€•TyŒsphinx.addnodes”Œdocument”“”)”}”(Œ rawsource”Œ”Œchildren”]”(Œtranslations”Œ LanguagesNode”“”)”}”(hhh]”(hŒpending_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/arch/s390/monreader”Œmodname”NŒ classname”NŒrefexplicit”ˆuŒtagname”hhhubh)”}”(hhh]”hŒChinese (Traditional)”…””}”hh2sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ'/translations/zh_TW/arch/s390/monreader”Œmodname”NŒ classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒItalian”…””}”hhFsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ'/translations/it_IT/arch/s390/monreader”Œmodname”NŒ classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒJapanese”…””}”hhZsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ'/translations/ja_JP/arch/s390/monreader”Œmodname”NŒ classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒKorean”…””}”hhnsbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ'/translations/ko_KR/arch/s390/monreader”Œmodname”NŒ classname”NŒrefexplicit”ˆuh1hhhubh)”}”(hhh]”hŒSpanish”…””}”hh‚sbah}”(h]”h ]”h"]”h$]”h&]”Œ refdomain”h)Œreftype”h+Œ reftarget”Œ'/translations/sp_SP/arch/s390/monreader”Œmodname”NŒ classname”NŒrefexplicit”ˆuh1hhhubeh}”(h]”h ]”h"]”h$]”h&]”Œcurrent_language”ŒEnglish”uh1h hhŒ _document”hŒsource”NŒline”NubhŒsection”“”)”}”(hhh]”(hŒtitle”“”)”}”(hŒ1Linux API for read access to z/VM Monitor Records”h]”hŒ1Linux API for read access to z/VM Monitor Records”…””}”(hh¨hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hh£hžhhŸŒA/var/lib/git/docbuild/linux/Documentation/arch/s390/monreader.rst”h KubhŒ paragraph”“”)”}”(hŒDate : 2004-Nov-26”h]”hŒDate : 2004-Nov-26”…””}”(hh¹hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¸)”}”(hŒ-Author: Gerald Schaefer (geraldsc@de.ibm.com)”h]”(hŒAuthor: Gerald Schaefer (”…””}”(hhÇhžhhŸNh NubhŒ reference”“”)”}”(hŒgeraldsc@de.ibm.com”h]”hŒgeraldsc@de.ibm.com”…””}”(hhÑhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”Œmailto:geraldsc@de.ibm.com”uh1hÏhhÇubhŒ)”…””}”(hhÇhžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khh£hžhubh¢)”}”(hhh]”(h§)”}”(hŒDescription”h]”hŒDescription”…””}”(hhîhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hhëhžhhŸh¶h K ubh¸)”}”(hŒÊThis item delivers a new Linux API in the form of a misc char device that is usable from user space and allows read access to the z/VM Monitor Records collected by the `*MONITOR` System Service of z/VM.”h]”(hŒ¨This item delivers a new Linux API in the form of a misc char device that is usable from user space and allows read access to the z/VM Monitor Records collected by the ”…””}”(hhühžhhŸNh NubhŒtitle_reference”“”)”}”(hŒ `*MONITOR`”h]”hŒ*MONITOR”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhhüubhŒ System Service of z/VM.”…””}”(hhühžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khhëhžhubeh}”(h]”Œdescription”ah ]”h"]”Œdescription”ah$]”h&]”uh1h¡hh£hžhhŸh¶h K ubh¢)”}”(hhh]”(h§)”}”(hŒUser Requirements”h]”hŒUser Requirements”…””}”(hj)hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj&hžhhŸh¶h Kubh¸)”}”(hXÆThe z/VM guest on which you want to access this API needs to be configured in order to allow IUCV connections to the `*MONITOR` service, i.e. it needs the IUCV `*MONITOR` statement in its user entry. If the monitor DCSS to be used is restricted (likely), you also need the NAMESAVE statement. This item will use the IUCV device driver to access the z/VM services, so you need a kernel with IUCV support. You also need z/VM version 4.4 or 5.1.”h]”(hŒuThe z/VM guest on which you want to access this API needs to be configured in order to allow IUCV connections to the ”…””}”(hj7hžhhŸNh Nubj)”}”(hŒ `*MONITOR`”h]”hŒ*MONITOR”…””}”(hj?hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj7ubhŒ! service, i.e. it needs the IUCV ”…””}”(hj7hžhhŸNh Nubj)”}”(hŒ `*MONITOR`”h]”hŒ*MONITOR”…””}”(hjQhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj7ubhX statement in its user entry. If the monitor DCSS to be used is restricted (likely), you also need the NAMESAVE statement. This item will use the IUCV device driver to access the z/VM services, so you need a kernel with IUCV support. You also need z/VM version 4.4 or 5.1.”