On Tue 2011-08-09 00:09:42, Rafael J. Wysocki wrote: > On Monday, August 08, 2011, Pavel Machek wrote: > > Hi! > > > > > > > > > Thanks for the nice pointer. I checked dynamic debug. It's really a good debug tool. > > > > > > > With the dynamic debug: > > > > > > > 1) user need write a user space parser to process the syslog output; > > > > > > > 2) Our testing scenario is we leave the mobile for at least hours. Then, check its status. > > > > > > > No serial console available during the testing. One is because console would be suspended, > > > > > > > and the other is serial console connecting with spi or HSU devices would consume power. These > > > > > > > devices are powered off at suspend-2-ram. > > ... > > > Not in the case described by Yanmin. > > > > Really? I see the description above. > > > > Yes, they'd need to set up syslog to only log >= KERN_ERR, then parse > > the (small) results. Even hours worth of suspends should not cause > > _that_ many errors. > > > > Serial console is irrelevant. You need live machine to dump dmesg, but > > again, you need live machine to access debugfs, too. > > This sounds like substantial overhead to collect statistics that we can > collect at a much lower cost in the kernel. That's always the case, right? Everyone wants different subsets of syslog, and doing selection in kernel is always lowest overhead. > The patch isn't very intrusive and rather straightforward. No, it is not _too_ bad; but 1) the code stays there when not debugging 2) different users want different syslog subsets. Putting all the "interesting" subsets into /sys/debug/my_syslog_subset just does not seem like a way to go. (If anything simpler could be done to help debugging, like generating udev event on each failed suspend, so that can trigger their processing, I guess that would be acceptable.) Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
