[RFC PATCH v2 2/2] scheduler: add scheduler level for clusters
Song Bao Hua (Barry Song)
song.bao.hua at hisilicon.com
Wed Dec 2 05:48:06 EST 2020
> -----Original Message-----
> From: Song Bao Hua (Barry Song)
> Sent: Wednesday, December 2, 2020 11:41 PM
> To: 'Vincent Guittot' <vincent.guittot at linaro.org>
> Cc: Valentin Schneider <valentin.schneider at arm.com>; Catalin Marinas
> <catalin.marinas at arm.com>; Will Deacon <will at kernel.org>; Rafael J. Wysocki
> <rjw at rjwysocki.net>; Cc: Len Brown <lenb at kernel.org>;
> gregkh at linuxfoundation.org; Jonathan Cameron <jonathan.cameron at huawei.com>;
> Ingo Molnar <mingo at redhat.com>; Peter Zijlstra <peterz at infradead.org>; Juri
> Lelli <juri.lelli at redhat.com>; Dietmar Eggemann <dietmar.eggemann at arm.com>;
> Steven Rostedt <rostedt at goodmis.org>; Ben Segall <bsegall at google.com>; Mel
> Gorman <mgorman at suse.de>; Mark Rutland <mark.rutland at arm.com>; LAK
> <linux-arm-kernel at lists.infradead.org>; linux-kernel
> <linux-kernel at vger.kernel.org>; ACPI Devel Maling List
> <linux-acpi at vger.kernel.org>; Linuxarm <linuxarm at huawei.com>; xuwei (O)
> <xuwei5 at huawei.com>; Zengtao (B) <prime.zeng at hisilicon.com>
> Subject: RE: [RFC PATCH v2 2/2] scheduler: add scheduler level for clusters
>
>
>
> > -----Original Message-----
> > From: Vincent Guittot [mailto:vincent.guittot at linaro.org]
> > Sent: Wednesday, December 2, 2020 11:17 PM
> > To: Song Bao Hua (Barry Song) <song.bao.hua at hisilicon.com>
> > Cc: Valentin Schneider <valentin.schneider at arm.com>; Catalin Marinas
> > <catalin.marinas at arm.com>; Will Deacon <will at kernel.org>; Rafael J. Wysocki
> > <rjw at rjwysocki.net>; Cc: Len Brown <lenb at kernel.org>;
> > gregkh at linuxfoundation.org; Jonathan Cameron <jonathan.cameron at huawei.com>;
> > Ingo Molnar <mingo at redhat.com>; Peter Zijlstra <peterz at infradead.org>; Juri
> > Lelli <juri.lelli at redhat.com>; Dietmar Eggemann <dietmar.eggemann at arm.com>;
> > Steven Rostedt <rostedt at goodmis.org>; Ben Segall <bsegall at google.com>; Mel
> > Gorman <mgorman at suse.de>; Mark Rutland <mark.rutland at arm.com>; LAK
> > <linux-arm-kernel at lists.infradead.org>; linux-kernel
> > <linux-kernel at vger.kernel.org>; ACPI Devel Maling List
> > <linux-acpi at vger.kernel.org>; Linuxarm <linuxarm at huawei.com>; xuwei (O)
> > <xuwei5 at huawei.com>; Zengtao (B) <prime.zeng at hisilicon.com>
> > Subject: Re: [RFC PATCH v2 2/2] scheduler: add scheduler level for clusters
> >
> > On Wed, 2 Dec 2020 at 10:20, Song Bao Hua (Barry Song)
> > <song.bao.hua at hisilicon.com> wrote:
> > >
> > >
> > >
> > > > -----Original Message-----
> > > > From: Vincent Guittot [mailto:vincent.guittot at linaro.org]
> > > > Sent: Wednesday, December 2, 2020 9:27 PM
> > > > To: Song Bao Hua (Barry Song) <song.bao.hua at hisilicon.com>
> > > > Cc: Valentin Schneider <valentin.schneider at arm.com>; Catalin Marinas
> > > > <catalin.marinas at arm.com>; Will Deacon <will at kernel.org>; Rafael J.