…””}”(hj7hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj&hžhubh¸)”}”(hX)There are two options for being able to load the monitor DCSS (examples assume that the monitor DCSS begins at 144 MB and ends at 152 MB). You can query the location of the monitor DCSS with the Class E privileged CP command Q NSS MAP (the values BEGPAG and ENDPAG are given in units of 4K pages).”h]”hX)There are two options for being able to load the monitor DCSS (examples assume that the monitor DCSS begins at 144 MB and ends at 152 MB). You can query the location of the monitor DCSS with the Class E privileged CP command Q NSS MAP (the values BEGPAG and ENDPAG are given in units of 4K pages).”…””}”(hjihžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khj&hžhubh¸)”}”(hŒÞSee also "CP Command and Utility Reference" (SC24-6081-00) for more information on the DEF STOR and Q NSS MAP commands, as well as "Saved Segments Planning and Administration" (SC24-6116-00) for more information on DCSSes.”h]”hŒæSee also â€œCP Command and Utility Referenceâ€ (SC24-6081-00) for more information on the DEF STOR and Q NSS MAP commands, as well as â€œSaved Segments Planning and Administrationâ€ (SC24-6116-00) for more information on DCSSes.”…””}”(hjwhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K!hj&hžhubh¢)”}”(hhh]”(h§)”}”(hŒ1st option:”h]”hŒ1st option:”…””}”(hjˆhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj…hžhhŸh¶h K&ubh¸)”}”(hŒˆYou can use the CP command DEF STOR CONFIG to define a "memory hole" in your guest virtual storage around the address range of the DCSS.”h]”hŒŒYou can use the CP command DEF STOR CONFIG to define a â€œmemory holeâ€ in your guest virtual storage around the address range of the DCSS.”…””}”(hj–hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K'hj…hžhubh¸)”}”(hŒ)Example: DEF STOR CONFIG 0.140M 200M.200M”h]”hŒ)Example: DEF STOR CONFIG 0.140M 200M.200M”…””}”(hj¤hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K*hj…hžhubh¸)”}”(hX This defines two blocks of storage, the first is 140MB in size an begins at address 0MB, the second is 200MB in size and begins at address 200MB, resulting in a total storage of 340MB. Note that the first block should always start at 0 and be at least 64MB in size.”h]”hX This defines two blocks of storage, the first is 140MB in size an begins at address 0MB, the second is 200MB in size and begins at address 200MB, resulting in a total storage of 340MB. Note that the first block should always start at 0 and be at least 64MB in size.”…””}”(hj²hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K,hj…hžhubeh}”(h]”Œ st-option”ah ]”h"]”Œ1st option:”ah$]”h&]”uh1h¡hj&hžhhŸh¶h K&ubh¢)”}”(hhh]”(h§)”}”(hŒ2nd option:”h]”hŒ2nd option:”…””}”(hjËhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjÈhžhhŸh¶h K2ubh¸)”}”(hŒËYour guest virtual storage has to end below the starting address of the DCSS and you have to specify the "mem=" kernel parameter in your parmfile with a value greater than the ending address of the DCSS.”h]”hŒÏYour guest virtual storage has to end below the starting address of the DCSS and you have to specify the â€œmem=â€ kernel parameter in your parmfile with a value greater than the ending address of the DCSS.”…””}”(hjÙhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K3hjÈhžhubh¸)”}”(hŒ Example::”h]”hŒExample:”…””}”(hjçhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K7hjÈhžhubhŒ literal_block”“”)”}”(hŒ DEF STOR 140M”h]”hŒ DEF STOR 140M”…””}”hj÷sbah}”(h]”h ]”h"]”h$]”h&]”Œ xml:space”Œpreserve”uh1jõhŸh¶h K9hjÈhžhubh¸)”}”(hŒbThis defines 140MB storage size for your guest, the parameter "mem=160M" is added to the parmfile.”h]”hŒfThis defines 140MB storage size for your guest, the parameter â€œmem=160Mâ€ is added to the parmfile.”