From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <504FAAE6.5010701@xenomai.org> Date: Tue, 11 Sep 2012 23:19:34 +0200 From: Gilles Chanteperdrix MIME-Version: 1.0 References: <504EC598.7050005@ebus.com> <504F8F55.9080006@xenomai.org> In-Reply-To: <504F8F55.9080006@xenomai.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Subject: Re: [Xenomai] Interpreting I-pipe trace List-Id: Discussions about the Xenomai project List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Doug Brunner Cc: xenomai@xenomai.org On 09/11/2012 09:21 PM, Gilles Chanteperdrix wrote: > On 09/11/2012 07:01 AM, Doug Brunner wrote: > >> While running my latency testing earlier I saw some rather high >> worst-case latencies (~70us) compared to average case (~14us), so I ran >> again with I-pipe tracing enabled. However, I'm not sure what to make of >> the results. >> >> My worst case involves an IRQ (common_interrupt appears in the trace >> with user value 0xFFFFFFC4) and the wiki page talks about being able to >> translate the user value 0xFFFFFFF4 into IRQ 11 but doesn't elaborate on >> how this correspondence works. I'm not horribly concerned since it's a >> delay of 53 us on a rather slow processor (Geode LX800) but it would be >> nice to know what interrupt is taking so long. > > > You may also want to apply the following patch for SMI on Geode LX, and > enable CONFIG_XENO_HW_SMI_WORKAROUND. You can remove the '#if 0', if you > do not use PCI. You have to pass cs5536.msr=1 to avoid using PCI registers access (which use SMIs) in the IDE driver. -- Gilles.