Hi,
> -----Original Message-----
> From: Olivier MATZ [mailto:olivier.matz at 6wind.com]
> Sent: Thursday, February 12, 2015 7:16 PM
> To: Liang, Cunming; dev at dpdk.org
> Cc: Ananyev, Konstantin
> Subject: Re: [PATCH v5 18/19] ring: add sched_yield to avoid spin forever
>
> Hi,
>
> On 02/12/2015 09:16 AM, Cunming Liang wrote:
> > Add a sched_yield() syscall if the thread spins for too long, waiting other
> > thread
> to finish its operations on the ring.
> > That gives pre-empted thread a chance to proceed and finish with ring
> enqnue/dequeue operation.
> > The purpose is to reduce contention on the ring. By ring_perf_test, it
> > doesn't
> shows additional perf penalty.
> >
> > Signed-off-by: Cunming Liang <cunming.liang at intel.com>
> > ---
> > v5 changes:
> > add RTE_RING_PAUSE_REP to config file
> >
> > v4 changes:
> > update and add more comments on sched_yield()
> >
> > v3 changes:
> > new patch adding sched_yield() in rte_ring to avoid long spin
> >
> > config/common_bsdapp | 1 +
> > config/common_linuxapp | 1 +
> > lib/librte_ring/rte_ring.h | 31 +++++++++++++++++++++++++++----
> > 3 files changed, 29 insertions(+), 4 deletions(-)
> >
> > diff --git a/config/common_bsdapp b/config/common_bsdapp
> > index 57bacb8..52c5143 100644
> > --- a/config/common_bsdapp
> > +++ b/config/common_bsdapp
> > @@ -234,6 +234,7 @@ CONFIG_RTE_PMD_PACKET_PREFETCH=y
> > CONFIG_RTE_LIBRTE_RING=y
> > CONFIG_RTE_LIBRTE_RING_DEBUG=n
> > CONFIG_RTE_RING_SPLIT_PROD_CONS=n
> > +CONFIG_RTE_RING_PAUSE_REP=n
>
> Maybe it's better to use CONFIG_RTE_RING_PAUSE_REP=0 instead?
> If I understand well, it has to be set to an integer value to
> enable it, am I correct?
[LCM] If RTE_RING_PAUSE_REP=N (no define), by default will use 0. If it's set
to 'y'(=1), will issue yield in the most frequent rate.
It also can set as integer to assign any number. All cases works for this
configure.
One point is in configure file, just demonstrate the default way to use it.
It can't prevent to use anything unexpected. Except we rule the n & y illegal
for this option.
The meaningful value of it can write in the doc.
>
> Thanks,
> Olivier
