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Date: Thu, 06 Dec 2007 10:27:09 -0800 From: Roland Dreier <rdreier@...co.com> To: Arnd Bergmann <arnd@...db.de> Cc: linuxppc-dev@...abs.org, Joachim Fenkes <fenkes@...ibm.com>, LKML <linux-kernel@...r.kernel.org>, "OF-General" <general@...ts.openfabrics.org>, Roland Dreier <rolandd@...co.com>, "OF-EWG" <ewg@...ts.openfabrics.org>, Stefan Roscher <stefan.roscher@...ibm.com>, Christoph Raisch <raisch@...ibm.com>, Marcus Eder <meder@...ibm.com> Subject: Re: [PATCH] IB/ehca: Serialize HCA-related hCalls on POWER5 > > + ehca_lock_hcalls = !(cur_cpu_spec->cpu_user_features > > + & PPC_FEATURE_ARCH_2_05); > We already talked about this yesterday, but I still feel that checking the > instruction set of the CPU should not be used to determine whether a > specific device driver implementation is used int hypervisor. I had the same reaction... is testing cpu_user_features really the best way to detect this issue? I'll hold off applying this for a few days so you guys can decide the best thing to do. We'll definitely get some fix into 2.6.24 but we have time to make a good decision. > Regarding the performance problem, have you checked whether converting all > your spin_lock_irqsave to spin_lock/spin_lock_irq improves your performance > on the older machines? Maybe it's already fast enough that way. It does seem that the only places that the hcall_lock is taken also use msleep, so they must always be in process context. So you can safely just use spin_lock(), right? - R. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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