Hi, It's a while since the last attempt by Paul to get simple wait ready for mainline [1]. At the last realtime workshop it was discussed how the swait implementation could be made preempt aware. Peter posted an untested version of it here [2].
In order to test it, I used Paul's two patches which makes completion and rcu using swait instead of wait. Some small renamings were necessary to get it working, e.g. s/swait_head/swait_queue_head/. My test system didn't crash or showed any obvious defects, so I decided to apply some benchmarks utilizing mmtests. I have picked some random tests (kernbench aim9 vmr-stream ebizz), which didn't require a lot of tinker around to get them running. The results are here: baseline: v4.2-rc5-22-ged8bbba http://monom.org/mmtests-swait-peterz-v1/ I don't think the numbers are trustworthy yet. Mabye one could read it as it doesn't explode and the numbers aren't to far away from baseline. I need to figure out which tests are fitting for these patches and what are the 'right' parameters for them. Sebastian had some comments on Peter's patch. I haven't addressed them yet [3]. cheers, daniel [1] https://lwn.net/Articles/616857/ [2] http://www.spinics.net/lists/linux-rt-users/msg12703.html [3] https://www.mail-archive.com/[email protected]/msg832142.html Paul Gortmaker (2): sched/completion: convert completions to use simple wait queues rcu: use simple wait queues where possible in rcutree Peter Zijlstra (1): KVM: use simple waitqueue for vcpu->wq include/linux/completion.h | 8 +-- include/linux/swait.h | 172 +++++++++++++++++++++++++++++++++++++++++++++ kernel/rcu/tree.c | 13 ++-- kernel/rcu/tree.h | 6 +- kernel/rcu/tree_plugin.h | 18 ++--- kernel/sched/Makefile | 2 +- kernel/sched/completion.c | 32 ++++----- kernel/sched/swait.c | 122 ++++++++++++++++++++++++++++++++ 8 files changed, 334 insertions(+), 39 deletions(-) create mode 100644 include/linux/swait.h create mode 100644 kernel/sched/swait.c -- 2.4.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
