On Fri, Jan 10, 2014 at 11:43:12AM -0800, Joe Stringer wrote: > Previously when dumping flows from the datapath, callers of > dpif_flow_dump_next() could specify whether they wish to fetch the > actions for a flow. Depending on the datapath implementation, these may > be fetched at no performance cost or may require additional resources > to fetch. > > The most frequent caller of this function is the flow_dumper, which > does not care about fetching actions. This patch removes the actions > parameters from dpif_flow_dump_next(), to provide more consistent > performance in this common use case. If callers wish to get the actions > for a flow, they can make a separate call to flow_get(). > > Signed-off-by: Joe Stringer <[email protected]>
I think that this is a reasonable thing to do, but if I understand what's going on in the series, I don't think I agree with the rationale given here. I believe that "to provide more consistent performance" implies "make getting the actions slow for everyone, even if it could be done quickly." As far as I can tell that's an undesirable side effect, not a benefit. My reading is that the desirable side effect here is that it gets rid of internal state in dumper implementations that would otherwise have to become per-thread state in upcoming patches. It still makes getting the actions slow for everyone, but that's justifiable on the grounds that it doesn't matter to any existing users. Is that right? Thanks, Ben. _______________________________________________ dev mailing list [email protected] http://openvswitch.org/mailman/listinfo/dev
