh¶h K/ubj )”}”(hhh]”h¸)”}”(hŒ:Enumerated list start value not ordinal-1: "4" (ordinal 4)”h]”hŒ>Enumerated list start value not ordinal-1: “4†(ordinal 4)”…””}”(hjÛhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hjØubah}”(h]”h ]”h"]”h$]”h&]”Œlevel”KŒtype”jºŒsource”h¶Œline”Kuh1jŸhjMhžhhŸh¶h K7ubj )”}”(hhh]”h¸)”}”(hŒ:Enumerated list start value not ordinal-1: "5" (ordinal 5)”h]”hŒ>Enumerated list start value not ordinal-1: “5†(ordinal 5)”…””}”(hjöhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hjóubah}”(h]”h ]”h"]”h$]”h&]”Œlevel”KŒtype”jºŒsource”h¶Œline”Kuh1jŸhjMhžhhŸh¶h KCubeŒtransform_messages”]”Œ transformer”NŒ include_log”]”Œ decoration”Nhžhub.