Messages in this thread |  | | From | Lihao Liang <> | Date | Sat, 27 Jan 2018 09:57:03 +0000 | Subject | Re: [PATCH RFC 00/16] A new RCU implementation based on a fast consensus protocol |
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On Sat, Jan 27, 2018 at 7:57 AM, Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote: > On Sat, Jan 27, 2018 at 07:22:27AM +0000, Lihao Liang wrote: >> On Thu, Jan 25, 2018 at 5:53 AM, Paul E. McKenney >> <paulmck@linux.vnet.ibm.com> wrote: >> > On Tue, Jan 23, 2018 at 03:59:25PM +0800, lianglihao@huawei.com wrote: >> >> From: Lihao Liang <lianglihao@huawei.com> >> >> >> >> Dear Paul, >> >> >> >> This patch set implements a preemptive version of RCU (PRCU) based on the following paper: >> >> >> >> Fast Consensus Using Bounded Staleness for Scalable Read-mostly Synchronization. >> >> Haibo Chen, Heng Zhang, Ran Liu, Binyu Zang, and Haibing Guan. >> >> IEEE Transactions on Parallel and Distributed Systems (TPDS), 2016. >> >> https://dl.acm.org/citation.cfm?id=3024114.3024143 >> >> >> >> We have also added preliminary callback-handling support. Thus, the current version >> >> provides APIs prcu_read_lock(), prcu_read_unlock(), synchronize_prcu(), call_prcu(), >> >> and prcu_barrier(). >> >> >> >> This is an experimental patch, so it would be good to have some feedback. >> >> >> >> Known shortcoming is that the grace-period version is incremented in synchronize_prcu(). >> >> If call_prcu() or prcu_barrier() is called but there is no synchronized_prcu() invoked, >> >> callbacks cannot be invoked. Later version should address this issue, e.g. adding a >> >> grace-period expedition mechanism. Others include to use a a hierarchical structure, >> >> taking into account the NUMA topology, to send IPI in synchronize_prcu(). >> >> >> >> We have tested the implementation using rcutorture on both an x86 and ARM64 machine. >> >> PRCU passed 1h and 3h tests on all the newly added config files except PRCU07 reported BUG >> >> in a 1h run. >> >> >> >> [ 1593.604201] ---[ end trace b3bae911bec86152 ]--- >> >> [ 1594.629450] prcu-torture:torture_onoff task: offlining 14 >> >> [ 1594.755553] smpboot: CPU 14 is now offline >> >> [ 1594.757732] prcu-torture:torture_onoff task: offlined 14 >> >> [ 1597.765149] prcu-torture:torture_onoff task: onlining 11 >> >> [ 1597.766795] smpboot: Booting Node 0 Processor 11 APIC 0xb >> >> [ 1597.804102] prcu-torture:torture_onoff task: onlined 11 >> >> [ 1599.365098] prcu-torture: rtc: ffffffffb0277b90 ver: 66358 tfle: 0 rta: 66358 rtaf: 0 >> >> rtf: 66349 rtmbe: 0 rtbe: 1 rtbke: 0 rtbre: 0 rtbf: 0 rtb: 0 nt: 2233418 >> >> onoff: 191/191:199/199 34,199:59,5102 10403:0 (HZ=1000) barrier: 188/189:1 cbflood: 225 >> >> [ 1599.367946] prcu-torture: !!! >> >> [ 1599.367966] ------------[ cut here ]------------ >> > >> > The "rtbe: 1" indicates that your implementation of prcu_barrier() >> > failed to wait for all preceding call_prcu() callbacks to be invoked. >> > >> > Does the immediately following "Reader Pipe:" list have any but the >> > first two numbers non-zero? >> >> Yes. > > If the third or subsequent numbers are non-zero, that would indicate > too-short grace periods. This would be a critical bug in PRCU. > >> >> We have also compared PRCU with TREE RCU using rcuperf with gp_exp set to true, that is >> >> synchronize_rcu_expedited was tested. >> >> >> >> The rcuperf results are as follows (average grace-period duration in ms of ten 10min runs): >> >> >> >> 16*Intel Xeon CPU@2.4GHz, 16GB memory, Ubuntu Linux 3.13.0-47-generic >> >> >> >> CPUs 2 4 8 12 15 16 >> >> PRCU 0.14 1.07 4.15 8.02 10.79 15.16 >> >> TREE 49.30 104.75 277.55 390.82 620.82 1381.54 >> >> >> >> 64*Cortex-A72 CPU@2.4GHz, 130GB memory, Ubuntu Linux 4.10.0-21.23-generic >> >> >> >> CPUs 2 4 8 16 32 48 63 64 >> >> PRCU 0.23 19.69 38.28 63.21 95.41 167.18 252.01 1841.44 >> >> TREE 416.73 901.89 1060.86 743.00 920.66 1325.21 1646.20 23806.27 >> > >> > Well, at the very least, this is a bug report on either expedited RCU >> > grace-period latency or on rcuperf's measurements, and thank you for that. >> > I will look into this. In the meantime, could you please let me know >> > exactly how you invoked rcuperf? >> >> We used the following command to invoke rcuperf: >> >> sudo ./kvm.sh --torture rcuperf --duration 10 --configs 10*TREE >> >> The actual script run-rcuperf.sh to run the experiments can be found >> in the following email of this patch series: >> >> [PATCH RFC 15/16] rcutorture: Add scripts to run experiments >> >> Please let us know how it goes. > > Will do! > > As I said before, at the very least you have identified a performance bug > in RCU expedited grace periods. >