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K;hjÈhžhubeh}”(h]”Œ nd-option”ah ]”h"]”Œ2nd option:”ah$]”h&]”uh1h¡hj&hžhhŸh¶h K2ubeh}”(h]”Œuser-requirements”ah ]”h"]”Œuser requirements”ah$]”h&]”uh1h¡hh£hžhhŸh¶h Kubh¢)”}”(hhh]”(h§)”}”(hŒUser Interface”h]”hŒUser Interface”…””}”(hj(hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj%hžhhŸh¶h K@ubh¸)”}”(hX‹The char device is implemented as a kernel module named "monreader", which can be loaded via the modprobe command, or it can be compiled into the kernel instead. There is one optional module (or kernel) parameter, "mondcss", to specify the name of the monitor DCSS. If the module is compiled into the kernel, the kernel parameter "monreader.mondcss=" can be specified in the parmfile.”h]”hX—The char device is implemented as a kernel module named â€œmonreaderâ€, which can be loaded via the modprobe command, or it can be compiled into the kernel instead. There is one optional module (or kernel) parameter, â€œmondcssâ€, to specify the name of the monitor DCSS. If the module is compiled into the kernel, the kernel parameter â€œmonreader.mondcss=â€ can be specified in the parmfile.”…””}”(hj6hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KAhj%hžhubh¸)”}”(hX=The default name for the DCSS is "MONDCSS" if none is specified. In case that there are other users already connected to the `*MONITOR` service (e.g. Performance Toolkit), the monitor DCSS is already defined and you have to use the same DCSS. The CP command Q MONITOR (Class E privileged) shows the name of the monitor DCSS, if already defined, and the users connected to the `*MONITOR` service. Refer to the "z/VM Performance" book (SC24-6109-00) on how to create a monitor DCSS if your z/VM doesn't have one already, you need Class E privileges to define and save a DCSS.”h]”(hŒThe default name for the DCSS is â€œMONDCSSâ€ if none is specified. In case that there are other users already connected to the ”…””}”(hjDhžhhŸNh Nubj)”}”(hŒ `*MONITOR`”h]”hŒ*MONITOR”…””}”(hjLhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhjDubhŒñ service (e.g. Performance Toolkit), the monitor DCSS is already defined and you have to use the same DCSS. The CP command Q MONITOR (Class E privileged) shows the name of the monitor DCSS, if already defined, and the users connected to the ”…””}”(hjDhžhhŸNh Nubj)”}”(hŒ `*MONITOR`”h]”hŒ*MONITOR”…””}”(hj^hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhjDubhŒÁ service. Refer to the â€œz/VM Performanceâ€ book (SC24-6109-00) on how to create a monitor DCSS if your z/VM doesnâ€™t have one already, you need Class E privileges to define and save a DCSS.”…””}”(hjDhžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KHhj%hžhubh¢)”}”(hhh]”(h§)”}”(hŒExample:”h]”hŒExample:”…””}”(hjyhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjvhžhhŸh¶h KSubjö)”}”(hŒ!modprobe monreader mondcss=MYDCSS”h]”hŒ!modprobe monreader mondcss=MYDCSS”…””}”hj‡sbah}”(h]”h ]”h"]”h$]”h&]”jjuh1jõhŸh¶h KWhjvhžhubh¸)”}”(hŒ9This loads the module and sets the DCSS name to "MYDCSS".”h]”hŒ=This loads the module and sets the DCSS name to â€œMYDCSSâ€.”…””}”(hj•hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KYhjvhžhubeh}”(h]”Œexample”ah ]”h"]”h$]”Œexample:”ah&]”uh1h¡hj%hžhhŸh¶h KSŒ referenced”Kubh¢)”}”(hhh]”(h§)”}”(hŒNOTE:”h]”hŒNOTE:”…””}”(hj¯hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hj¬hžhhŸh¶h K\ubh¸)”}”(hŒ×This API provides no interface to control the `*MONITOR` service, e.g. specify which data should be collected. This can be done by the CP command MONITOR (Class E privileged), see "CP Command and Utility Reference".”h]”(hŒ.This API provides no interface to control the ”…””}”(hj½hžhhŸNh Nubj)”}”(hŒ `*MONITOR`”h]”hŒ*MONITOR”…””}”(hjÅhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj½ubhŒ£ service, e.g. specify which data should be collected. This can be done by the CP command MONITOR (Class E privileged), see â€œCP Command and Utility Referenceâ€.”