Re: Who's using execute in place?
Thanks for asking, Carsten. I would expect, without samples to cite, that DCSS itself is often used, XIP less so. In my own experience, the lack of interest in XIP follows lack of interest in shared R/O filesystems of any type. (XIP is technically just as easy to maintain, if less well understood, perhaps more difficult to set-up first time.) Since XIP was rolled into EXT2, surely there is little maintenance for Andrew to fuss about. Consistency helps: There should be shared memory on other virtualization platforms. (Apart from deduplication hacks.) DCSS itself could be thought of as another form of reserved memory, not something peculiar to S/390. Also, how does Android addresses flash memory life? It's not read only, but the less writing done the longer flash will last. So following that example, DCSS using JFFS2 might be interesting. (JFFS2 has its own issues with layering violations. Don't get me started.) Apart from Linux on System z, I continue to hear about read-only or write-less-often. Just this week, someone asked my local LUG for suggestions, wanting to know which filesystems drive R/W less fiercely with flash on USB. On Tue, Feb 12, 2013 at 4:36 AM, Carsten Otte co...@de.ibm.com wrote: Dear Linux on z community, a few years ago we've introduced execute in place, which can be used to save some memory by using z/VM DCSS segments. Since the size of main memory for virtual servers has increased much faster than the size of binary executables and libraries since, this technique has become less attractive. Andrew Morton, the leading maintainer for the memory manager in Linux, has raised the question if this is still needed. Who's using execute in place in their environment today? What are your plans of future use? Can we discontinue the technology or shall we keep it around? with kind regards Carsten Otte System z firmware development / Boeblingen lab --- Every revolution was first a thought in one man's mind; and when the same thought occurs to another man, it is the key to that era. - Ralph Waldo Emerson, Essays: First Series, 1841 -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/ -- -- R; Rick Troth Velocity Software http://www.velocitysoftware.com/ -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/
Re: Who's using execute in place?
a few years ago we've introduced execute in place, which can be used to save some memory by using z/VM DCSS segments. Since the size of main memory for virtual servers has increased much faster than the size of binary executables and libraries since, this technique has become less attractive. Andrew Morton, the leading maintainer for the memory manager in Linux, has raised the question if this is still needed. Tolerating that increase in bloat is another problem, but not what you're asking. 8-) That's kinda odd, since it shares a lot of concepts with the code that allows mapping filesystems to PROMs on Intel and ARM. I'm surprised the embedded Linux folks aren't screaming their heads off. Who's using execute in place in their environment today? What are your plans of future use? Can we discontinue the technology or shall we keep it around? We don't use it due to the difficulty of creating and maintaining the DCSS from Linux over time. Since neither of the major distros on Z integrated it into the system management tooling, I suspect that it never got used much and no one would miss it. -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/
Re: Who's using execute in place?
Our reason for not using it is the really high pressure of a very standardized server farm. In order to get this costeffective and useful you should have perhaps only three versions of readonly root filesystems used by all servers. It would be only three systems to upgrade, maximum. Since it is XIP and already in memory, you will get fast boot/reboot and no essential module/lib will ever be paged out, so response time will also be better. As you say, it should be same technology as USB-sticks or memorycards, and it should be std to have that option when installing. We would like to use it, but we have some more standardization to fix first. /Tore Tore Agblad System programmer, Volvo IT certified IT Architect Volvo Information Technology IMO Mainframe Databases zOpen Gothenburg E-mail: tore.agb...@volvo.com http://www.volvo.com/volvoit/global/en-gb/ -Original Message- From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of David Boyes Sent: den 12 februari 2013 15:54 To: LINUX-390@VM.MARIST.EDU Subject: Re: Who's using execute in place? a few years ago we've introduced execute in place, which can be used to save some memory by using z/VM DCSS segments. Since the size of main memory for virtual servers has increased much faster than the size of binary executables and libraries since, this technique has become less attractive. Andrew Morton, the leading maintainer for the memory manager in Linux, has raised the question if this is still needed. Tolerating that increase in bloat is another problem, but not what you're asking. 8-) That's kinda odd, since it shares a lot of concepts with the code that allows mapping filesystems to PROMs on Intel and ARM. I'm surprised the embedded Linux folks aren't screaming their heads off. Who's using execute in place in their environment today? What are your plans of future use? Can we discontinue the technology or shall we keep it around? We don't use it due to the difficulty of creating and maintaining the DCSS from Linux over time. Since neither of the major distros on Z integrated it into the system management tooling, I suspect that it never got used much and no one would miss it. -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/ -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/
Re: Who's using execute in place?
Dear Carsten, We are using DCSS as replacement of a paging device on physical DASD. Works great. I also run the production environment from a DCSS with root and /usr filesystem loaded. So I consider it as a very valuable facility. Kind regards, Florian On Tue, Feb 12, 2013 at 10:36 AM, Carsten Otte co...@de.ibm.com wrote: Dear Linux on z community, a few years ago we've introduced execute in place, which can be used to save some memory by using z/VM DCSS segments. Since the size of main memory for virtual servers has increased much faster than the size of binary executables and libraries since, this technique has become less attractive. Andrew Morton, the leading maintainer for the memory manager in Linux, has raised the question if this is still needed. Who's using execute in place in their environment today? What are your plans of future use? Can we discontinue the technology or shall we keep it around? with kind regards Carsten Otte System z firmware development / Boeblingen lab --- Every revolution was first a thought in one man's mind; and when the same thought occurs to another man, it is the key to that era. - Ralph Waldo Emerson, Essays: First Series, 1841 -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/ -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/
Re: Who's using execute in place?
