* 3-word attributes encoding @ 2009-03-30 14:37 Benny Halevy 2009-03-31 1:44 ` [pnfs] " J. Bruce Fields 0 siblings, 1 reply; 6+ messages in thread From: Benny Halevy @ 2009-03-30 14:37 UTC (permalink / raw) To: J. Bruce Fields; +Cc: Trond Myklebust, pNFS Mailing List, NFS list Bruce, As I mentioned in a reply to Trond, "nfsd41: support for 3-word long attribute bitmask" changes the server fattr encoding logic so it may send back a bitmap of length 1, even if the client sent a bitmap of length 2, if the second word of the bitmap is zero. Although I think this a valid implementation and other servers may do the same, it seems sub-optimal for the client's decoding of acl of fs_locations. It's pretty easy to revert to the old behavior on the server by always returning at least two bitmap words, or, if we keep the bitmap length, not just the val, in nfsd4_decode_bitmap we can return a bitmap of the same length in the reply. Let me know what you think... Other than that, git://linux-nfs.org/~bhalevy/linux-pnfs.git nfsd41-for-2.6.30 holds version 3 of the nfsd41 patchset, rebased onto your update for-2.6.30 branch, and with these cleanup patches squashed-in: [PATCH 1/3] SQUASHME: get callback minorversion from fore channel's [PATCH 2/3] SQUASHME: nfsd41: use nfsd4_cb_sequence for callback minorversion [PATCH 3/3] SQUASHME: Revert "sunrpc: add cl_private field to struct rpc_clnt" Benny ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [pnfs] 3-word attributes encoding 2009-03-30 14:37 3-word attributes encoding Benny Halevy @ 2009-03-31 1:44 ` J. Bruce Fields 2009-03-31 18:36 ` Benny Halevy 0 siblings, 1 reply; 6+ messages in thread From: J. Bruce Fields @ 2009-03-31 1:44 UTC (permalink / raw) To: Benny Halevy; +Cc: NFS list, pNFS Mailing List, Trond Myklebust On Mon, Mar 30, 2009 at 05:37:37PM +0300, Benny Halevy wrote: > Bruce, > > As I mentioned in a reply to Trond, > "nfsd41: support for 3-word long attribute bitmask" > changes the server fattr encoding logic so it may send > back a bitmap of length 1, even if the client sent a > bitmap of length 2, if the second word of the bitmap > is zero. Although I think this a valid implementation > and other servers may do the same, it seems sub-optimal > for the client's decoding of acl of fs_locations. "suboptimal" means it does some extra memcpy'ing? > It's pretty easy to revert to the old behavior on the server > by always returning at least two bitmap words, or, if we > keep the bitmap length, not just the val, in nfsd4_decode_bitmap > we can return a bitmap of the same length in the reply. Odd thing to have to do, but OK. --b. > > Let me know what you think... > > Other than that, > git://linux-nfs.org/~bhalevy/linux-pnfs.git nfsd41-for-2.6.30 > holds version 3 of the nfsd41 patchset, rebased onto your > update for-2.6.30 branch, and with these cleanup patches squashed-in: > > [PATCH 1/3] SQUASHME: get callback minorversion from fore channel's > [PATCH 2/3] SQUASHME: nfsd41: use nfsd4_cb_sequence for callback minorversion > [PATCH 3/3] SQUASHME: Revert "sunrpc: add cl_private field to struct rpc_clnt" > > Benny > _______________________________________________ > pNFS mailing list > pNFS@linux-nfs.org > http://linux-nfs.org/cgi-bin/mailman/listinfo/pnfs ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [pnfs] 3-word attributes encoding 2009-03-31 1:44 ` [pnfs] " J. Bruce Fields @ 2009-03-31 18:36 ` Benny Halevy 2009-03-31 19:42 ` J. Bruce Fields 0 siblings, 1 reply; 6+ messages in thread From: Benny Halevy @ 2009-03-31 18:36 UTC (permalink / raw) To: J. Bruce Fields; +Cc: NFS list, pNFS Mailing List, Trond Myklebust On Mar. 31, 2009, 4:44 +0300, "J. Bruce Fields" <bfields@fieldses.org> wrote: > On Mon, Mar 30, 2009 at 05:37:37PM +0300, Benny Halevy wrote: >> Bruce, >> >> As I mentioned in a reply to Trond, >> "nfsd41: support for 3-word long attribute bitmask" >> changes the server fattr encoding logic so it may send >> back a bitmap of length 1, even if the client sent a >> bitmap of length 2, if the second word of the bitmap >> is zero. Although I think this a valid implementation >> and other servers may do the same, it seems sub-optimal >> for the client's decoding of acl of fs_locations. > > "suboptimal" means it does some extra memcpy'ing? Yes, I believe so. > >> It's pretty easy to revert to the old behavior on the server >> by always returning at least two bitmap words, or, if we >> keep the bitmap length, not just the val, in nfsd4_decode_bitmap >> we can return a bitmap of the same length in the reply. > > Odd thing to have to do, but OK. --b. What would you prefer to do? Revert to old behavior by returning at least two bitmap words or use the args bitmap length for encoding the res? Benny > >> Let me know what you think... >> >> Other than that, >> git://linux-nfs.org/~bhalevy/linux-pnfs.git nfsd41-for-2.6.30 >> holds version 3 of the nfsd41 patchset, rebased onto your >> update for-2.6.30 branch, and with these cleanup patches squashed-in: >> >> [PATCH 1/3] SQUASHME: get callback minorversion from fore channel's >> [PATCH 2/3] SQUASHME: nfsd41: use nfsd4_cb_sequence for callback minorversion >> [PATCH 3/3] SQUASHME: Revert "sunrpc: add cl_private field to struct rpc_clnt" >> >> Benny >> _______________________________________________ >> pNFS mailing list >> pNFS@linux-nfs.org >> http://linux-nfs.org/cgi-bin/mailman/listinfo/pnfs ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [pnfs] 3-word attributes encoding 2009-03-31 18:36 ` Benny Halevy @ 2009-03-31 19:42 ` J. Bruce Fields 2009-03-31 20:00 ` Benny Halevy 0 siblings, 1 reply; 6+ messages in thread From: J. Bruce Fields @ 2009-03-31 19:42 UTC (permalink / raw) To: Benny Halevy; +Cc: NFS list, pNFS Mailing List, Trond Myklebust On Tue, Mar 31, 2009 at 09:36:08PM +0300, Benny Halevy wrote: > On Mar. 31, 2009, 4:44 +0300, "J. Bruce Fields" <bfields@fieldses.org> wrote: > > On Mon, Mar 30, 2009 at 05:37:37PM +0300, Benny Halevy wrote: > >> Bruce, > >> > >> As I mentioned in a reply to Trond, > >> "nfsd41: support for 3-word long attribute bitmask" > >> changes the server fattr encoding logic so it may send > >> back a bitmap of length 1, even if the client sent a > >> bitmap of length 2, if the second word of the bitmap > >> is zero. Although I think this a valid implementation > >> and other servers may do the same, it seems sub-optimal > >> for the client's decoding of acl of fs_locations. > > > > "suboptimal" means it does some extra memcpy'ing? > > Yes, I believe so. > > > > >> It's pretty easy to revert to the old behavior on the server > >> by always returning at least two bitmap words, or, if we > >> keep the bitmap length, not just the val, in nfsd4_decode_bitmap > >> we can return a bitmap of the same length in the reply. > > > > Odd thing to have to do, but OK. --b. > > What would you prefer to do? > Revert to old behavior by returning at least two bitmap words > or use the args bitmap length for encoding the res? Whichever requires the least code? I don't know. If the client really needs this, then it needs to be agreed on by more than just the linux server. It's unfortunate if making this arbitrary undocumented choice of result encoding makes a significant difference to the client's performance. --b. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [pnfs] 3-word attributes encoding 2009-03-31 19:42 ` J. Bruce Fields @ 2009-03-31 20:00 ` Benny Halevy 2009-04-01 16:19 ` J. Bruce Fields 0 siblings, 1 reply; 6+ messages in thread From: Benny Halevy @ 2009-03-31 20:00 UTC (permalink / raw) To: J. Bruce Fields; +Cc: NFS list, pNFS Mailing List, Trond Myklebust On Mar. 31, 2009, 22:42 +0300, "J. Bruce Fields" <bfields@fieldses.org> wrote: > On Tue, Mar 31, 2009 at 09:36:08PM +0300, Benny Halevy wrote: >> On Mar. 31, 2009, 4:44 +0300, "J. Bruce Fields" <bfields@fieldses.org> wrote: >>> On Mon, Mar 30, 2009 at 05:37:37PM +0300, Benny Halevy wrote: >>>> Bruce, >>>> >>>> As I mentioned in a reply to Trond, >>>> "nfsd41: support for 3-word long attribute bitmask" >>>> changes the server fattr encoding logic so it may send >>>> back a bitmap of length 1, even if the client sent a >>>> bitmap of length 2, if the second word of the bitmap >>>> is zero. Although I think this a valid implementation >>>> and other servers may do the same, it seems sub-optimal >>>> for the client's decoding of acl of fs_locations. >>> "suboptimal" means it does some extra memcpy'ing? >> Yes, I believe so. >> >>>> It's pretty easy to revert to the old behavior on the server >>>> by always returning at least two bitmap words, or, if we >>>> keep the bitmap length, not just the val, in nfsd4_decode_bitmap >>>> we can return a bitmap of the same length in the reply. >>> Odd thing to have to do, but OK. --b. >> What would you prefer to do? >> Revert to old behavior by returning at least two bitmap words >> or use the args bitmap length for encoding the res? > > Whichever requires the least code? I don't know. The former seems simpler to code. > > If the client really needs this, then it needs to be agreed on by more > than just the linux server. It's unfortunate if making this arbitrary > undocumented choice of result encoding makes a significant difference to > the client's performance. I think that currently it affects only getacl and I have no measurements of to what extent the effect of performance is. Benny > > --b. ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [pnfs] 3-word attributes encoding 2009-03-31 20:00 ` Benny Halevy @ 2009-04-01 16:19 ` J. Bruce Fields 0 siblings, 0 replies; 6+ messages in thread From: J. Bruce Fields @ 2009-04-01 16:19 UTC (permalink / raw) To: Benny Halevy; +Cc: NFS list, pNFS Mailing List, Trond Myklebust On Tue, Mar 31, 2009 at 11:00:50PM +0300, Benny Halevy wrote: > On Mar. 31, 2009, 22:42 +0300, "J. Bruce Fields" <bfields@fieldses.org> wrote: > > On Tue, Mar 31, 2009 at 09:36:08PM +0300, Benny Halevy wrote: > >> On Mar. 31, 2009, 4:44 +0300, "J. Bruce Fields" <bfields@fieldses.org> wrote: > >>> On Mon, Mar 30, 2009 at 05:37:37PM +0300, Benny Halevy wrote: > >>>> Bruce, > >>>> > >>>> As I mentioned in a reply to Trond, > >>>> "nfsd41: support for 3-word long attribute bitmask" > >>>> changes the server fattr encoding logic so it may send > >>>> back a bitmap of length 1, even if the client sent a > >>>> bitmap of length 2, if the second word of the bitmap > >>>> is zero. Although I think this a valid implementation > >>>> and other servers may do the same, it seems sub-optimal > >>>> for the client's decoding of acl of fs_locations. > >>> "suboptimal" means it does some extra memcpy'ing? > >> Yes, I believe so. > >> > >>>> It's pretty easy to revert to the old behavior on the server > >>>> by always returning at least two bitmap words, or, if we > >>>> keep the bitmap length, not just the val, in nfsd4_decode_bitmap > >>>> we can return a bitmap of the same length in the reply. > >>> Odd thing to have to do, but OK. --b. > >> What would you prefer to do? > >> Revert to old behavior by returning at least two bitmap words > >> or use the args bitmap length for encoding the res? > > > > Whichever requires the least code? I don't know. > > The former seems simpler to code. > > > > > If the client really needs this, then it needs to be agreed on by more > > than just the linux server. It's unfortunate if making this arbitrary > > undocumented choice of result encoding makes a significant difference to > > the client's performance. > > I think that currently it affects only getacl and I have no measurements > of to what extent the effect of performance is. I'd rather just not worry about it. If it turns out to be a problem then we can try to figure out a less fragile solution. --b. ^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2009-04-01 16:19 UTC | newest] Thread overview: 6+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2009-03-30 14:37 3-word attributes encoding Benny Halevy 2009-03-31 1:44 ` [pnfs] " J. Bruce Fields 2009-03-31 18:36 ` Benny Halevy 2009-03-31 19:42 ` J. Bruce Fields 2009-03-31 20:00 ` Benny Halevy 2009-04-01 16:19 ` J. Bruce Fields
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