…””}”(hj½hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K]hj¬hžhubeh}”(h]”Œnote”ah ]”h"]”h$]”Œnote:”ah&]”uh1h¡hj%hžhhŸh¶h K\j«Kubh¢)”}”(hhh]”(h§)”}”(hŒDevice nodes with udev:”h]”hŒDevice nodes with udev:”…””}”(hjèhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjåhžhhŸh¶h Kbubh¸)”}”(hŒoAfter loading the module, a char device will be created along with the device node //monreader.”h]”hŒoAfter loading the module, a char device will be created along with the device node //monreader.”…””}”(hjöhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Kchjåhžhubeh}”(h]”Œdevice-nodes-with-udev”ah ]”h"]”Œdevice nodes with udev:”ah$]”h&]”uh1h¡hj%hžhhŸh¶h Kbubh¢)”}”(hhh]”(h§)”}”(hŒDevice nodes without udev:”h]”hŒDevice nodes without udev:”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjhžhhŸh¶h Kgubh¸)”}”(hXIf your distribution does not support udev, a device node will not be created automatically and you have to create it manually after loading the module. Therefore you need to know the major and minor numbers of the device. These numbers can be found in /sys/class/misc/monreader/dev.”h]”hXIf your distribution does not support udev, a device node will not be created automatically and you have to create it manually after loading the module. Therefore you need to know the major and minor numbers of the device. These numbers can be found in /sys/class/misc/monreader/dev.”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khhjhžhubh¸)”}”(hŒðTyping cat /sys/class/misc/monreader/dev will give an output of the form :. The device node can be created via the mknod command, enter mknod c , where is the name of the device node to be created.”h]”hŒðTyping cat /sys/class/misc/monreader/dev will give an output of the form :. The device node can be created via the mknod command, enter mknod c , where is the name of the device node to be created.”…””}”(hj+hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Kmhjhžhubeh}”(h]”Œdevice-nodes-without-udev”ah ]”h"]”Œdevice nodes without udev:”ah$]”h&]”uh1h¡hj%hžhhŸh¶h Kgubh¢)”}”(hhh]”(h§)”}”(hŒExample:”h]”hŒExample:”…””}”(hjDhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjAhžhhŸh¶h Ksubjö)”}”(hŒ]# modprobe monreader # cat /sys/class/misc/monreader/dev 10:63 # mknod /dev/monreader c 10 63”h]”hŒ]# modprobe monreader # cat /sys/class/misc/monreader/dev 10:63 # mknod /dev/monreader c 10 63”…””}”hjRsbah}”(h]”h ]”h"]”h$]”h&]”jjuh1jõhŸh¶h KwhjAhžhubh¸)”}”(hŒXThis loads the module with the default monitor DCSS (MONDCSS) and creates a device node.”h]”hŒXThis loads the module with the default monitor DCSS (MONDCSS) and creates a device node.”…””}”(hj`hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K|hjAhžhubeh}”(h]”Œid1”ah ]”h"]”h$]”j©ah&]”uh1h¡hj%hžhhŸh¶h Ksj«Kubh¢)”}”(hhh]”(h§)”}”(hŒFile operations:”h]”hŒFile operations:”…””}”(hjxhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjuhžhhŸh¶h K€ubh¸)”}”(hŒèThe following file operations are supported: open, release, read, poll. There are two alternative methods for reading: either non-blocking read in conjunction with polling, or blocking read without polling. IOCTLs are not supported.”h]”hŒèThe following file operations are supported: open, release, read, poll. There are two alternative methods for reading: either non-blocking read in conjunction with polling, or blocking read without polling. IOCTLs are not supported.”…””}”(hj†hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Khjuhžhubeh}”(h]”Œfile-operations”ah ]”h"]”Œfile operations:”ah$]”h&]”uh1h¡hj%hžhhŸh¶h K€ubh¢)”}”(hhh]”(h§)”}”(hŒRead:”h]”hŒRead:”…””}”(hjŸhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjœhžhhŸh¶h K‡ubh¸)”}”(hXæReading from the device provides a 12 Byte monitor control element (MCE), followed by a set of one or more contiguous monitor records (similar to the output of the CMS utility MONWRITE without the 4K control blocks). The MCE contains information on the type of the following record set (sample/event data), the monitor domains contained within it and the start and end address of the record set in the monitor DCSS. The start and end address can be used to determine the size of the record