Hi Tracy, On 29 March 2018 15:40, Tracy Smith wrote: > Saw latency spikes on the NXP LS1043 ARM. Single core isolation. Reported it > and they fixed the spikes in their NXP BSP. Not sure if it was pushed to the > community. May want to check the NXP LS1043 community pages and the > cyclictest closed ticket. I don’t recall the bug or fix, but it may have been in > the cyclictest itself. Thanks, I've not been able to find anything on this, just your post on the NXP site. I'm using the latest cyclictest, v1.0.1 Thanks Phil > > On Mar 29, 2018, at 9:26 AM, Phil Edworthy wrote: > >> On 29 March 2018 14:54, Luis Claudio R. Goncalves wrote: > >>> On Thu, Mar 29, 2018 at 07:30:27AM +0000, Phil Edworthy wrote: > >>>> On 28 March 2018 16:32, Clark Williams wrote: > >>>> On Wed, 28 Mar 2018 16:56:27 +0200 John Ogness wrote: > >>>>> On 2018-03-28, Phil Edworthy wrote: > >>>>>>>> I found that cyclictest results vary from one run to another. > > [...] > >>> I did some overnight tests with 100 runs of cyclictest running for 1 > minute. > >>> Stats below were calculated using stats package from > >>> http://web.cs.wpi.edu/~claypool/misc/stats/stats.html > >>> > >>> 1. Interval fixed to 400us, not using --secalign > >>> Min: 20 Avg: 37 Max: 187 (avg of 100xMax is 134) > >>> > >>> 2. Interval fixed to 400us, using --secalign > >>> Min: 20 Avg: 37 Max: 177 (avg of 100xMax is 150) > >>> > >>> 3. Interval increases from 400 to 499, not using --secalign > >>> Min: 20 Avg: 37 Max: 211 (avg of 100xMax is 157) > >>> > >>> 4. Interval increases from 400 to 499, using --secalign > >>> Min: 20 Avg: 37 Max: 202 (avg of 100xMax is 157) > >>> > >>> While --secalign may provide more consistent results, it appears > >>> that it is not as good at identifying the worst case latency. > >>> It appears that testing different intervals is much better at > >>> identifying the worst case latency. > >> > >> Have you used the hwlat ftrace tracer or hwlatdetector.py from > >> rt-tests in order to verify if your system have SMI-induced latency > >> spikes? That may not be part of the problem described here, but > >> spurious SMI spikes could account to some of the discrepancies. > > This is on ARM, so no SMI. There's no BIOS, nothing like that. > > > > Thanks > > Phil > > -- > > To unsubscribe from this list: send the line "unsubscribe > > linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx > > More majordomo info at http://vger.kernel.org/majordomo-info.html ��.n��������+%������w��{.n�����{�����ǫ���ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
