From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philippe Gerum In-Reply-To: <455E025B.5030906@domain.hid> References: <1163784779.4980.47.camel@domain.hid> <455E025B.5030906@domain.hid> Content-Type: text/plain Date: Fri, 17 Nov 2006 20:05:15 +0100 Message-Id: <1163790315.4980.73.camel@domain.hid> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [Xenomai-core] Re: XENO_OPT_DEBUG impact (was: exception 768) Reply-To: rpm@xenomai.org List-Id: "Xenomai life and development \(bug reports, patches, discussions\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Jan Kiszka Cc: xenomai-core On Fri, 2006-11-17 at 19:41 +0100, Jan Kiszka wrote: > Philippe Gerum wrote: > > ... > > Disable CONFIG_XENO_OPT_DEBUG from your kernel configuration, this is > > the source of the PTE misses you are seeing now on ppc. This is not to > > say that those errors are normal, and this issue still remains to be > > fixed, but unless you want to debug the Xenomai nucleus, you don't need > > this option on (additionally, it adds a large overhead which translates > > in significantly augmented jitter). > > CONFIG_XENO_OPT_DEBUG should not add large jitters - that's what e.g. CONFIG_SMP + CONFIG_XENO_OPT_DEBUG instruments the nucleus lock macros with consistency and latency tracking code. This does not come for free, even if an order of magnitude less than checking the queues. > CONFIG_XENO_OPT_DEBUG_QUEUES is now for. > > I'm currently seeing two potential "misuses" of the common switch: > > - the posix skin (Gilles, how heavy-weighted are those checks?) > => CONFIG_XENO_OPT_DEBUG_POSIX > > - CONFIG_XENO_SPINLOCK_DEBUG => CONFIG_XENO_OPT_DEBUG_SPINLOCK > > Both should be explicitly controllable in Kconfig. > Nack for CONFIG_XENO_OPT_DEBUG_SPINLOCK. Most of the issue we tracked with Gilles regarding the domain migration code had side-effects on the nucleus lock. So having CONFIG_XENO_OPT_DEBUG enabled for identifying internal state weirdnesses - like those triggered by migration bugs - implies enabling the spinlock watchdogs too. > Gilles, is CONFIG_XENO_OPT_DEBUG_BHEAP used in any way? Doesn't seem so. > > Jan > -- Philippe.