set, the end address is the address of the last byte of data. The start address is needed to handle "end-of-frame" records correctly (domain 1, record 13), i.e. it can be used to determine the record start offset relative to a 4K page (frame) boundary.”h]”hXêReading from the device provides a 12 Byte monitor control element (MCE), followed by a set of one or more contiguous monitor records (similar to the output of the CMS utility MONWRITE without the 4K control blocks). The MCE contains information on the type of the following record set (sample/event data), the monitor domains contained within it and the start and end address of the record set in the monitor DCSS. The start and end address can be used to determine the size of the record set, the end address is the address of the last byte of data. The start address is needed to handle â€œend-of-frameâ€ records correctly (domain 1, record 13), i.e. it can be used to determine the record start offset relative to a 4K page (frame) boundary.”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Kˆhjœhžhubh¸)”}”(hŒæSee "Appendix A: `*MONITOR`" in the "z/VM Performance" document for a description of the monitor control element layout. The layout of the monitor records can be found here (z/VM 5.1): https://www.vm.ibm.com/pubs/mon510/index.html”h]”(hŒSee â€œAppendix A: ”…””}”(hj»hžhhŸNh Nubj)”}”(hŒ `*MONITOR`”h]”hŒ*MONITOR”…””}”(hjÃhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj»ubhŒ¤â€ in the â€œz/VM Performanceâ€ document for a description of the monitor control element layout. The layout of the monitor records can be found here (z/VM 5.1): ”…””}”(hj»hžhhŸNh NubhÐ)”}”(hŒ-https://www.vm.ibm.com/pubs/mon510/index.html”h]”hŒ-https://www.vm.ibm.com/pubs/mon510/index.html”…””}”(hjÕhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”Œrefuri”j×uh1hÏhj»ubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K“hjœhžhubh¸)”}”(hŒNThe layout of the data stream provided by the monreader device is as follows::”h]”hŒMThe layout of the data stream provided by the monreader device is as follows:”…””}”(hjêhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K—hjœhžhubjö)”}”(hŒ·... <0 byte read> \ | ... |- data set | / <0 byte read> ...”h]”hŒ·... <0 byte read> \ | ... |- data set | / <0 byte read> ...”…””}”hjøsbah}”(h]”h ]”h"]”h$]”h&]”jjuh1jõhŸh¶h K™hjœhžhubh¸)”}”(hXThere may be more than one combination of MCE and corresponding record set within one data set and the end of each data set is indicated by a successful read with a return value of 0 (0 byte read). Any received data must be considered invalid until a complete set was read successfully, including the closing 0 byte read. Therefore you should always read the complete set into a buffer before processing the data.”h]”hXThere may be more than one combination of MCE and corresponding record set within one data set and the end of each data set is indicated by a successful read with a return value of 0 (0 byte read). Any received data must be considered invalid until a complete set was read successfully, including the closing 0 byte read. Therefore you should always read the complete set into a buffer before processing the data.”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K£hjœhžhubh¸)”}”(hX^The maximum size of a data set can be as large as the size of the monitor DCSS, so design the buffer adequately or use dynamic memory allocation. The size of the monitor DCSS will be printed into syslog after loading the module. You can also use the (Class E privileged) CP command Q NSS MAP to list all available segments and information about them.”h]”hX^The maximum size of a data set can be as large as the size of the monitor DCSS, so design the buffer adequately or use dynamic memory allocation. The size of the monitor DCSS will be printed into syslog after loading the module. You can also use the (Class E privileged) CP command Q NSS MAP to list all available segments and information about them.”