> Wysocki
> > > > <rjw at rjwysocki.net>; Cc: Len Brown <lenb at kernel.org>;
> > > > gregkh at linuxfoundation.org; Jonathan Cameron
> > <jonathan.cameron at huawei.com>;
> > > > Ingo Molnar <mingo at redhat.com>; Peter Zijlstra <peterz at infradead.org>;
> Juri
> > > > Lelli <juri.lelli at redhat.com>; Dietmar Eggemann
> > <dietmar.eggemann at arm.com>;
> > > > Steven Rostedt <rostedt at goodmis.org>; Ben Segall <bsegall at google.com>;
> Mel
> > > > Gorman <mgorman at suse.de>; Mark Rutland <mark.rutland at arm.com>; LAK
> > > > <linux-arm-kernel at lists.infradead.org>; linux-kernel
> > > > <linux-kernel at vger.kernel.org>; ACPI Devel Maling List
> > > > <linux-acpi at vger.kernel.org>; Linuxarm <linuxarm at huawei.com>; xuwei (O)
> > > > <xuwei5 at huawei.com>; Zengtao (B) <prime.zeng at hisilicon.com>
> > > > Subject: Re: [RFC PATCH v2 2/2] scheduler: add scheduler level for clusters
> > > >
> > > > On Tue, 1 Dec 2020 at 04:04, Barry Song <song.bao.hua at hisilicon.com> wrote:
> > > > >
> > > > > ARM64 server chip Kunpeng 920 has 6 clusters in each NUMA node, and
> each
> > > > > cluster has 4 cpus. All clusters share L3 cache data, but each cluster
> > > > > has local L3 tag. On the other hand, each clusters will share some
> > > > > internal system bus. This means cache coherence overhead inside one
> cluster
> > > > > is much less than the overhead across clusters.
> > > > >
> > > > > +-----------------------------------+ +---------+
> > > > > | +------+ +------+ +---------------------------+ |
> > > > > | | CPU0 | | cpu1 | | +-----------+ | |
> > > > > | +------+ +------+ | | | | |
> > > > > | +----+ L3 | | |
> > > > > | +------+ +------+ cluster | | tag | | |
> > > > > | | CPU2 | | CPU3 | | | | | |
> > > > > | +------+ +------+ | +-----------+ | |
> > > > > | | | |
> > > > > +-----------------------------------+ | |
> > > > > +-----------------------------------+ | |
> > > > > | +------+ +------+ +--------------------------+ |
> > > > > | | | | | | +-----------+ | |
> > > > > | +------+ +------+ | | | | |
> > > > > | | | L3 | | |
> > > > > | +------+ +------+ +----+ tag | | |
> > > > > | | | | | | | | | |
> > > > > | +------+ +------+ | +-----------+ | |
> > > > > | | | |
> > > > > +-----------------------------------+ | L3 |
> > > > > | data |
> > > > > +-----------------------------------+ | |
> > > > > | +------+ +------+ | +-----------+ | |
> > > > > | | | | | | | | | |
> > > > > | +------+ +------+ +----+ L3 | | |
> > > > > | | | tag | | |
> > > > > | +------+ +------+ | | | | |
> > > > > | | | | | ++ +-----------+ | |
> > > > > | +------+ +------+ |---------------------------+ |
> > > > > +-----------------------------------| | |
> > > > > +-----------------------------------| | |
> > > > > | +------+ +------+ +---------------------------+ |
> > > > > | | | | | | +-----------+ | |
> > > > > | +------+ +------+ | | | | |
> > > > > | +----+ L3 | | |
> > > > > | +------+ +------+ | | tag | | |
> > > > > | | | | | | | | | |
> > > > > | +------+ +------+ | +-----------+ | |
> > > > > | | | |
> > > > > +-----------------------------------+ | |
> > > > > +-----------------------------------+ | |
> > > > > | +------+ +------+ +--------------------------+ |
> > > > > | | | | | | +-----------+ | |
> > > > > | +------+ +------+ | | | | |
> > > > > | | | L3 | | |
> > > > > | +------+ +------+ +---+ tag | | |
> > > > > | | | | | | | | | |
> > > > > | +------+ +------+ | +-----------+ | |
> > > > > | | | |
> > > > > +-----------------------------------+ | |
> > > > > +-----------------------------------+ ++ |
> > > > > | +------+ +------+ +--------------------------+ |
> > > > > | | | | | | +-----------+ | |
> > > > > | +------+ +------+ | | | | |
> > > > > | | | L3 | | |
> > > > > | +------+ +------+ +--+ tag | | |
> > > > > | | | | | | | | | |
> > > > > | +------+ +------+ | +-----------+ | |
> > > > > | | +---------+
> > > > > +-----------------------------------+
> > > > >
> > > > > This patch adds the sched_domain for clusters. On kunpeng 920, without
> > > > > this patch, domain0 of cpu0 would be MC for cpu0-cpu23 with
> > > > > min_interval=24, max_interval=48; with this patch, MC becomes domain1,
> > > > > a new domain0 "CL" including cpu0-cpu3 is added with min_interval=4
> and
> > > > > max_interval=8.
