[dpdk-dev] [PATCH 0/3] eal affinitize low priority threads to lcore 0
Stephen Hemminger
stephen at networkplumber.org
Fri Sep 12 03:24:24 CEST 2014
On Thu, 11 Sep 2014 23:47:52 +0000
Hiroshi Shimamoto <h-shimamoto at ct.jp.nec.com> wrote:
> Hi Bruce,
>
> > Subject: [dpdk-dev] [PATCH 0/3] eal affinitize low priority threads to lcore 0
> >
> > This patchset sets things up so that we can affinitize the interrupt,
> > vfio management, and hpet timer management threads to lcore 0, so that
> > they never interfere with data plane threads.
>
> I don't think it works well always.
> The management threads can be floating all cpus on demand, because those
> threads are created before the master thread affinity is set. The kernel
> scheduler will take care of it. And we should isolate cpus which data plane
> threads are pinned to, so the management threads cannot run on those isolated
> cpus data plane thread run.
> In some cases, the user may run data plane thread on lcore 0, but with
> this patchset the data plane pinned to lcore 0 always run with the
> management threads. That doesn't seem good.
>
> I think this functionality should be conditional.
> How about to add a parameter to specify the mask for the management threads
> instead of statically assignment to lcore 0?
>
> thanks,
> Hiroshi
>
> >
> > Bruce Richardson (3):
> > eal: add core id param to eal_thread_set_affinity
> > eal: increase scope of eal_thread_set_affinity
> > eal: affinitize low-priority threads to lcore 0
> >
> > lib/librte_eal/bsdapp/eal/eal_thread.c | 12 ++++++------
> > lib/librte_eal/common/include/eal_private.h | 10 ++++++++++
> > lib/librte_eal/linuxapp/eal/eal_interrupts.c | 5 +++++
> > lib/librte_eal/linuxapp/eal/eal_pci_vfio_mp_sync.c | 6 ++++++
> > lib/librte_eal/linuxapp/eal/eal_thread.c | 12 ++++++------
> > lib/librte_eal/linuxapp/eal/eal_timer.c | 5 +++++
> > 6 files changed, 38 insertions(+), 12 deletions(-)
> >
> > --
> > 1.9.3
>
We just set the non-master DPDK worker threads to be real time by
using pthread_set_scheduler. This works very well and makes it clear to
Linux scheduler what the intention is. This also improves wakeup behavior
from sleeps.
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