From mboxrd@z Thu Jan 1 00:00:00 1970 From: pavel@ucw.cz (Pavel Machek) Date: Fri, 19 Jul 2019 15:59:32 +0200 Subject: [cip-dev] [OBSOLETE?] CONFIG_PREEMPT_RT_FULL config parameter in 4.19?! In-Reply-To: References: Message-ID: <20190719135932.GA23951@amd> To: cip-dev@lists.cip-project.org List-Id: cip-dev.lists.cip-project.org Hi! > I started my own investigation about RT kernels, namely 4.19. I > proceed very carefully over the kernel config parameters... BUt the > last one I inspected today got me nowhere!? > > Seems, that the following config parameters are obsolete in 4.19: > CONFIG_PREEMPT_RT_FULL > > This one (CONFIG_PREEMPT_RT_FULL) is still present in 4.4 . > > [vuser at fedora30-ssd kernel-config]$ cat CONFIG-4.4.120-rt-bbb | grep PREEMPT > CONFIG_PREEMPT_RCU=y > CONFIG_PREEMPT=y > CONFIG_PREEMPT_RT_BASE=y > CONFIG_HAVE_PREEMPT_LAZY=y > CONFIG_PREEMPT_LAZY=y > # CONFIG_PREEMPT_NONE is not set > # CONFIG_PREEMPT_VOLUNTARY is not set > # CONFIG_PREEMPT__LL is not set > # CONFIG_PREEMPT_RTB is not set > CONFIG_PREEMPT_RT_FULL=y <<======= Obsolete in 4.19 ? > CONFIG_PREEMPT_COUNT=y > CONFIG_DEBUG_PREEMPT=y > [vuser at fedora30-ssd kernel-config]$ > > What I should do to maintain RT-kernel-4.19? It is obvious, I must/need to set: > CONFIG_PREEMPT=y Are you sure you have your kernel patched with -rt patches? CONFIG_PREEMPT_RT_FULL=y was still needed in 4.19, AFAICT. Note that not every piece of hardware has suitable characteristics for realtime / low latencies. Best regards, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 181 bytes Desc: Digital signature URL: