ping.. ________________________________ From: Jerin Jacob Kollanukkaran Sent: Thursday, June 27, 2019 3:04:58 PM To: Burakov, Anatoly; Vamsi Krishna Attunuru; [email protected] Cc: [email protected]; [email protected]; [email protected] Subject: RE: [dpdk-dev] [PATCH v6 0/4] add IOVA = VA support in KNI
> -----Original Message----- > From: Burakov, Anatoly <[email protected]> > Sent: Tuesday, June 25, 2019 7:09 PM > To: Jerin Jacob Kollanukkaran <[email protected]>; Vamsi Krishna Attunuru > <[email protected]>; [email protected] > Cc: [email protected]; [email protected]; > [email protected] > Subject: Re: [dpdk-dev] [PATCH v6 0/4] add IOVA = VA support in KNI > > On 25-Jun-19 12:30 PM, Burakov, Anatoly wrote: > > On 25-Jun-19 12:15 PM, Jerin Jacob Kollanukkaran wrote: > >>> -----Original Message----- > >>> From: dev <[email protected]> On Behalf Of Burakov, Anatoly > >>> Sent: Tuesday, June 25, 2019 3:30 PM > >>> To: Vamsi Krishna Attunuru <[email protected]>; [email protected] > >>> Cc: [email protected]; [email protected]; > >>> [email protected] > >>> Subject: Re: [dpdk-dev] [PATCH v6 0/4] add IOVA = VA support in KNI > >>> > >>> On 25-Jun-19 4:56 AM, [email protected] wrote: > >>>> From: Vamsi Attunuru <[email protected]> > >>>> > >>>> ---- > >>>> V6 Changes: > >>>> * Added new mempool flag to ensure mbuf memory is not scattered > >>>> across page boundaries. > >>>> * Added KNI kernel module required PCI device information. > >>>> * Modified KNI example application to create mempool with new > >>>> mempool flag. > >>>> > >>> Others can chime in, but my 2 cents: this reduces the usefulness of > >>> KNI because it limits the kinds of mempools one can use them with, > >>> and makes it so that the code that works with every other PMD > >>> requires changes to work with KNI. > >> > >> # One option to make this flag as default only for packet mempool(not > >> allow allocate on page boundary). > >> In real world the overhead will be very minimal considering Huge page > >> size is 1G or 512M # Enable this flag explicitly only IOVA = VA mode > >> in library. Not need to expose to application # I don’t think, there > >> needs to be any PMD specific change to make KNI with IOVA = VA mode # > >> No preference on flags to be passed by application vs in library. > >> But IMO this change would be > >> needed in mempool support KNI in IOVA = VA mode. > >> > > > > I would be OK to just make it default behavior to not cross page > > boundaries when allocating buffers. This would solve the problem for > > KNI and for any other use case that would rely on PA-contiguous > > buffers in face of IOVA as VA mode. > > > > We could also add a flag to explicitly allow page crossing without > > also making mbufs IOVA-non-contiguous, but i'm not sure if there are > > use cases that would benefit from this. > > On another thought, such a default would break 4K pages in case for packets > bigger than page size (i.e. jumbo frames). Should we care? The hugepage size will not be 4K. Right? Olivier, As a maintainer any thoughts of exposing/not exposing the new mepool flag to Skip the page boundaries? All, Either option is fine, Asking for feedback to processed further?