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h Kªhjœhžhubh¸)”}”(hŒµAs with most char devices, error conditions are indicated by returning a negative value for the number of bytes read. In this case, the errno variable indicates the error condition:”h]”hŒµAs with most char devices, error conditions are indicated by returning a negative value for the number of bytes read. In this case, the errno variable indicates the error condition:”…””}”(hj"hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K°hjœhžhubhŒdefinition_list”“”)”}”(hhh]”(hŒdefinition_list_item”“”)”}”(hŒ„EIO: reply failed, read data is invalid and the application should discard the data read since the last successful read with 0 size.”h]”(hŒterm”“”)”}”(hŒEIO:”h]”hŒEIO:”…””}”(hj=hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j;hŸh¶h Kµhj7ubhŒ definition”“”)”}”(hhh]”h¸)”}”(hŒreply failed, read data is invalid and the application should discard the data read since the last successful read with 0 size.”h]”hŒreply failed, read data is invalid and the application should discard the data read since the last successful read with 0 size.”…””}”(hjPhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KµhjMubah}”(h]”h ]”h"]”h$]”h&]”uh1jKhj7ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j5hŸh¶h Kµhj2ubj6)”}”(hŒŽEFAULT: copy_to_user failed, read data is invalid and the application should discard the data read since the last successful read with 0 size.”h]”(j<)”}”(hŒEFAULT:”h]”hŒEFAULT:”…””}”(hjnhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j;hŸh¶h K¸hjjubjL)”}”(hhh]”h¸)”}”(hŒ†copy_to_user failed, read data is invalid and the application should discard the data read since the last successful read with 0 size.”h]”hŒ†copy_to_user failed, read data is invalid and the application should discard the data read since the last successful read with 0 size.”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K¸hj|ubah}”(h]”h ]”h"]”h$]”h&]”uh1jKhjjubeh}”(h]”h ]”h"]”h$]”h&]”uh1j5hŸh¶h K¸hj2hžhubj6)”}”(hŒ¶EAGAIN: occurs on a non-blocking read if there is no data available at the moment. There is no data missing or corrupted, just try again or rather use polling for non-blocking reads.”h]”(j<)”}”(hŒEAGAIN:”h]”hŒEAGAIN:”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j;hŸh¶h K¼hj™ubjL)”}”(hhh]”h¸)”}”(hŒ®occurs on a non-blocking read if there is no data available at the moment. There is no data missing or corrupted, just try again or rather use polling for non-blocking reads.”h]”hŒ®occurs on a non-blocking read if there is no data available at the moment. There is no data missing or corrupted, just try again or rather use polling for non-blocking reads.”…””}”(hj®hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K»hj«ubah}”(h]”h ]”h"]”h$]”h&]”uh1jKhj™ubeh}”(h]”h ]”h"]”h$]”h&]”uh1j5hŸh¶h K¼hj2hžhubj6)”}”(hŒ‹EOVERFLOW: message limit reached, the data read since the last successful read with 0 size is valid but subsequent records may be missing. ”h]”(j<)”}”(hŒ EOVERFLOW:”h]”hŒ EOVERFLOW:”…””}”(hjÌhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1j;hŸh¶h KÀhjÈubjL)”}”(hhh]”h¸)”}”(hŒmessage limit reached, the data read since the last successful read with 0 size is valid but subsequent records may be missing.”h]”hŒmessage limit reached, the data read since the last successful read with 0 size is valid but subsequent records may be missing.”…””}”(hjÝhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h K¿hjÚubah}”(h]”h ]”h"]”h$]”h&]”uh1jKhjÈubeh}”(h]”h ]”h"]”h$]”h&]”uh1j5hŸh¶h KÀhj2hžhubeh}”(h]”h ]”h"]”h$]”h&]”uh1j0hjœhžhhŸh¶h Nubh¸)”}”(hŒÏIn the last case (EOVERFLOW) there may be missing data, in the first two cases (EIO, EFAULT) there will be missing data. It's up to the application if it will continue reading subsequent data or rather exit.”h]”hŒÑIn the last case (EOVERFLOW) there may be missing data, in the first two cases (EIO, EFAULT) there will be missing data. Itâ€™s up to the application if it will continue reading subsequent data or rather exit.”