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Wyatt IV" Cc: John Ogness , Clark Williams , jlelli@redhat.com, Derek Barbosa , "John B. Wyatt IV" , LKML , linux-rt-users Subject: Re: NMI Reported with console_blast.sh Message-ID: References: <87v86yc88b.fsf@jogness.linutronix.de> <87a5o8j9gp.fsf@jogness.linutronix.de> Precedence: bulk X-Mailing-List: linux-rt-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Thu 2024-02-29 12:15:30, Petr Mladek wrote: > On Thu 2024-02-22 00:21:19, John B. Wyatt IV wrote: > > On Mon, Feb 12, 2024 at 04:23:04PM -0500, John B. Wyatt IV wrote: > > > > > > Red Hat's conservers are having an issue with the machine I was testing > > > on. It may take me a while to get back to you with more test results. > > > > > > > Found a work-around with conserver. I was able to follow up on the printk-caller > > info you requested. > > > > I found 2 additional NMIs for a total of 3. Number 2 is very > > large-please feel free to let me know what specific information you > > wanted if it was unnecessary. [...] > > Compared to the two NMIs with throughput-performance (no preemption) > > > > > > cpus=0 > > .runnable_avg : 3072 > > kthread (kernel/kthread.c:388) > > .util_est_enqueued : 0 > > stack:0 pid:1733 tgid:1733 ppid:2 flags:0x00004000 > > .min_vruntime : 2084315.290254 > > .removed.load_avg : 0 > > .avg_vruntime : 2084315.290254 > > console_blast.s 3497 34770.405603 N 34773.405603 3.000000 34764.898340 4 120 > > .util_avg : 1024 > > .util_avg : 1024 > > It looks like messages from more (many) CPUs are mixed. I guess that they > are printed by print_cfs_rq(). But the order looks random. > > Also I wonder why it is printed from NMI context. Maybe, it is from > some perf event, similar to hardlockup detector? I have realized that we most likely see only small part of the mixed output. I wonder if it is because it is printed from the emergency context. Here the messages are flushed when leaving the context and many might be lost. Best Regards, Petr