From: Bruce Richardson <bruce.richardson@intel.com>
To: Neil Horman <nhorman@tuxdriver.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH RFC 0/3] DPDK ethdev callback support
Date: Tue, 23 Dec 2014 09:28:08 +0000 [thread overview]
Message-ID: <20141223092808.GB10244@bricha3-MOBL3> (raw)
In-Reply-To: <20141222174709.GE26669@hmsreliant.think-freely.org>
On Mon, Dec 22, 2014 at 12:47:09PM -0500, Neil Horman wrote:
> On Mon, Dec 22, 2014 at 05:33:07PM +0000, Bruce Richardson wrote:
> > On Mon, Dec 22, 2014 at 06:02:53PM +0100, Thomas Monjalon wrote:
> > > Hi Bruce,
> > >
> > > Callbacks, as hooks for applications, give more flexibility and are
> > > generally a good idea.
> > > In DPDK the main issue will be to avoid performance degradation.
> > > I see you use "unlikely" for callback branching.
> > > Could we reduce more the impact of this test by removing the queue array,
> > > i.e. having port-wide callbacks instead of per-queue callbacks?
> >
> > I can give that a try, but I don't see it making much difference if any. The
> > main thing to avoid with branching is branch mis-prediction, which should not
> > be a problem here, as the user is not going to be adding or removing callbacks
> > between each RX and TX call, making the branches highly predictable - i.e. always
> > go the same way.
> I was going to ask about exactly that. You say no one will be adding/removing
> callbacks between RX/TX calls, but you don't know that, people will try to do so
> at some point. You should add a check so that callbacks can only be
> registered/unregistered on stopped queues, otherwise this is extreemely racy.
> it won't impact performance to do so, and will save a good deal of debugging
> down the road at some point.
>
> Neil
>
Actually, I think it's worthwhile being able to do exactly that - add/remove
callbacks on the fly, if possible. Doing the add in a race-free manner is probably
easy enough, but doing the delete may well be more tricky. For now, though,
it might indeed be as well to limit it to stopped queues.
If we can do the dynamic add/remove of callbacks, then that can lead to all
sorts of interesting runtime instrumentation possibilities using multiprocess
support.
/Bruce
next prev parent reply other threads:[~2014-12-23 9:28 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-22 16:47 Bruce Richardson
2014-12-22 16:47 ` [dpdk-dev] [PATCH RFC 1/3] ethdev: rename callbacks field to intr_cbs Bruce Richardson
2014-12-22 16:47 ` [dpdk-dev] [PATCH RFC 2/3] ethdev: Add in data rxtx callback support Bruce Richardson
2014-12-22 16:47 ` [dpdk-dev] [PATCH RFC 3/3] examples: example showing use of callbacks Bruce Richardson
2014-12-22 17:02 ` [dpdk-dev] [PATCH RFC 0/3] DPDK ethdev callback support Thomas Monjalon
2014-12-22 17:33 ` Bruce Richardson
2014-12-22 17:47 ` Neil Horman
2014-12-23 9:28 ` Bruce Richardson [this message]
2014-12-23 13:09 ` Neil Horman
2014-12-23 14:09 ` Bruce Richardson
2015-01-05 16:17 ` Bruce Richardson
2014-12-22 18:31 ` Stephen Hemminger
2014-12-23 9:29 ` Bruce Richardson
2014-12-23 4:23 ` Vithal S Mohare
2014-12-23 9:30 ` Bruce Richardson
2014-12-23 9:37 ` Vithal S Mohare
2014-12-24 1:43 ` Zhang, Helin
2014-12-24 5:06 ` Qiu, Michael
2015-02-12 19:57 ` [dpdk-dev] [PATCH " John McNamara
2015-02-12 19:57 ` [dpdk-dev] [PATCH 1/3] ethdev: rename callbacks field to intr_cbs John McNamara
2015-02-12 19:57 ` [dpdk-dev] [PATCH 2/3] ethdev: Add in data rxtx callback support John McNamara
