Hi! On Marvell Kirkwood at 1.2Ghz and 3.2.51-rt72 kernel I have slightly better results: --- with hackbench: root@debian:~/rt-tests# ./cyclictest -l 10000 -i 1000 -n -p 80 -q T: 0 (10268) P:80 I:1000 C: 10000 Min: 16 Act: 29 Avg: 29 Max: 46 --- w/o hackbench: root@debian:~/rt-tests# ./cyclictest -l 10000 -i 1000 -n -p 80 -q T: 0 (12686) P:80 I:1000 C: 10000 Min: 5 Act: 6 Avg: 6 Max: 22 -- .config: CONFIG_TICK_ONESHOT=y # CONFIG_NO_HZ is not set CONFIG_HIGH_RES_TIMERS=y # CONFIG_CPU_IDLE is not set Try to play with: # CONFIG_PM_RUNTIME is not set # CONFIG_ARM_CPU_SUSPEND is not set Best wishes, Dmitry. 2013/11/26 Stefan Roese <stefan.roese@xxxxxxxxx> > > Hi! > > I'm running cylictest on a OMAP3530 target board and am a bit > astonished about the results. Especially that the latency values > are better on a system with system load (hackbench) than on one > without system load. Here the values I get: > > With system load (hackbench): > ----------------------------- > # ./cyclictest -l 10000 -i 1000 -n -p 80 -q > # /dev/cpu_dma_latency set to 0us > T: 0 ( 1853) P:80 I:1000 C: 10000 Min: 36 Act: 156 Avg: 154 Max: > 244 > > Idle system: > ------------ > # ./cyclictest -l 10000 -i 1000 -n -p 80 -q > # /dev/cpu_dma_latency set to 0us > T: 0 ( 2332) P:80 I:1000 C: 10000 Min: 81 Act: 530 Avg: 484 Max: > 602 > > > Some details to my test/system setup: > - Linux v3.8.13 > - preempt-rt patch 3.8.13-rt14 > - HW: TI OMAP3530 CM_T35 board > - Latest cyclictest from rt-tests git repository > > > I might have misconfigured the system. So here some extracts from > my .config: > > ... > CONFIG_TICK_ONESHOT=y > CONFIG_NO_HZ=y > CONFIG_HIGH_RES_TIMERS=y > ... > # CONFIG_CPU_FREQ is not set > # CONFIG_CPU_IDLE is not set > # CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED is not set > ... > CONFIG_PREEMPT_RT_FULL=y > ... > > With CONFIG_NO_HZ disabled I get slightly better results: > > With system load (hackbench): > ----------------------------- > # ./cyclictest -l 10000 -i 1000 -n -p 80 -q > # /dev/cpu_dma_latency set to 0us > T: 0 ( 1840) P:80 I:1000 C: 10000 Min: 30 Act: 153 Avg: 154 Max: > 238 > > Idle system: > ------------- > # ./cyclictest -l 10000 -i 1000 -n -p 80 -q > # /dev/cpu_dma_latency set to 0us > T: 0 ( 1371) P:80 I:1000 C: 10000 Min: 40 Act: 465 Avg: 435 Max: > 502 > > > Any ideas/explanations are really appreciated. > > Thanks, > Stefan -- 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
