From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Luck, Tony" Date: Mon, 30 Jan 2006 23:58:36 +0000 Subject: Re: [PATCH] ia64: avoid broken SAL_CACHE_FLUSH implementations Message-Id: <20060130235836.GA5750@agluck-lia64.sc.intel.com> List-Id: References: <200601301511.57109.bjorn.helgaas@hp.com> In-Reply-To: <200601301511.57109.bjorn.helgaas@hp.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org On Mon, Jan 30, 2006 at 04:51:57PM -0700, Bjorn Helgaas wrote: > On Monday 30 January 2006 16:36, Luck, Tony wrote: > > > If SAL_CACHE_FLUSH drops interrupts, complain about it and fall back to > > > using PAL_CACHE_FLUSH instead. > > > > But PAL_CACHE_FLUSH may not do all that SAL_CACHE_FLUSH does (e.g. if > > the system has caches outside of the scope of PAL). So there is an > > assumption here that only systems where SAL_CACHE_FLUSH is equivalent > > to PAL_CACHE_FLUSH have this bug in their SAL. > > Right. I verified with our firmware guys that in the case of the > rx5670, SAL doesn't do anything extra. So we should be safe there. > > But you're right that in general, SAL may do something extra. > > I'm hoping that the rx5670 is the only shipping box with this problem, > and the error check should point out the problem so firmware for > future boxes can be fixed. > > I thought about also checking for "HP" or "rx5670" somewhere, but > wasn't sure whether the extra effort of grubbing through DMI or > something to find that would be worthwhile. > > > Keith just confirmed that SGI doesn't have this SAL bug, but should I > > be worried about other large ia64 boxes? > > I expect that if other boxes have this problem, they should be seeing > issues, now that we actually *use* SAL_CACHE_FLUSH for the migration > cost measurements. The dropped interrupt should cause pretty obvious > problems. > > (Did you mean to post this to the list? If you meant to but forgot, > you can quote my response.) Doh! Yes, I meant for this one to go to the list. Perhaps the printk(KERN_ERR "SAL: ...); will be enough of a warning in the future to anyone unfortunate enough to have a SAL with this bug and PAL_CACHE_FLUSH != SAL_CACHE_FLUSH. -Tony