On Friday 21 October 2005 13:47, Serge Goodenko wrote: > How can I increase the resolution of UML kernel timer? Elaborate on what you mean. You show being a kernel hacker, and I need to know if you want to increase the resolution for jiffies (i.e. you must surely increase HZ in UML) or with some other API.
For instance, IIRC the standard kernel has support for interpolators, which is used for gettimeofday(). To use that, you need an external source. And maybe UML implements (or this could be done) a "source" using host gettimeofday(). After doing that, you're only limited by host gettimeofday() precision, and to increase that you may: > Should I apply any patches to host kernel (like HRT or ktimers) or what? But first UML must use host gettimeofday(). > I need to use higher than standard jiffies resolution (10ms) in kernel > network code. Don't remember where, but at least you can try increasing HZ for UML (include/asm-um/param.h). That is reasonable until 1000. For an host, it has been suggested that 10000 would work, but don't know for the guest. Also, HZ (i.e. the timer interrupt) is implemented using signals (i.e. alarm()), which are both slow and not precise (no more than host jiffies). > Using 2.6.13 UML kernel, 2.6.8 host kernel Don't know for the host kernel which support it gives. -- Inform me of my mistakes, so I can keep imitating Homer Simpson's "Doh!". Paolo Giarrusso, aka Blaisorblade (Skype ID "PaoloGiarrusso", ICQ 215621894) http://www.user-mode-linux.org/~blaisorblade ___________________________________ Yahoo! Mail: gratis 1GB per i messaggi e allegati da 10MB http://mail.yahoo.it ------------------------------------------------------- This SF.Net email is sponsored by: Power Architecture Resource Center: Free content, downloads, discussions, and more. http://solutions.newsforge.com/ibmarch.tmpl _______________________________________________ User-mode-linux-user mailing list User-mode-linux-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-user