> > > > > This will affect load balance. For example, without this patch, while
> > cpu0
> > > > > becomes idle, it will pull a task from cpu1-cpu15. With this patch,
> cpu0
> > > > > will try to pull a task from cpu1-cpu3 first. This will have much less
> > > > > overhead of task migration.
> > > > >
> > > > > On the other hand, while doing WAKE_AFFINE, this patch will try to find
> > > > > a core in the target cluster before scanning the llc domain.
> > > > > This means it will proactively use a core which has better affinity
> with
> > > > > target core at first.
> > > >
> > > > Which is at the opposite of what we are usually trying to do in the
> > > > fast wakeup path: trying to minimize resource sharing by finding an
> > > > idle core with all smt idle as an example
> > >
> > > In wake_affine case, I guess we are actually want some kind of
> > > resource sharing such as LLC to get waker and wakee get closer
> >
> > In wake_affine, we don't want to move outside the LLC but then in the
> > LLC we tries to minimize resource sharing like looking for a core
> > fully idle for SMT
> >
> > > to each other. find_idlest_cpu() is really opposite.
> > >
> > > So the real question is that LLC is always the right choice of
> > > idle sibling?
> >
> > That's the eternal question: spread or gather
>
> Indeed.
>
> >
> > >
> > > In this case, 6 clusters are in same LLC, but hardware has different
> > > behavior for inside single cluster and across multiple clusters.
> > >
> > >
> > > >
> > > > >
> > > > > Not much benchmark has been done yet. but here is a rough hackbench
> > > > > result.
> > > > > we run the below command with different -g parameter to increase system
> > load
> > > > > by changing g from 1 to 4, for each one of 1-4, we run the benchmark
> ten
> > times
> > > > > and record the data to get the average time:
> > > > >
> > > > > First, we run hackbench in only one NUMA node(cpu0-cpu23):
> > > > > $ numactl -N 0 hackbench -p -T -l 100000 -g $1
> > > >
> > > > What is your ref tree ? v5.10-rcX or tip/sched/core ?
> > >
> > > Actually I was using 5.9 release. That must be weird.
> > > But the reason is that disk driver is getting hang
> > > in my hardware in 5.10-rcx.
> >
> > In fact there are several changes in v5.10 and tip/sched/core that
> > could help your topology
>
> Will figure out some way to try.
>
> >
> > >
> > > >
> > > > >
> > > > > g=1 (seen cpu utilization around 50% for each core)
> > > > > Running in threaded mode with 1 groups using 40 file descriptors
> > > > > Each sender will pass 100000 messages of 100 bytes
> > > > > w/o: 7.689 7.485 7.485 7.458 7.524 7.539 7.738 7.693 7.568 7.674=7.5853
> > > > > w/ : 7.516 7.941 7.374 7.963 7.881 7.910 7.420 7.556 7.695 7.441=7.6697
> > > > > performance improvement w/ patch: -1.01%
> > > > >
> > > > > g=2 (seen cpu utilization around 70% for each core)
> > > > > Running in threaded mode with 2 groups using 40 file descriptors
> > > > > Each sender will pass 100000 messages of 100 bytes
> > > > > w/o: 10.127 10.119 10.070 10.196 10.057 10.111 10.045 10.164 10.162
> > > > 9.955=10.1006
> > > > > w/ : 9.694 9.654 9.612 9.649 9.686 9.734 9.607 9.842 9.690 9.710=9.6878
> > > > > performance improvement w/ patch: 4.08%
> > > > >
> > > > > g=3 (seen cpu utilization around 90% for each core)
> > > > > Running in threaded mode with 3 groups using 40 file descriptors
> > > > > Each sender will pass 100000 messages of 100 bytes