Hi Florian, please note that the DCSS block device and its use for paging and/or storing file systems on it is not at risk of being discontinued. Are any of your filesystems ext2 with -o xip? with kind regards Carsten Otte System z firmware development / Boeblingen lab --- Every revolution was first a thought in one man's mind; and when the same thought occurs to another man, it is the key to that era. - Ralph Waldo Emerson, Essays: First Series, 1841 Florian Bilek florian.bilek@gm ail.com To Sent by: Linux on LINUX-390@vm.marist.edu, 390 Port cc linux-...@vm.mar ist.edu Subject Re: Who's using execute in place? 12.02.2013 16:48 Please respond to Linux on 390 Port linux-...@vm.mar ist.edu Dear Carsten, We are using DCSS as replacement of a paging device on physical DASD. Works great. I also run the production environment from a DCSS with root and /usr filesystem loaded. So I consider it as a very valuable facility. Kind regards, Florian On Tue, Feb 12, 2013 at 10:36 AM, Carsten Otte co...@de.ibm.com wrote: Dear Linux on z community, a few years ago we've introduced execute in place, which can be used to save some memory by using z/VM DCSS segments. Since the size of main memory for virtual servers has increased much faster than the size of binary executables and libraries since, this technique has become less attractive. Andrew Morton, the leading maintainer for the memory manager in Linux, has raised the question if this is still needed. Who's using execute in place in their environment today? What are your plans of future use? Can we discontinue the technology or shall we keep it around? with kind regards Carsten Otte System z firmware development / Boeblingen lab --- Every revolution was first a thought in one man's mind; and when the same thought occurs to another man, it is the key to that era. - Ralph Waldo Emerson, Essays: First Series, 1841 -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/ -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/ -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/
Re: Who's using execute in place?
I have been wondering if appliances like Texas Memory System (TMS) changes the requirements/direction of items like this? http://www.ramsan.com/ Kurt Acker IBM Smarter Planet, Smarter Data Centers Virtualization and Enterprise System Management Technologies -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/
Re: Who's using execute in place?
On Tuesday, 02/12/2013 at 09:57 EST, David Boyes dbo...@sinenomine.net wrote: We don't use it due to the difficulty of creating and maintaining the DCSS from Linux over time. Since neither of the major distros on Z integrated it into the system management tooling, I suspect that it never got used much and no one would miss it. IMO, as long as the user has to maintain the DCSS it will never catch on. The software vendor must decide what should/shouldn't go into the DCSS, not the sysprog. When you get a service update, the DCSS needs to be re-built automatically if the sysprog has configured its use. And I want to configure its use in only one place. I don't want to have to say 'yes' in File A, and then the name in File B, and for the system to load it in File C. Alan Altmark Senior Managing z/VM and Linux Consultant IBM System Lab Services and Training ibm.com/systems/services/labservices office: 607.429.3323 mobile; 607.321.7556 alan_altm...@us.ibm.com IBM Endicott -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/
Re: Who's using execute in place?
IMO, as long as the user has to maintain the DCSS it will never catch on. Exactly. It's beneficial, but the lack of tooling and implementation integration makes it a PITA. We got plenty of those. The software vendor must decide what should/shouldn't go into the DCSS, not the sysprog. When you get a service update, the DCSS needs to be re- built automatically if the sysprog has configured its use. And I want to configure its use in only one place. I don't want to have to say 'yes' in File A, and then the name in File B, and for the system to load it in File C. Compare to the trigger-based initrd auto-regeneration in modern RHEL, or similar in Debian. That's how it *should* work. -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/
Re: Who's using execute in place?
Agreed. -Original Message- From: Linux on 390 Port [mailto:LINUX-390@VM.MARIST.EDU] On Behalf Of Alan Altmark Sent: Tuesday, February 12, 2013 10:29 AM To: LINUX-390@VM.MARIST.EDU Subject: Re: Who's using execute in place? On Tuesday, 02/12/2013 at 09:57 EST, David Boyes dbo...@sinenomine.net wrote: We don't use it due to the difficulty of creating and maintaining the DCSS from Linux over time. Since neither of the major distros on Z integrated it into the system management tooling, I suspect that it never got used much and no one would miss it. IMO, as long as the user has to maintain the DCSS it will never catch on. The software vendor must decide what should/shouldn't go into the DCSS, not the sysprog. When you get a service update, the DCSS needs to be re-built automatically if the sysprog has configured its use. And I want to configure its use in only one place. I don't want to have to say 'yes' in File A, and then the name in File B, and for the system to load it in File C. Alan Altmark Senior Managing z/VM and Linux Consultant IBM System Lab Services and Training ibm.com/systems/services/labservices office: 607.429.3323 mobile; 607.321.7556 alan_altm...@us.ibm.com IBM Endicott -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/ -- For LINUX-390 subscribe / signoff / archive access instructions, send email to lists...@vm.marist.edu with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 -- For more information on Linux on System z, visit http://wiki.linuxvm.org/