I should add that we also tested the normal synchronize_rcu() on the same x86 machine, and the rcuperf figures were about 10 times slower than those of synchronize_rcu_expedited().
Is this expected for synchronize_rcu()?
Best, Lihao.
> Thanx, Paul > >> Many thanks, >> Lihao. >> >> > I have a few comments on some of your patches based on a quick scan >> > through them. >> > >> > Thanx, Paul >> > >> >> Best wishes, >> >> Lihao. >> >> >> >> >> >> Lihao Liang (15): >> >> rcutorture: Add PRCU rcu_torture_ops >> >> rcutorture: Add PRCU test config files >> >> rcuperf: Add PRCU rcu_perf_ops >> >> rcuperf: Add PRCU test config files >> >> rcuperf: Set gp_exp to true for tests to run >> >> prcu: Implement call_prcu() API >> >> prcu: Implement PRCU callback processing >> >> prcu: Implement prcu_barrier() API >> >> rcutorture: Test call_prcu() and prcu_barrier() >> >> rcutorture: Add basic ARM64 support to run scripts >> >> prcu: Add PRCU Kconfig parameter >> >> prcu: Comment source code >> >> rcuperf: Add config files with various CONFIG_NR_CPUS >> >> rcutorture: Add scripts to run experiments >> >> Add GPLv2 license >> >> >> >> Heng Zhang (1): >> >> prcu: Add PRCU implementation >> >> >> >> include/linux/interrupt.h | 3 + >> >> include/linux/prcu.h | 122 +++++ >> >> include/linux/rcupdate.h | 1 + >> >> init/Kconfig | 7 + >> >> init/main.c | 2 + >> >> kernel/rcu/Makefile | 1 + >> >> kernel/rcu/prcu.c | 497 +++++++++++++++++++++ >> >> kernel/rcu/rcuperf.c | 33 +- >> >> kernel/rcu/rcutorture.c | 40 +- >> >> kernel/rcu/tree.c | 1 + >> >> kernel/sched/core.c | 2 + >> >> kernel/time/timer.c | 2 + >> >> kvm.sh | 452 +++++++++++++++++++ >> >> run-rcuperf.sh | 26 ++ >> >> .../testing/selftests/rcutorture/bin/functions.sh | 17 +- >> >> .../selftests/rcutorture/configs/rcu/CFLIST | 5 + >> >> .../selftests/rcutorture/configs/rcu/PRCU02 | 27 ++ >> >> .../selftests/rcutorture/configs/rcu/PRCU02.boot | 1 + >> >> .../selftests/rcutorture/configs/rcu/PRCU03 | 23 + >> >> .../selftests/rcutorture/configs/rcu/PRCU03.boot | 2 + >> >> .../selftests/rcutorture/configs/rcu/PRCU06 | 26 ++ >> >> .../selftests/rcutorture/configs/rcu/PRCU06.boot | 5 + >> >> .../selftests/rcutorture/configs/rcu/PRCU07 | 25 ++ >> >> .../selftests/rcutorture/configs/rcu/PRCU07.boot | 2 + >> >> .../selftests/rcutorture/configs/rcu/PRCU09 | 19 + >> >> .../selftests/rcutorture/configs/rcu/PRCU09.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/CFLIST | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU | 20 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU-12 | 21 + >> >> .../rcutorture/configs/rcuperf/PRCU-12.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU-14 | 21 + >> >> .../rcutorture/configs/rcuperf/PRCU-14.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU-15 | 21 + >> >> .../rcutorture/configs/rcuperf/PRCU-15.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU-16 | 21 + >> >> .../rcutorture/configs/rcuperf/PRCU-16.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU-2 | 21 + >> >> .../rcutorture/configs/rcuperf/PRCU-2.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU-32 | 21 + >> >> .../rcutorture/configs/rcuperf/PRCU-32.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU-4 | 21 + >> >> .../rcutorture/configs/rcuperf/PRCU-4.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU-48 | 21 + >> >> .../rcutorture/configs/rcuperf/PRCU-48.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU-56 | 21 + >> >> .../rcutorture/configs/rcuperf/PRCU-56.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU-60 | 21 + >> >> .../rcutorture/configs/rcuperf/PRCU-60.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU-62 | 21 + >> >> .../rcutorture/configs/rcuperf/PRCU-62.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU-64 | 21 + >> >> .../rcutorture/configs/rcuperf/PRCU-64.