> > > > > w/o: 15.885 15.254 15.932 15.647 16.120 15.878 15.857 15.759 15.674
> > > > 15.721=15.7727
> > > > > w/ : 14.974 14.657 13.969 14.985 14.728 15.665 15.191 14.995 14.946
> > > > 14.895=14.9005
> > > > > performance improvement w/ patch: 5.53%
> > > > >
> > > > > g=4
> > > > > Running in threaded mode with 4 groups using 40 file descriptors
> > > > > Each sender will pass 100000 messages of 100 bytes
> > > > > w/o: 20.014 21.025 21.119 21.235 19.767 20.971 20.962 20.914 21.090
> > > > 21.090=20.8187
> > > > > w/ : 20.331 20.608 20.338 20.445 20.456 20.146 20.693 20.797 21.381
> > > > 20.452=20.5647
> > > > > performance improvement w/ patch: 1.22%
> > > > >
> > > > > After that, we run the same hackbench in both NUMA nodes(cpu0-cpu47):
> > > > > g=1
> > > > > w/o: 7.351 7.416 7.486 7.358 7.516 7.403 7.413 7.411 7.421 7.454=7.4229
> > > > > w/ : 7.609 7.596 7.647 7.571 7.687 7.571 7.520 7.513 7.530 7.681=7.5925
> > > > > performance improvement by patch: -2.2%
> > > > >
> > > > > g=2
> > > > > w/o: 9.046 9.190 9.053 8.950 9.101 8.930 9.143 8.928 8.905 9.034=9.028
> > > > > w/ : 8.247 8.057 8.258 8.310 8.083 8.201 8.044 8.158 8.382 8.173=8.1913
> > > > > performance improvement by patch: 9.3%
> > > > >
> > > > > g=3
> > > > > w/o: 11.664 11.767 11.277 11.619 12.557 12.760 11.664 12.165 12.235
> > > > 11.849=11.9557
> > > > > w/ : 9.387 9.461 9.650 9.613 9.591 9.454 9.496 9.716 9.327 9.722=9.5417
> > > > > performance improvement by patch: 20.2%
> > > > >
> > > > > g=4
> > > > > w/o: 17.347 17.299 17.655 18.775 16.707 18.879 17.255 18.356 16.859
> > > > 18.515=17.7647
> > > > > w/ : 10.416 10.496 10.601 10.318 10.459 10.617 10.510 10.642 10.467
> > > > 10.401=10.4927
> > > > > performance improvement by patch: 40.9%
> > > > >
> > > > > g=5
> > > > > w/o: 27.805 26.633 24.138 28.086 24.405 27.922 30.043 28.458 31.073
> > > > 25.819=27.4382
> > > > > w/ : 13.817 13.976 14.166 13.688 14.132 14.095 14.003 13.997 13.954
> > > > 13.907=13.9735
> > > > > performance improvement by patch: 49.1%
> > > > >
> > > > > It seems the patch can bring a huge increase on hackbench especially
> when
> > > > > we bind hackbench to all of cpu0-cpu47, comparing to 5.53% while running
> > > > > on single NUMA node(cpu0-cpu23)
> > > >
> > > > Interesting that this patch mainly impacts the numa case
> > > >
> > > > >
> > > > > Signed-off-by: Barry Song <song.bao.hua at hisilicon.com>
> > > > > ---
> > > > > arch/arm64/Kconfig | 7 +++++++
> > > > > arch/arm64/kernel/smp.c | 17 +++++++++++++++++
> > > > > include/linux/topology.h | 7 +++++++
> > > > > kernel/sched/fair.c | 35 +++++++++++++++++++++++++++++++++++
> > > > > 4 files changed, 66 insertions(+)
> > > > >
> > > > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> > > > > index 6d23283..3583c26 100644
> > > > > --- a/arch/arm64/Kconfig
> > > > > +++ b/arch/arm64/Kconfig
> > > > > @@ -938,6 +938,13 @@ config SCHED_MC
> > > > > making when dealing with multi-core CPU chips at a cost of slightly
> > > > > increased overhead in some places. If unsure say N here.
> > > > >
> > > > > +config SCHED_CLUSTER
> > > > > + bool "Cluster scheduler support"
> > > > > + help
> > > > > + Cluster scheduler support improves the CPU scheduler's decision
> > > > > + making when dealing with machines that have clusters(sharing
> > internal
> > > > > + bus or sharing LLC cache tag). If unsure say N here.
