[ovs-dev] [PATCH v1] doc: Remove experimental tag for SMC cache.

Wang, Yipeng1 yipeng1.wang at intel.com
Wed Jul 17 18:51:25 UTC 2019

>-----Original Message-----
>From: Stokes, Ian
>Sent: Thursday, July 4, 2019 3:40 AM
>To: Ilya Maximets <i.maximets at samsung.com>; Wang, Yipeng1 <yipeng1.wang at intel.com>; dev at openvswitch.org; Ben Pfaff
><blp at ovn.org>
>Subject: Re: [PATCH v1] doc: Remove experimental tag for SMC cache.
>On 7/4/2019 11:12 AM, Ilya Maximets wrote:
>> On 03.07.2019 19:58, Ian Stokes wrote:
>>> On 6/27/2019 12:44 PM, Yipeng Wang wrote:
>>>> SMC cache was introduced in 2.10 with experimental tag.
>>>> SMC cache is a layer of software cache located after EMC
>>>> cache. The purpose is to improve the performance of use
>>>> cases that many flows missing the EMC cache.
>>>> One can enable SMC cache using smc-enable=true option.
>>> Thanks for this Yipeng.
>>> I'd raised the topic of removing the experimental tag at the community call previously.
>>> I guess two aspects were called out that form part of the litmus test for when the tag should be removed.
>>> 1. Is the feature in use in common/commercial use?
>>> 2. Are there any to-dos or known bugs to be resolved?
>>> WRT point 1, I do believe it has been used/tested in commercial deployments and has been benchmarked against realistic
>deployments with positive results over EMC (except when there is only a small number of flows). I believe this was even presented
>by Red Hat at the OVS conference last year, so this is encouraging.
>>> WRT to known bugs I'm not aware of any outstanding. There have been a handful of patches upstreamed since 2.10 to address
>some minor issues.
>>> I think it's ok to remove this tag for the 2.12 release.
>>> Would be interested to hear others thoughts?
>> Hi, Ian and Yipeng.
>> SMC seems stable enough now. Since fixing one major bug last year I
>> didn't noticed about new issues, however I didn't try to use it in
>> long-living setups.
>> This change doesn't enable SMC by default, so it's totally OK for
>> me to remove the experimental tag. This way we'll, probably, have
>> more users of this feature and subsequently more testing that will
>> allow us to enable it by default for a next releases.
>Thanks Ilya, I agree, its seems to be a natural first step before
>replacing EMC.
>> So, idea is good. One comment inline for the patch itself. And
>> rebase is needed also.
>> Best regards, Ilya Maximets.
>>> Regards
>>> Ian
>>>> Signed-off-by: Yipeng Wang <yipeng1.wang at intel.com>
>>>> ---
>>>>    Documentation/topics/dpdk/bridge.rst | 4 ++--
>>>>    NEWS                                 | 1 +
>>>>    2 files changed, 3 insertions(+), 2 deletions(-)
>>>> diff --git a/Documentation/topics/dpdk/bridge.rst b/Documentation/topics/dpdk/bridge.rst
>>>> index a3ed926..71e1af6 100644
>>>> --- a/Documentation/topics/dpdk/bridge.rst
>>>> +++ b/Documentation/topics/dpdk/bridge.rst
>>>> @@ -117,7 +117,7 @@ It is also possible to enable/disable EMC on per-port basis using::
>>>>    For more information on the EMC refer to :doc:`/intro/install/dpdk` .
>>>>      -SMC cache (experimental)
>>>> +SMC cache
>>>>    -------------------------
>> Above line should be shortened according to the new section name
>> to be rST compliant, otherwise it will trigger a warning/error
>> while docs generation.
[Wang, Yipeng] Fixed in V2.
>>>>      SMC cache or signature match cache is a new cache level after EMC cache.
>>>> @@ -125,7 +125,7 @@ The difference between SMC and EMC is SMC only stores a signature of a flow
>>>>    thus it is much more memory efficient. With same memory space, EMC can store 8k
>>>>    flows while SMC can store 1M flows. When traffic flow count is much larger than
>>>>    EMC size, it is generally beneficial to turn off EMC and turn on SMC. It is
>>>> -currently turned off by default and an experimental feature.
>>>> +currently turned off by default.
>>>>      To turn on SMC::
>>>>    diff --git a/NEWS b/NEWS
>>>> index 2f8171f..bf99295 100644
>>>> --- a/NEWS
>>>> +++ b/NEWS
>>>> @@ -29,6 +29,7 @@ Post-v2.11.0
>>>>         * New action "check_pkt_len".
>>>>         * Port configuration with "other-config:priority-tags" now has a mode
>>>>           that retains the 802.1Q header even if VLAN and priority are both zero.
>>>> +     * Removed experimental tag for SMC cache.
>>>>       - OVSDB:
>>>>         * OVSDB clients can now resynchronize with clustered servers much more
>>>>           quickly after a brief disconnection, saving bandwidth and CPU time.

[Wang, Yipeng]
Thank you both for the comment! I rebased and posted V2.


More information about the dev mailing list