Interesting notes from LKML and openipmi. An estimate was that kipmid hogs 10W from a 70W server.
//Peter ----- Forwarded message from Bela Lubkin <[email protected]> ----- From: Bela Lubkin <[email protected]> To: 'Corey Minyard' <[email protected]>, Randy Dunlap <[email protected]> CC: "[email protected]" <[email protected]>, "Kok, Auke" <[email protected]>, Arjan van de Ven <[email protected]>, "[email protected]" <[email protected]>, lkml <[email protected]> Subject: RE: [Openipmi-developer] [Discuss] [PATCH] ipmi: use round_jiffies on timers to reduce timer overhead/wakeups Date: Wed, 21 Oct 2009 16:46:41 -0700 Corey Minyard & Randy Dunlap wrote: Randy>> From what I recall (probably 2 years ago), [older] ipmi hardware Randy>> does not generate event interrupts, so it has to be polled. Randy>> Randy>> Corey, can you elaborate on this? Corey> Certainly. Yes, some (probably most) IPMI hardware does not use Corey> interrupts, and unfortunately, it's not just older machines. Corey> The driver used to poll more slowly, but in many cases the Corey> performance was unacceptable. Corey> Corey> kipmid is only started if the hardware doesn't support Corey> interrupts, so only users with sub-standard hardware have to Corey> suffer with this problem. Regrettably, of the "big three" in the "PC Server" world, only HP's iLO2 BMC supports interrupts. Dell's DRAC4 & 5 don't, IBM's ASM, RSA, etc. don't. Also (at least out of a sample of one) SuperMicro also doesn't have an interrupt. They also have all settled on the KCS interface, which dribbles one character through per non-interrupt. So sad. Dell's DRAC3 had a BT BMC which transferred whole IPMI packets via DMA _and_ had an interrupt. HP's ancient SMIC equipment also had an interrupt (but that's also char-by-char, and their current KCS has an interrupt, so at least they haven't regressed). I've guessed that some chip vendor must have come out with a Really Cheep KCS implementation and drove every other implementation out of the market. :-( I've heard rumors that some current Sun hardware has BT. >Bela<-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ ----- End forwarded message ----- -- coreboot mailing list: [email protected] http://www.coreboot.org/mailman/listinfo/coreboot
