Return-Path: MIME-Version: 1.0 In-Reply-To: <20180201190150.GA868@jcartwri.amer.corp.natinst.com> References: <20180201190150.GA868@jcartwri.amer.corp.natinst.com> From: Mirza Krak Date: Wed, 7 Feb 2018 10:34:02 +0100 Message-ID: Subject: Re: High CPU load when using USB Bluetooth on 4.14.15-rt13 kernel To: Julia Cartwright Cc: linux-bluetooth@vger.kernel.org, Marcel Holtmann , linux-rt-users@vger.kernel.org Content-Type: text/plain; charset="UTF-8" List-ID: On 1 February 2018 at 20:01, Julia Cartwright wrote: > On Thu, Feb 01, 2018 at 10:58:28AM +0100, Mirza Krak wrote: >> Hi. > > Hello Mirza. > > [..] >> I have tried running a 4.14.15 vanilla kernel, and this does not have >> this problem which means that it is the following combo >> >> RT + USB Bluetooth >> >> That seem to the problem. >> >> Before I start digging deep in to the stacks I wanted to post my >> problem to the community to see if someone is having a similar problem >> on a different hardware or if you have any pointers on how to further >> debug this. > > One suggestion I would have would be to re-do your testing on mainline > v4.14.15 booted with the 'threadirqs' kernel command line parameter. > > The reason being that without this option, interrupts aren't threaded in > mainline, so it very well could be that your hardware is still > misbehaving, however it's execution time just isn't being accounted for > in the same way. Thank you for the hint. Adding "threadirq" on the mainline kernel exposed the CPU load and I guess that this is not a RT problem then. Thank you once again. --=20 Med V=C3=A4nliga H=C3=A4lsningar / Best Regards Mirza Krak