…””}”(hjýhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KÂhjœhžhubeh}”(h]”Œread”ah ]”h"]”Œread:”ah$]”h&]”uh1h¡hj%hžhhŸh¶h K‡ubh¢)”}”(hhh]”(h§)”}”(hŒOpen:”h]”hŒOpen:”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjhžhhŸh¶h KÇubh¸)”}”(hXÂOnly one user is allowed to open the char device. If it is already in use, the open function will fail (return a negative value) and set errno to EBUSY. The open function may also fail if an IUCV connection to the `*MONITOR` service cannot be established. In this case errno will be set to EIO and an error message with an IPUSER SEVER code will be printed into syslog. The IPUSER SEVER codes are described in the "z/VM Performance" book, Appendix A.”h]”(hŒÖOnly one user is allowed to open the char device. If it is already in use, the open function will fail (return a negative value) and set errno to EBUSY. The open function may also fail if an IUCV connection to the ”…””}”(hj$hžhhŸNh Nubj)”}”(hŒ `*MONITOR`”h]”hŒ*MONITOR”…””}”(hj,hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1jhj$ubhŒæ service cannot be established. In this case errno will be set to EIO and an error message with an IPUSER SEVER code will be printed into syslog. The IPUSER SEVER codes are described in the â€œz/VM Performanceâ€ book, Appendix A.”…””}”(hj$hžhhŸNh Nubeh}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KÈhjhžhubeh}”(h]”Œopen”ah ]”h"]”Œopen:”ah$]”h&]”uh1h¡hj%hžhhŸh¶h KÇubh¢)”}”(hhh]”(h§)”}”(hŒNOTE:”h]”hŒNOTE:”…””}”(hjOhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h¦hjLhžhhŸh¶h KÐubh¸)”}”(hŒòAs soon as the device is opened, incoming messages will be accepted and they will account for the message limit, i.e. opening the device without reading from it will provoke the "message limit reached" error (EOVERFLOW error code) eventually.”h]”hŒöAs soon as the device is opened, incoming messages will be accepted and they will account for the message limit, i.e. opening the device without reading from it will provoke the â€œmessage limit reachedâ€ error (EOVERFLOW error code) eventually.”…””}”(hj]hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hŸh¶h KÑhjLhžhubeh}”(h]”Œid2”ah ]”h"]”h$]”jãah&]”uh1h¡hj%hžhhŸh¶h KÐj«Kubeh}”(h]”Œuser-interface”ah ]”h"]”Œuser interface”ah$]”h&]”uh1h¡hh£hžhhŸh¶h K@ubeh}”(h]”Œ1linux-api-for-read-access-to-z-vm-monitor-records”ah ]”h"]”Œ1linux api for read access to z/vm monitor records”ah$]”h&]”uh1h¡hhhžhhŸh¶h Kubeh}”(h]”h ]”h"]”h$]”h&]”Œsource”h¶uh1hŒcurrent_source”NŒcurrent_line”NŒsettings”Œdocutils.frontend”ŒValues”“”)”}”(h¦NŒ generator”NŒ datestamp”NŒsource_link”NŒ source_url”NŒ toc_backlinks”Œentry”Œfootnote_backlinks”KŒ sectnum_xform”KŒstrip_comments”NŒstrip_elements_with_classes”NŒ strip_classes”NŒreport_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”ˆŒraw_enabled”KŒline_length_limit”M'Œpep_references”NŒpep_base_url”Œhttps://peps.python.org/”Œpep_file_url_template”Œpep-%04d”Œrfc_references”NŒrfc_base_url”Œ&https://datatracker.ietf.org/doc/html/”Œ tab_width”KŒtrim_footnote_reference_space”‰Œsyntax_highlight”Œlong”Œsmart_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”}”(jj|j#j j"jjÅjÂjjjwjtŒexample:”NŒnote:”Nj jj>j;j™j–jj jIjFuŒ nametypes”}”(j‰j#‰j"‰jÅ‰j‰jw‰jé‰jê‰j ‰j>‰j™‰j‰jI‰uh}”(j|h£j hëjj&jÂj…jjÈjtj%j¥jvjßj¬jjåj;jjpjAj–juj jœjFjjmjLuŒ 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”Œcollections”ŒCounter”“”}”j³Ks…”R”Œparse_messages”]”(hŒsystem_message”“”)”}”(hhh]”h¸)”}”(hŒ+Duplicate implicit target name: "example:".”h]”hŒ/Duplicate implicit target name: â€œexample:â€.”…””}”(hjhžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hjubah}”(h]”h ]”h"]”h$]”h&]”jpaŒlevel”KŒtype”ŒINFO”Œsource”h¶Œline”Ksuh1j hjAhžhhŸh¶h Ksubj )”}”(hhh]”h¸)”}”(hŒ(Duplicate implicit target name: "note:".”h]”hŒ,Duplicate implicit target name: â€œnote:â€.”…””}”(hj*hžhhŸNh Nubah}”(h]”h ]”h"]”h$]”h&]”uh1h·hj'ubah}”(h]”h ]”h"]”h$]”h&]”jmaŒlevel”KŒtype”j$Œsource”h¶Œline”KÐuh1j hjLhžhhŸh¶h KÐubeŒtransform_messages”]”Œtransformer”NŒinclude_log”]”Œ decoration”Nhžhub.