tag:blogger.com,1999:blog-8336326562741944626.post2520799697216788302..comments2023-11-03T01:34:26.403-07:00Comments on CRiSP, DTrace, and other technobabble: Dtrace .. does it work. Yes. No. Yes. No. What?!Crisp Editorhttp://www.blogger.com/profile/14144625547464350210noreply@blogger.comBlogger6125tag:blogger.com,1999:blog-8336326562741944626.post-15951894726410484112011-10-31T01:02:19.259-07:002011-10-31T01:02:19.259-07:00The http://www.linux-kvm.org/wiki/images/7/71/2011...The http://www.linux-kvm.org/wiki/images/7/71/2011-forum-porting-to-smartos.pdf article is an interesting and enlightening read.<br /><br />I cant see any relevance to using SmartOS to dive into Linux - it doesnt help for a native Linux port of Dtrace, although it can be useful for other linux kernel work (eg profiling and experimentation).<br /><br />I have resolved the latest kernel hangs - this is solely a bug in linux's printk() implementation, which is attempting to be too smart. It is not allowing recursive printks - recursive printks are bizarre, but, when you need them, you need them bad. <br /><br />It highlights a naughtyism in my code, so I can now work to remove these (and avoid wasteful pollution of the /var/log/messages file).Paul Foxhttps://www.blogger.com/profile/11969759101059066480noreply@blogger.comtag:blogger.com,1999:blog-8336326562741944626.post-78763602239503915062011-10-30T19:47:14.504-07:002011-10-30T19:47:14.504-07:00Hi Nigel,
Unfortunately, details seem a bit spars...Hi Nigel,<br /><br />Unfortunately, details seem a bit sparse on the exact setup. The links I've been able to find are:<br />http://www.linux-kvm.org/wiki/images/7/71/2011-forum-porting-to-smartos.pdf<br />http://dtrace.org/blogs/bmc/<br />http://planet.illumos.org/otoburbhttps://www.blogger.com/profile/01399613011609624145noreply@blogger.comtag:blogger.com,1999:blog-8336326562741944626.post-10026259506063624672011-10-30T16:32:41.936-07:002011-10-30T16:32:41.936-07:00Otoburb, has anything been published, that demonst...Otoburb, has anything been published, that demonstrates how you can use the SmartOS DTrace to trace into Linux running under KVM?Nigel W Smithhttps://www.blogger.com/profile/08381869598305700143noreply@blogger.comtag:blogger.com,1999:blog-8336326562741944626.post-73263091195288445442011-10-29T22:51:30.711-07:002011-10-29T22:51:30.711-07:00Sorry, I didn't meant to be cryptic. I was ref...Sorry, I didn't meant to be cryptic. I was referring to the process that Joyent used to port the Linux Kernel Virtual Machine from Linux to SmartOS. <br /><br />Joyent is the company that created their own operating system called SmartOS, which is based on an OpenSolaris fork called IllumOS. <br /><br />One of the Sun Dtrace creators works for Joyent. As part of the KVM porting process, he used a SmartOS host system, and then virtualized an instance of Linux within the host. This meant that he could use Dtrace (which is supposedly fully functional within SmartOS) to debug and trace kernel issues with the running Linux instance. <br /><br />You were referring in your post to trying to debug "you died but I am not going to tell you why" issues; I was suggesting that in lieu of writing your own kernel debugger, perhaps you could use the same method that Joyent uses to debug Linux kernel/KVM issues, especially in light of your familiarity with Dtrace probes already.otoburbhttps://www.blogger.com/profile/01399613011609624145noreply@blogger.comtag:blogger.com,1999:blog-8336326562741944626.post-41997431031645050692011-10-29T13:53:54.109-07:002011-10-29T13:53:54.109-07:00Not sure I understand.Not sure I understand.Paul Foxhttps://www.blogger.com/profile/11969759101059066480noreply@blogger.comtag:blogger.com,1999:blog-8336326562741944626.post-170600653500196692011-10-29T13:25:54.614-07:002011-10-29T13:25:54.614-07:00To save you time writing a crude kernel debugger, ...To save you time writing a crude kernel debugger, you might consider using the Joyent method when they ported Linux KVM to SmartOS.<br /><br />* SmartOS host system<br />* Virtualized instance of Ubuntu 11.10<br />* SmartOS dtrace to trace the virtualized instanceotoburbhttps://www.blogger.com/profile/01399613011609624145noreply@blogger.com