> > > > > +
> > > > > config SCHED_SMT
> > > > > bool "SMT scheduler support"
> > > > > help
> > > > > diff --git a/arch/arm64/kernel/smp.c b/arch/arm64/kernel/smp.c
> > > > > index 355ee9e..5c8f026 100644
> > > > > --- a/arch/arm64/kernel/smp.c
> > > > > +++ b/arch/arm64/kernel/smp.c
> > > > > @@ -32,6 +32,7 @@
> > > > > #include <linux/irq_work.h>
> > > > > #include <linux/kexec.h>
> > > > > #include <linux/kvm_host.h>
> > > > > +#include <linux/sched/topology.h>
> > > > >
> > > > > #include <asm/alternative.h>
> > > > > #include <asm/atomic.h>
> > > > > @@ -726,6 +727,20 @@ void __init smp_init_cpus(void)
> > > > > }
> > > > > }
> > > > >
> > > > > +static struct sched_domain_topology_level arm64_topology[] = {
> > > > > +#ifdef CONFIG_SCHED_SMT
> > > > > + { cpu_smt_mask, cpu_smt_flags, SD_INIT_NAME(SMT) },
> > > > > +#endif
> > > > > +#ifdef CONFIG_SCHED_CLUSTER
> > > > > + { cpu_clustergroup_mask, cpu_core_flags, SD_INIT_NAME(CL) },
> > > > > +#endif
> > > > > +#ifdef CONFIG_SCHED_MC
> > > > > + { cpu_coregroup_mask, cpu_core_flags, SD_INIT_NAME(MC) },
> > > > > +#endif
> > > > > + { cpu_cpu_mask, SD_INIT_NAME(DIE) },
> > > > > + { NULL, },
> > > > > +};
> > > > > +
> > > > > void __init smp_prepare_cpus(unsigned int max_cpus)
> > > > > {
> > > > > const struct cpu_operations *ops;
> > > > > @@ -735,6 +750,8 @@ void __init smp_prepare_cpus(unsigned int max_cpus)
> > > > >
> > > > > init_cpu_topology();
> > > > >
> > > > > + set_sched_topology(arm64_topology);
> > > > > +
> > > > > this_cpu = smp_processor_id();
> > > > > store_cpu_topology(this_cpu);
> > > > > numa_store_cpu_info(this_cpu);
> > > > > diff --git a/include/linux/topology.h b/include/linux/topology.h
> > > > > index 5f66648..2c823c0 100644
> > > > > --- a/include/linux/topology.h
> > > > > +++ b/include/linux/topology.h
> > > > > @@ -211,6 +211,13 @@ static inline const struct cpumask *cpu_smt_mask(int
> > > > cpu)
> > > > > }
> > > > > #endif
> > > > >
> > > > > +#ifdef CONFIG_SCHED_CLUSTER
> > > > > +static inline const struct cpumask *cpu_cluster_mask(int cpu)
> > > > > +{
> > > > > + return topology_cluster_cpumask(cpu);
> > > > > +}
> > > > > +#endif
> > > > > +
> > > > > static inline const struct cpumask *cpu_cpu_mask(int cpu)
> > > > > {
> > > > > return cpumask_of_node(cpu_to_node(cpu));
> > > > > diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
> > > > > index 1a68a05..ae8ec910 100644
> > > > > --- a/kernel/sched/fair.c
> > > > > +++ b/kernel/sched/fair.c
> > > > > @@ -6106,6 +6106,37 @@ static inline int select_idle_smt(struct
> task_struct
> > > > *p, int target)
> > > > >
> > > > > #endif /* CONFIG_SCHED_SMT */
> > > > >
> > > > > +#ifdef CONFIG_SCHED_CLUSTER
> > > > > +/*
> > > > > + * Scan the local CLUSTER mask for idle CPUs.
> > > > > + */
> > > > > +static int select_idle_cluster(struct task_struct *p, int target)
> > > > > +{
> > > > > + int cpu;
> > > > > +
> > > > > + /* right now, no hardware with both cluster and smt to run */
> > > > > + if (sched_smt_active())
> > > >
> > > > don't use smt static key but a dedicated one if needed
> > >
> > > Sure.
