* Masahiro Tamori (masahiro.tamori@xxxxxxxxx) wrote: > 2009/3/21 Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>: > > * Masahiro Tamori (masahiro.tamori@xxxxxxxxx) wrote: [...] > >> Our customer will use NFS to store trace data not storage device for > >> embedded devices. > >> Since newer lttng use splice() even if NFS can not support splice(), > >> I create a patch to support to mmap of ltt-relay-alloc. > >> [...] > >> ltt-relay-alloc mmap support > >> > >> Splice syscall does not support NFS. We can not save trace data to > >> NFS directory. If this feature is enabled, you can use mmap() > >> instead of splice(). > >> > > > > > > Hi Masahiro, > > > > Maybe we should consider implementing splice() support in NFS instead ? > > > > I removed the mmap support from the ltt-relay-alloc files because splice > > is more efficient and does not require to vmap the pages. Unless there > > is a strong argument telling what in NFS makes it impossible to > > implement splice(), I don't really see the gain in putting back the > > old mmap() mechanism we had. > > > > Maybe the NFS people will have some information about this ? > > > > Thanks, > > > > Mathieu > > > > Hello Mathieu, > > I think that the best solution is NFS can support splice() even if > it cannot zero copy. > > The splice() will be used by any other tools, hence NFS should support > it sooner or later. > > If technical issue is remained to support splice() in NFS, > we should support mmap in LTTng until the problem is resolved. > Embedded people will want to use LTTng with NFS, > though this is a bad choice. > > Thank you, > Masahiro Tamori > There was a LKML thread on NFS splice support back in 2006 : http://lkml.indiana.edu/hypermail/linux/kernel/0603.3/2102.html I don't know what happened with this ? I have tested NFS v2 and v3 and have seen they do not support splice, but haven't tested NFSv4. Mathieu -- Mathieu Desnoyers OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68 -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