2015-02-12 21:12 ` Neil Horman
2015-02-12 19:57 ` [dpdk-dev] [PATCH 3/3] examples: example showing use of callbacks John McNamara
2015-02-13 14:54 ` [dpdk-dev] [PATCH 0/3] DPDK ethdev callback support Declan Doherty
2015-02-13 15:39 ` [dpdk-dev] [PATCH v2 0/4] " John McNamara
2015-02-13 15:39 ` [dpdk-dev] [PATCH v2 1/4] ethdev: rename callbacks field to intr_cbs John McNamara
2015-02-13 16:06 ` Thomas Monjalon
2015-02-13 16:52 ` Thomas Monjalon
2015-02-13 15:39 ` [dpdk-dev] [PATCH v2 2/4] ethdev: Add in data rxtx callback support John McNamara
2015-02-13 16:33 ` Thomas Monjalon
2015-02-13 17:49 ` Bruce Richardson
2015-02-13 15:39 ` [dpdk-dev] [PATCH v2 3/4] examples: example showing use of callbacks John McNamara
2015-02-13 16:02 ` Thomas Monjalon
2015-02-16 14:33 ` Olivier MATZ
2015-02-16 15:16 ` Bruce Richardson
2015-02-16 17:34 ` Thomas Monjalon
2015-02-17 12:17 ` Declan Doherty
2015-02-17 12:25 ` Bruce Richardson
2015-02-17 13:28 ` Olivier MATZ
2015-02-17 13:50 ` Bruce Richardson
2015-02-17 15:49 ` Neil Horman
2015-02-17 16:00 ` Bruce Richardson
2015-02-17 16:08 ` Neil Horman
2015-02-17 16:15 ` Bruce Richardson
2015-02-17 19:27 ` Neil Horman
2015-02-17 15:32 ` Thomas Monjalon
2015-02-17 15:58 ` Bruce Richardson
2015-02-13 15:39 ` [dpdk-dev] [PATCH v2 4/4] abi: Added rxtx callback functions to ABI versioning John McNamara
2015-02-13 15:59 ` Thomas Monjalon
2015-02-13 15:48 ` [dpdk-dev] [PATCH v2 0/4] DPDK ethdev callback support Declan Doherty
2015-02-18 17:42 ` [dpdk-dev] [PATCH v3 0/3] " John McNamara
2015-02-18 17:42 ` [dpdk-dev] [PATCH v3 1/3] ethdev: Rename callbacks field to link_intr_cbs John McNamara
2015-02-18 17:42 ` [dpdk-dev] [PATCH v3 2/3] ethdev: Add rxtx callback support John McNamara
2015-02-18 18:19 ` Thomas Monjalon
2015-02-19 9:33 ` Mcnamara, John
2015-02-18 17:42 ` [dpdk-dev] [PATCH v3 3/3] examples: example showing use of callbacks John McNamara
2015-02-19 17:56 ` [dpdk-dev] [PATCH v4 0/3] DPDK ethdev callback support John McNamara
2015-02-19 17:56 ` [dpdk-dev] [PATCH v4 1/3] ethdev: rename callbacks field to link_intr_cbs John McNamara
2015-02-19 17:56 ` [dpdk-dev] [PATCH v4 2/3] ethdev: add optional rxtx callback support John McNamara
2015-02-20 10:06 ` Bruce Richardson
2015-02-20 10:31 ` Thomas Monjalon
2015-02-19 17:56 ` [dpdk-dev] [PATCH v4 3/3] examples: example showing use of callbacks John McNamara
2015-02-20 17:03 ` [dpdk-dev] [PATCH v5 0/3] DPDK ethdev callback support John McNamara
2015-02-20 17:03 ` [dpdk-dev] [PATCH v5 1/3] ethdev: rename callbacks field to link_intr_cbs John McNamara
2015-02-20 17:03 ` [dpdk-dev] [PATCH v5 2/3] ethdev: add optional rxtx callback support John McNamara
2015-02-23 15:11 ` Thomas Monjalon
2015-02-23 17:27 ` Mcnamara, John
2015-02-20 17:03 ` [dpdk-dev] [PATCH v5 3/3] examples: example showing use of callbacks John McNamara
2015-02-23 18:30 ` [dpdk-dev] [PATCH v6 0/3] DPDK ethdev callback support John McNamara
2015-02-23 18:30 ` [dpdk-dev] [PATCH v6 1/3] ethdev: rename callbacks field to link_intr_cbs John McNamara
2015-02-23 18:30 ` [dpdk-dev] [PATCH v6 2/3] ethdev: add optional rxtx callback support John McNamara
2015-02-23 18:30 ` [dpdk-dev] [PATCH v6 3/3] examples: example showing use of callbacks John McNamara
2015-02-23 23:39 ` [dpdk-dev] [PATCH v6 0/3] DPDK ethdev callback support Thomas Monjalon
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