The Status of the Preempt-RT Patch Embedded Linux Conference Europe 2017 Sebastian A. Siewior Linutronix GmbH October 24, 2017 Sebastian A. Siewior Linutronix GmbH 1/35 1 Overview 2 The patchqueue 3 Summary Sebastian A. Siewior Linutronix GmbH 2/35 1 Overview 2 The patchqueue 3 Summary Sebastian A. Siewior Linutronix GmbH 3/35 What is PREEMPT-RT A patchset provided for certain kernels Provides realtime functionality Preempts softirq, spinlocks, IRQ-off regions “Is super deterministic, not super fast” Sebastian A. Siewior Linutronix GmbH 4/35 PREEMPT-RT Project was without funds for a few years LF announced RTL Collaborative Project in October 2015 Documentation https://rt.wiki.kernel.org https://wiki.linuxfoundation.org/realtime/start Testing https://ci-rt.linutronix.de Sebastian A. Siewior Linutronix GmbH 5/35 1 Overview 2 The patchqueue 3 Summary Sebastian A. Siewior Linutronix GmbH 6/35 v3.10 450 400 350 300 250 200 150 100 50 0 v3.10.4-rt1 v3.10.6-rt2 v3.10.6-rt3 v3.10.9-rt4 v3.10.9-rt5 v3.10.10-rt6 v3.10.10-rt7 v3.10.14-rt8 v3.10.14-rt9 v3.10.15-rt10 v3.10.15-rt11 v3.10.17-rt12 v3.10.18-rt13 v3.10.18-rt14 all upstream RT only Sebastian A. Siewior Linutronix GmbH 7/35 8/35 Linutronix GmbH v3.12 450 400 350 300 250 200 150 100 50 0 v3.12.0-rt1 v3.12.0-rt2 v3.12.1-rt3 v3.12.1-rt4 v3.12.5-rt5 v3.12.5-rt6 v3.12.5-rt7 v3.12.6-rt8 v3.12.6-rt9 v3.12.8-rt10 v3.12.8-rt11 v3.12.9-rt12 v3.12.9-rt13 v3.12.10-rt14 v3.12.10-rt15 v3.12.11-rt16 v3.12.11-rt17 v3.12.12-rt18 v3.12.12-rt19 v3.12.13-rt20 v3.12.13-rt21 v3.12.14-rt22 v3.12.14-rt23 v3.12.15-rt24 v3.12.15-rt25 all upstream RT only Sebastian A. Siewior v3.14 450 400 350 300 250 200 150 100 50 0 v3.14.0-rt1 v3.14.2-rt2 v3.14.2-rt3 v3.14.3-rt4 v3.14.3-rt5 all upstream RT only Sebastian A. Siewior Linutronix GmbH 9/35 v3.18 450 400 350 300 250 200 150 100 50 0 v3.18.7-rt1 v3.18.7-rt2 v3.18.9-rt3 v3.18.9-rt4 v3.18.9-rt5 v3.18.11-rt6 v3.18.11-rt7 v3.18.13-rt8 v3.18.13-rt9 v3.18.13-rt10 all upstream RT only Sebastian A. Siewior Linutronix GmbH 10/35 v4.0 450 400 350 300 250 200 150 100 50 0 v4.0.4-rt1 v4.0.5-rt2 v4.0.5-rt3 v4.0.5-rt4 v4.0.8-rt5 v4.0.8-rt6 all upstream RT only Sebastian A. Siewior Linutronix GmbH 11/35 v4.1 450 400 350 300 250 200 150 100 50 0 v4.1.2-rt1 v4.1.3-rt2 v4.1.3-rt3 v4.1.5-rt4 v4.1.5-rt5 v4.1.6-rt6 v4.1.7-rt7 v4.1.7-rt8 v4.1.10-rt10 v4.1.10-rt11 v4.1.12-rt12 v4.1.12-rt13 v4.1.13-rt14 v4.1.13-rt15 v4.1.15-rt16 v4.1.15-rt17 all upstream RT only Sebastian A. Siewior Linutronix GmbH 12/35 v4.1 450 400 350 300 250 200 150 100 TI GPIO rework 50 0 v4.1.2-rt1 v4.1.3-rt2 v4.1.3-rt3 v4.1.5-rt4 v4.1.5-rt5 v4.1.6-rt6 v4.1.7-rt7 v4.1.7-rt8 v4.1.10-rt10 v4.1.10-rt11 v4.1.12-rt12 v4.1.12-rt13 v4.1.13-rt14 v4.1.13-rt15 v4.1.15-rt16 v4.1.15-rt17 all upstream RT only Sebastian A. Siewior Linutronix GmbH 13/35 14/35 Linutronix GmbH v4.4 450 400 350 300 250 200 150 100 50 0 v4.4-rc6-rt1 v4.4-rt2 v4.4-rt3 v4.4.1-rt4 v4.4.1-rt5 v4.4.1-rt6 v4.4.2-rt7 v4.4.3-rt8 v4.4.3-rt9 v4.4.4-rt10 v4.4.4-rt11 v4.4.6-rt12 v4.4.6-rt13 v4.4.6-rt14 v4.4.7-rt15 v4.4.7-rt16 v4.4.9-rt17 v4.4.12-rt18 v4.4.12-rt19 all upstream RT only Sebastian