[ovs-dev] [PATCH 0/2] Stop configuring '--socket-mem'/'--socket-limit' by default for DPDK if not requested.

[Kevin Traynor]

On 01/07/2021 18:46, Ilya Maximets wrote:
> On 6/30/21 10:48 PM, Rosemarie O'Riorden wrote:
>> From: Rosemarie O'Riorden <roriorde at redhat.com>
>>
>> Currently, there is a default value of 1024 for socket-mem if not
>> configured. socket-limit automatically takes on the value of socket-mem
>> unless otherwise specified. With these changes, memory allocation will
>> be dynamically managed by DPDK, meaning that by default,  no memory will
>> be pre-allocated on startup, and there will be no limit to how much
>> memory can be used. Either or both of these values can be set by the
>> user.
>>
>> The EAL arguments will look like this:
>>
>> - dpdk-socket-mem=<not set>, dpdk-socket-limit=<not set>
>>   current: "--scket-mem=1024,1024 --socket-limit=1024,1024"
>>   patch 1: ""
>>   patch 2: ""
>>
>> - dpdk-socket-mem=<MEM>, dpdk-socket-limit=<not set>
>>   current: "--scket-mem=MEM --socket-limit=MEM"
>>   patch 1: "--scket-mem=MEM --socket-limit=MEM"
>>   patch 2: "--scket-mem=MEM"
>>
>> - dpdk-socket-mem=<not set>, dpdk-socket-limit=<LIMIT>
>>   current: "--scket-mem=1024,1024 --socket-limit=LIMIT"
>>   patch 1: "--socket-limit=LIMIT"
>>   patch 2: "--socket-limit=LIMIT"
>>
>> - dpdk-socket-mem=<MEM>, dpdk-socket-limit=<LIMIT>
>>   current: "--scket-mem=MEM --socket-limit=LIMIT"
>>   patch 1: "--scket-mem=MEM --socket-limit=LIMIT"
>>   patch 2: "--scket-mem=MEM --socket-limit=LIMIT"
>>
>> Rosemarie O'Riorden (2):
>>   dpdk: Remove default values for socket-mem and limit.
>>   dpdk: Stop configuring socket-limit with the value of socket-mem.
>>
>>  Documentation/intro/install/dpdk.rst |  3 +--
>>  NEWS                                 |  4 ++++
>>  lib/dpdk.c                           |  6 +-----
>>  vswitchd/vswitch.xml                 | 13 ++++++-------
>>  4 files changed, 12 insertions(+), 14 deletions(-)
>>
> 
> Hi, Ian, everyone.
> 
> This is the series I barely mentioned on yesterday's public
> meeting.  It seems like a good thing to have in 2.16 release,
> but we definitely need an input from different sides on this
> kind of small, but user-visible change.
> 
> In general, I think, it's good to stop configuring these
> unnecessary defaults that only limit users.  1GB of memory is
> barely enough for a very small setup and, most likely, most
> of users are setting dpdk-socket-mem anyway and doesn't rely
> on the default option (AFAICT, Michael is checking this with
> OpenStack folks).  In any case, the upgrade path should not
> be hard, as it's enough to just set current values to the
> database before OVS upgrade.
> 
> Historically, it was there just to allow OVS run with DPDK
> "out-of-the-box" with a very minimal manual configuration,
> but current DPDK works without any memory configuration, so
> the original purpose of these defaults is not relevant anymore.
> 
> What do you think about this?
> 

I didn't review the code but the defaults looks good and more flexible.
At the same time there is still the option for specifying if a user
needs to.

> Best regards, Ilya Maximets.
>