From: "Varghese, Vipin" <vipin.varghese@intel.com>
To: Stephen Hemminger <stephen@networkplumber.org>
Cc: "olivier.matz@6wind.com" <olivier.matz@6wind.com>,
"Pattan, Reshma" <reshma.pattan@intel.com>,
"Wiles, Keith" <keith.wiles@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>,
"Padubidri, Sanjay A" <sanjay.padubidri@intel.com>
Subject: Re: [dpdk-dev] [PATCH v1 1/2] lib/ring: add enqueue-dequeue callabck
Date: Mon, 10 Jun 2019 05:07:45 +0000 [thread overview]
Message-ID: <4C9E0AB70F954A408CC4ADDBF0F8FA7D4D36601D@BGSMSX101.gar.corp.intel.com> (raw)
In-Reply-To: <20190606124927.1a369d5b@hermes.lan>
Hi Stephen,
snipped
> NAK
> What is the use case for this?
Use cases:
- allow user to investigate the contents pre-enqueue.
- allow user to investigate the contents post-dequeue.
- modify pre-enqueue and post-dequeue stage content.
- investigate PMD meta data.
Rings are one of the most used elements of DPDK
> and anything like this will have performance impact.
Based on the current testing with 10G, the impact with callback handlers enabled with no or one has less than 0.1% with SP-SC. I will test for more cases like SP-MC, MP-SC, and MP-MC.
>
> And as DPDK goes to more of distribution model, all features have to be enabled.
>
>
> Also, this looks like a problem:
> +struct rte_ring_callback {
> + TAILQ_ENTRY(rte_ring_callback) next; /* Callbacks list */
> + rte_ring_cb_fn cb_fn; /* Callback address */
> + void *cb_arg; /* Parameter for callback */
> + uint32_t active; /* Callback is executing */
>
> The active element is likely updated in one thread and queried in another it needs
> to be volatile, or better yet an atomic to ensure memory ordering.
Yes, thanks you for pointing this out, Let me correct the same.
next prev parent reply other threads:[~2019-06-10 5:07 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-06 18:33 Vipin Varghese
2019-06-06 18:33 ` [dpdk-dev] [PATCH v1 2/2] examples/packet_ordering: add ring callback Vipin Varghese
2019-06-06 19:49 ` [dpdk-dev] [PATCH v1 1/2] lib/ring: add enqueue-dequeue callabck Stephen Hemminger
2019-06-07 9:30 ` Bruce Richardson
2019-06-10 5:14 ` Varghese, Vipin
2019-06-07 10:45 ` Ananyev, Konstantin
2019-06-10 5:16 ` Varghese, Vipin
2019-06-10 5:07 ` Varghese, Vipin [this message]
2019-06-07 6:03 ` Honnappa Nagarahalli
2019-06-10 5:12 ` Varghese, Vipin
2019-06-11 4:17 ` Honnappa Nagarahalli
2019-07-04 5:04 ` Varghese, Vipin
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