Hello hpa, We are developing a Xen-based virtualization service, and we are trying to reduce excessive CPU utilization at isolinux boot prompts. When users boot up a virtual machine on an isolinux boot CD, the CPU starts spinning at 100%. These machines frequently get left in this state for days or weeks, degrading the service for everyone else. You replied to the work-around discussed in the earlier thread at http://syslinux.zytor.com/archives/2005-June/005291.html > Breaks serial console. > -hpa In our case, the serial console is not an issue. We would like to submit a patch to isolinux which HLTs on getchar if isolinux is not running with the serial console option. Do you think this is the right solution to this problem? Can we work with you to resolve this? Thanks, -Peter Iannucci MIT Student Information Processing Board -------------- next part -------------- A non-text attachment was scrubbed... Name: smime.p7s Type: application/x-pkcs7-signature Size: 2713 bytes Desc: S/MIME Cryptographic Signature URL: <http://www.zytor.com/pipermail/syslinux/attachments/20090502/8eb84eec/attachment.bin>
Peter Iannucci wrote:> Hello hpa, > > We are developing a Xen-based virtualization service, and we are trying > to reduce excessive CPU utilization at isolinux boot prompts. When > users boot up a virtual machine on an isolinux boot CD, the CPU starts > spinning at 100%. These machines frequently get left in this state for > days or weeks, degrading the service for everyone else. > > You replied to the work-around discussed in the earlier thread at > > http://syslinux.zytor.com/archives/2005-June/005291.html > >> Breaks serial console. >> -hpa > > In our case, the serial console is not an issue. We would like to > submit a patch to isolinux which HLTs on getchar if isolinux is not > running with the serial console option. Do you think this is the right > solution to this problem? Can we work with you to resolve this? >It would *probably* be okay to do when serial console is not enabled, but it seems a bit crude... and also it's somewhat confusing that one should enable serial console and get drastically different behavior. What is much more confusing to me is why do you have VMs left like this for "days or weeks"? -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.
On Sat, 2 May 2009, Peter Iannucci wrote:> In our case, the serial console is not an issue. We would like to submit a > patch to isolinux which HLTs on getchar if isolinux is not running with the > serial console option. Do you think this is the right solution to this > problem? Can we work with you to resolve this?I support you on this, I brought this on the table last year too. We are not using serial console and this is a big issue for us too. In our case we do CD-based anaconda installations that (on success) automatically reboot. Since we cannot eject these virtual ISO images they wait on the isolinux bootprompt after this reboot. It may take a few days (in some cases were we do test installations weeks) before the machines are booted (or re-installed) and it is wasting CPU power. On a physical machine it's less disturbing since it is dedicated hardware (still not OK for green computing) but in virtualization this is a huge problem. -- -- dag wieers, dag at wieers.com, http://dag.wieers.com/ -- [Any errors in spelling, tact or fact are transmission errors]
Sebastian Herbszt wrote:> H. Peter Anvin wrote: >> Keep in mind that if you have control over the configuration it might be >> preferrable to set a totaltimeout which shuts down the domain... > > How would one do this? I assume it's something like > > TOTALTIMEOUT 9000 > DEFAULT apm_poweroff.com > > where apm_poweroff.com would try to use INT 15h, AX = 5307h?Seems to work in Bochs and QEMU. - Sebastian