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU-8 | 21 + >> >> .../rcutorture/configs/rcuperf/PRCU-8.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/PRCU.boot | 1 + >> >> .../selftests/rcutorture/configs/rcuperf/TREE-12 | 21 + >> >> .../selftests/rcutorture/configs/rcuperf/TREE-14 | 21 + >> >> .../selftests/rcutorture/configs/rcuperf/TREE-15 | 21 + >> >> .../selftests/rcutorture/configs/rcuperf/TREE-16 | 21 + >> >> .../selftests/rcutorture/configs/rcuperf/TREE-2 | 21 + >> >> .../selftests/rcutorture/configs/rcuperf/TREE-32 | 21 + >> >> .../selftests/rcutorture/configs/rcuperf/TREE-4 | 21 + >> >> .../selftests/rcutorture/configs/rcuperf/TREE-48 | 21 + >> >> .../selftests/rcutorture/configs/rcuperf/TREE-56 | 21 + >> >> .../selftests/rcutorture/configs/rcuperf/TREE-60 | 21 + >> >> .../selftests/rcutorture/configs/rcuperf/TREE-62 | 21 + >> >> .../selftests/rcutorture/configs/rcuperf/TREE-64 | 21 + >> >> .../selftests/rcutorture/configs/rcuperf/TREE-8 | 21 + >> >> 68 files changed, 1918 insertions(+), 5 deletions(-) >> >> create mode 100644 include/linux/prcu.h >> >> create mode 100644 kernel/rcu/prcu.c >> >> create mode 100755 kvm.sh >> >> create mode 100755 run-rcuperf.sh >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/PRCU02 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/PRCU02.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/PRCU03 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/PRCU03.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/PRCU06 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/PRCU06.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/PRCU07 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/PRCU07.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/PRCU09 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcu/PRCU09.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-12 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-12.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-14 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-14.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-15 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-15.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-16 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-16.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-2 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-2.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-32 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-32.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-4 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-4.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-48 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-48.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-56 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-56.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-60 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-60.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-62 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-62.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-64 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-64.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-8 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU-8.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/PRCU.boot >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/TREE-12 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/TREE-14 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/TREE-15 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/TREE-16 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/TREE-2 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/TREE-32 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/TREE-4 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/TREE-48 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/TREE-56 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/TREE-60 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/TREE-62 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/TREE-64 >> >> create mode 100644 tools/testing/selftests/rcutorture/configs/rcuperf/TREE-8 >> >> >> >> -- >> >> 2.14.1.729.g59c0ea183 >> >> >> > >> >
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