[dpdk-dev] [PATCH 0/8] Remove IPC threads

Zhang, Qi Z qi.z.zhang at intel.com
Tue Jun 26 09:03:01 CEST 2018


> -----Original Message-----
> From: Zhang, Qi Z
> Sent: Tuesday, June 26, 2018 9:19 AM
> To: 'Anatoly Burakov' <anatoly.burakov at intel.com>; dev at dpdk.org
> Cc: Ananyev, Konstantin <konstantin.ananyev at intel.com>;
> thomas at monjalon.net; Richardson, Bruce <bruce.richardson at intel.com>
> Subject: RE: [dpdk-dev] [PATCH 0/8] Remove IPC threads
> 
> Hi Anatoly and Thomas:
> 
> Sorry for raise this late, but seems merge mp thread into interrupt thread gives
> problem to enable hotplug on secondary [1].
> 
> The issue is, when secondary want to attach a share device, it send request to
> primary Then primary is running in mp callback (mp thread) to attach device, it
> will call rte_malloc which get chance to increase heap that will do sync IPC, You
> know, this is the limitation we can't do sync IPC in mp thread itself. so the
> solution is try to move real work to a separate thread which has no limitation
> to do sync IPC, and interrupt thread is the good candidate, because we just
> need to call rte_eal_set_alarm and we don't need to worry about the
> execution sequence.
> 
> But if we merge mp thread into interrupt thread, the solution will not work, we
> may need to create specific temporal thread to handle callback, but this looks
> like some re-build which we already have.

Ok, actually this method looks good to me :), I will send v4 to have this,
But please let me know if you have better idea.

> So I think we need to revisit if we need to merge the thread before we have a
> good solution for such kind of issue.
> 
> Thanks
> Qi
> 
> [1] https://mails.dpdk.org/archives/dev/2018-June/105018.html
> 
> 
> > -----Original Message-----
> > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Anatoly Burakov
> > Sent: Friday, June 15, 2018 10:25 PM
> > To: dev at dpdk.org
> > Cc: Ananyev, Konstantin <konstantin.ananyev at intel.com>;
> > thomas at monjalon.net; Richardson, Bruce <bruce.richardson at intel.com>
> > Subject: [dpdk-dev] [PATCH 0/8] Remove IPC threads
> >
> > As previously discussed [1], IPC threads need to be removed and their
> > workload moved to interrupt thread.
> >
> > FreeBSD did not have an interrupt thread, nor did it support alarm
> > API. This patchset adds support for both on FreeBSD. FreeBSD interrupt
> > thread is based on kevent, FreeBSD's native event multiplexing
> > mechanism similar to Linux's epoll.
> >
> > The patchset makes FreeBSD's interrupts and alarm work just enough to
> > suffice for purposes of IPC, however there are really weird problems
> observed.
> > Specifically, FreeBSD's kevent timers are really slow to trigger for
> > some reason, sleeping on a 10ms timer as much as 200ms before waking
> > up. Interrupt handling on fd's is also a bit flaky.
> >
> > It has also been observed that both problems go away if we do not
> > affinitize master lcore (by commenting relevant code out [2]). It is
> > not known why these problems are observed, nor it is clear what a solution
> might entail.
> >
> > For the purposes of making IPC work and having rudimentary support for
> > alarm and interrupt API's, this patchset works fine. However, because
> > of the above described issues, documentation will not be updated to
> > indicate support for interrupts on FreeBSD at this time.
> >
> > [1] http://dpdk.org/dev/patchwork/patch/36579/
> > [2]
> > http://dpdk.org/browse/dpdk/tree/lib/librte_eal/bsdapp/eal/eal.c#n729
> >
> > Anatoly Burakov (4):
> >   ipc: remove IPC thread for async requests
> >   eal/bsdapp: add interrupt thread
> >   eal/bsdapp: add alarm support
> >   ipc: remove main IPC thread
> >
> > Jianfeng Tan (4):
> >   eal/linux: use glibc malloc in alarm
> >   eal/linux: use glibc malloc in interrupt handling
> >   eal: bring forward init of interrupt handling
> >   eal: add IPC type for interrupt thread
> >
> >  lib/librte_eal/bsdapp/eal/eal.c               |  10 +-
> >  lib/librte_eal/bsdapp/eal/eal_alarm.c         | 299 +++++++++++-
> >  lib/librte_eal/bsdapp/eal/eal_alarm_private.h |  19 +
> >  lib/librte_eal/bsdapp/eal/eal_interrupts.c    | 460 +++++++++++++++++-
> >  lib/librte_eal/common/eal_common_proc.c       | 243 ++++-----
> >  .../common/include/rte_eal_interrupts.h       |   1 +
> >  lib/librte_eal/linuxapp/eal/eal.c             |  10 +-
> >  lib/librte_eal/linuxapp/eal/eal_alarm.c       |   9 +-
> >  lib/librte_eal/linuxapp/eal/eal_interrupts.c  |  19 +-
> >  test/test/test_interrupts.c                   |  29 +-
> >  10 files changed, 899 insertions(+), 200 deletions(-)  create mode
> > 100644 lib/librte_eal/bsdapp/eal/eal_alarm_private.h
> >
> > --
> > 2.17.1


More information about the dev mailing list