> > >
> > > >
> > > > > + return -1;
> > > > > +
> > > > > + for_each_cpu_wrap(cpu, cpu_cluster_mask(target), target) {
> > > > > + if (!cpumask_test_cpu(cpu, p->cpus_ptr))
> > > > > + continue;
> > > > > + if (available_idle_cpu(cpu))
> > > > > + return cpu;
> > > > > + }
> > > > > +
> > > > > + return -1;
> > > > > +}
> > > > > +
> > > > > +#else /* CONFIG_SCHED_CLUSTER */
> > > > > +
> > > > > +static inline int select_idle_cluster(struct task_struct *p, int target)
> > > > > +{
> > > > > + return -1;
> > > > > +}
> > > > > +
> > > > > +#endif /* CONFIG_SCHED_CLUSTER */
> > > > > +
> > > > > /*
> > > > > * Scan the LLC domain for idle CPUs; this is dynamically regulated
> by
> > > > > * comparing the average scan cost (tracked in sd->avg_scan_cost) against
> > > > the
> > > > > @@ -6270,6 +6301,10 @@ static int select_idle_sibling(struct task_struct
> > *p,
> > > > int prev, int target)
> > > > > if ((unsigned)i < nr_cpumask_bits)
> > > > > return i;
> > > > >
> > > > > + i = select_idle_cluster(p, target);
> > > > > + if ((unsigned)i < nr_cpumask_bits)
> > > > > + return i;
> > > >
> > > > This is yet another loop in the fast wake up path.
> > > >
> > > > I'm curious to know which part of this patch really gives the perf
> improvement ?
> > > > -Is it the new sched domain level with a shorter interval that is then
> > > > used by Load balance to better spread task in the cluster and between
> > > > clusters ?
> > > > -Or this new loop in the wake up path which tries to keep threads in
> > > > the same cluster ? which is at the opposite of the rest of the
> > > > scheduler which tries to spread
> > >
> > > If I don't scan cluster first for wake_affine, I almost don't see large
> > > hackbench change by the new sche_domain.
> > > For example:
> > > g=4 in hackbench on cpu0-cpu47(two numa)
> > > w/o patch: 17.7647 (average time in 10 times of hackbench)
> > > w/ the full patch: 10.4927
> > > w/ patch but drop select_idle_cluster(): 15.0931
> >
> > And for the case with one numa node ?
>
> That would be very frustrating as it is getting worse:
>
> g=1
> Running in threaded mode with 1 groups using 40 file descriptors
> Each sender will pass 100000 messages of 100 bytes
> w/o: 7.689 7.485 7.485 7.458 7.524 7.539 7.738 7.693 7.568 7.674=7.5853
> w/ : 7.516 7.941 7.374 7.963 7.881 7.910 7.420 7.556 7.695 7.441=7.6697
> w/ but dropped select_idle_cluster:
> 7.816 7.589 7.319 7.556 7.443 7.459 7.636 7.427 7.425 7.395=7.5065
>
> g=2
> Running in threaded mode with 2 groups using 40 file descriptors
> Each sender will pass 100000 messages of 100 bytes
> w/o: 10.127 10.119 10.070 10.196 10.057 10.111 10.045 10.164 10.162
> 9.955=10.1006
> w/ : 9.694 9.654 9.612 9.649 9.686 9.734 9.607 9.842 9.690 9.710=9.6878
> w/ but dropped select_idle_cluster:
> 10.222 10.078 10.063 10.317 9.963 10.060 10.089 9.934 10.152 10.077=10.0955
>
> g=3
> Running in threaded mode with 3 groups using 40 file descriptors
> Each sender will pass 100000 messages of 100 bytes
> w/o: 15.885 15.254 15.932 15.647 16.120 15.878 15.857 15.759 15.674
> 15.721=15.7727
> w/ : 14.974 14.657 13.969 14.985 14.728 15.665 15.191 14.995 14.946
> 14.895=14.9005
> w/ but dropped select_idle_cluster(getting worse than w/o):
> 16.892 16.962 17.248 17.392 17.336 17.705 17.113 17.633 17.477
> 17.378=17.3136
>
> g=4
> Running in threaded mode with 4 groups using 40 file descriptors
> Each sender will pass 100000 messages of 100 bytes
> w/o: 20.014 21.025 21.119 21.235 19.767 20.971 20.962 20.914 21.090
> 21.090=20.8187
> w/ : 20.331 20.608 20.338 20.445 20.456 20.146 20.693 20.797 21.381
> 20.452=20.5647
> w/ but dropped select_idle_cluster(getting worse than w/o):
> 24.075 24.122 24.243 24.000 24.223 23.791 23.246 24.904 23.990
> 24.431=24.1025
Sorry. Please ignore this. I added some printk here while testing
one numa. Will update you the data in another email.
Thanks
Barry
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