A. Siewior 15/35 Linutronix GmbH v4.4 450 400 350 300 250 200 150 100 AT91, SWAIT in TIP 50 0 v4.4-rc6-rt1 v4.4-rt2 v4.4-rt3 v4.4.1-rt4 v4.4.1-rt5 v4.4.1-rt6 v4.4.2-rt7 v4.4.3-rt8 v4.4.3-rt9 v4.4.4-rt10 v4.4.4-rt11 v4.4.6-rt12 v4.4.6-rt13 v4.4.6-rt14 v4.4.7-rt15 v4.4.7-rt16 v4.4.9-rt17 v4.4.12-rt18 v4.4.12-rt19 all upstream RT only Sebastian A. Siewior v4.6 450 400 350 300 250 200 150 100 50 0 v4.6-rc7-rt1 v4.6.1-rt2 v4.6.1-rt3 v4.6.2-rt4 v4.6.2-rt5 v4.6.4-rt6 v4.6.4-rt7 v4.6.4-rt8 v4.6.5-rt9 v4.6.5-rt10 v4.6.7-rt11 v4.6.7-rt12 v4.6.7-rt13 v4.6.7-rt14 all upstream RT only Sebastian A. Siewior Linutronix GmbH 16/35 v4.6 450 400 350 300 250 200 150 100 Timer wheel rework TIP 50 0 v4.6-rc7-rt1 v4.6.1-rt2 v4.6.1-rt3 v4.6.2-rt4 v4.6.2-rt5 v4.6.4-rt6 v4.6.4-rt7 v4.6.4-rt8 v4.6.5-rt9 v4.6.5-rt10 v4.6.7-rt11 v4.6.7-rt12 v4.6.7-rt13 v4.6.7-rt14 all upstream RT only Sebastian A. Siewior Linutronix GmbH 17/35 v4.8 450 400 350 300 250 200 150 100 50 0 v4.8-rt1 v4.8.2-rt2 v4.8.2-rt3 v4.8.6-rt4 v4.8.6-rt5 v4.8.11-rt6 v4.8.11-rt7 v4.8.14-rt8 v4.8.14-rt9 v4.8.15-rt10 all upstream RT only Sebastian A. Siewior Linutronix GmbH 18/35 19/35 Linutronix GmbH v4.9 450 400 350 300 250 200 150 100 50 0 v4.9-rt1 v4.9.4-rt2 v4.9.6-rt3 v4.9.6-rt4 v4.9.9-rt5 v4.9.9-rt6 v4.9.10-rt7 v4.9.11-rt8 v4.9.11-rt9 v4.9.13-rt10 v4.9.13-rt11 v4.9.13-rt12 v4.9.18-rt13 v4.9.18-rt14 v4.9.20-rt15 v4.9.20-rt16 v4.9.27-rt17 v4.9.27-rt18 v4.9.30-rt19 v4.9.30-rt20 v4.9.30-rt21 v4.9.33-rt22 v4.9.33-rt23 all upstream RT only Sebastian A. Siewior 20/35 Linutronix GmbH v4.9 450 400 350 300 250 200 150 100 FUTEX rework More FUTEX 50 0 v4.9-rt1 v4.9.4-rt2 v4.9.6-rt3 v4.9.6-rt4 v4.9.9-rt5 v4.9.9-rt6 v4.9.10-rt7 v4.9.11-rt8 v4.9.11-rt9 v4.9.13-rt10 v4.9.13-rt11 v4.9.13-rt12 v4.9.18-rt13 v4.9.18-rt14 v4.9.20-rt15 v4.9.20-rt16 v4.9.27-rt17 v4.9.27-rt18 v4.9.30-rt19 v4.9.30-rt20 v4.9.30-rt21 v4.9.33-rt22 v4.9.33-rt23 all upstream RT only Sebastian A. Siewior v4.11 450 400 350 300 250 200 150 100 50 0 v4.11.5-rt1 v4.11.7-rt2 v4.11.7-rt3 v4.11.8-rt4 v4.11.8-rt5 v4.11.9-rt6 v4.11.9-rt7 v4.11.12-rt8 v4.11.12-rt9 v4.11.12-rt10 v4.11.12-rt11 v4.11.12-rt12 v4.11.12-rt13 v4.11.12-rt14 v4.11.12-rt15 v4.11.12-rt16 all upstream RT only Sebastian A. Siewior Linutronix GmbH 21/35 v4.11 450 400 350 300 250 200 HR-Timer rework CPU-Hotplug rework 150 Inter-event tracing 100 50 0 v4.11.5-rt1 v4.11.7-rt2 v4.11.7-rt3 v4.11.8-rt4 v4.11.8-rt5 v4.11.9-rt6 v4.11.9-rt7 v4.11.12-rt8 v4.11.12-rt9 v4.11.12-rt10 v4.11.12-rt11 v4.11.12-rt12 v4.11.12-rt13 v4.11.12-rt14 v4.11.12-rt15 v4.11.12-rt16 all upstream RT only Sebastian A. Siewior Linutronix GmbH 22/35 v4.13 450 400 350 300 250 200 150 100 50 0 v4.13.7-rt1 v4.13.7-rt1 all upstream RT only Sebastian A. Siewior Linutronix GmbH 23/35 24/35 Linutronix GmbH Summary 450 400 350 300 250 200 150 100 50 0 v3.10.4-rt1 v3.10.18-rt14 v3.12.0-rt1 v3.12.15-rt25 v3.14.0-rt1 v3.14.3-rt5 v3.18.7-rt1 v3.18.13-rt10 v4.0.4-rt1 v4.0.8-rt6 v4.1.2-rt1 v4.1.15-rt17 v4.4-rc6-rt1 v4.4.12-rt19 v4.6-rc7-rt1 v4.6.7-rt14 v4.8-rt1 v4.8.15-rt10 v4.9-rt1 v4.9.33-rt23 v4.11.5-rt1 v4.11.12-rt16 v4.13.7-rt1 all upstream RT only Sebastian A.