On Thu, Sep 5, 2013 at 3:25 PM, Joe Talbott <joe.talb...@canonical.com> wrote: > On Thu, Sep 05, 2013 at 03:01:37PM +0300, Alberto Mardegan wrote: >> On 09/05/2013 12:42 PM, Colin Ian King wrote: >> > On 05/09/13 10:33, Colin Ian King wrote: >> >> On 05/09/13 10:23, Evan Dandrea wrote: >> >>> Stuart Langridge brought up an interesting idea for this on IRC, which >> >>> I'm copying here rather than having more side discussions: >> [...] >> >> Oops, I should have read the whole thread before posting my previous >> e-mail. :-) >> >> > Anyhow, I still think myAppIsRunning() is open to abuse as it will in >> > time be lavishly added to all sorts of tight loops that suck CPU, which >> > just adds more overhead on the long run. >> >> Well, if we don't have a myAppIsRunning() API, apps can simply busy-loop >> whenever they want, so I don't see much harm in adding this API. >> We could also protect it with apparmor, so that the usage of this API >> must be explicitly declared in the application's manifest file (and then >> we could question whether the app has any reason to use it). >> >> Note however that this would still solve the issue of detecting apps who >> use too much CPU time because of some bugs, which I think was the >> original goal. > > Would a watchdog sort of timer work better here? One where the OS sends > a signal to a high CPU usage app and if the app doesn't respond to the > signal we have a better clue that something is amiss. >
Hmmm, effectively extending the ANR approach to non-UI bits. That is interesting idea. Admittedly, an app could work around that, too, but hey :) Further extending on the idea: Whenever we identify a process that is using too much CPU over a certain period of time, we start ptrac'ing it and send over a SIGXCPU. If the process hasn't setup a signal handler for that signal and we find out (waitpid and friends), we can assume that the process is either not behaving in the Ubuntu way _or_ something is wrong and we SIGKILL. Alternatively, we could use SIGUSR1/SIGUSR2. Makes sense? Thomas > Thanks, > Joe > > -- > Mailing list: https://launchpad.net/~ubuntu-phone > Post to : ubuntu-phone@lists.launchpad.net > Unsubscribe : https://launchpad.net/~ubuntu-phone > More help : https://help.launchpad.net/ListHelp -- Mailing list: https://launchpad.net/~ubuntu-phone Post to : ubuntu-phone@lists.launchpad.net Unsubscribe : https://launchpad.net/~ubuntu-phone More help : https://help.launchpad.net/ListHelp
