On 3 Feb 2010 at 23:52, Jack Z wrote: > Hi Mike, > > Thank you for being so helpful! > > > > > What are you working on btw? > > I observed a throughput degradation of open-iscsi over long RTT links. > I'm trying to understand the nature of this performance degradation > and possibly come up with some solution.
The obvious two solutions are: 1) sending larger packets (which is unrealistic at some point) 2) sending more unconfirmed packets (which is also unrealistic at some point) 3) Moving closer ;-) Ulrich > > Thanks again, > Jack > > > On Feb 3, 2:36 am, Mike Christie <[email protected]> wrote: > > On 02/02/2010 09:57 PM, Jack Z wrote: > > > > > > > > > > > > > Hi all, > > > > > In the source code of ver 2.0.871 there's a struct > > > > > struct iscsi_segment { > > > unsigned char *data; > > > unsigned int size; > > > unsigned int copied; > > > unsigned int total_size; > > > unsigned int total_copied; > > > > > ...... > > > > > iscsi_segment_done_fn_t *done; > > > }; > > > > > My understanding is that "copied" is how many bytes are sent out in > > > the last round and "total_copied" is an accumulative value of how many > > > bytes have been sent out. Is that correct? > > > > > And what do "size" and "total_size" mean respectively? > > > > The segment represents the header or data segment that needs to be sent. > > That segment has a total_size which is all the bytes that need to be > > sent/recvd for it to be completely sent. The segment->size is what we > > are currently trying to send/recv for that segment. So we could have a > > data segment of 128K (so we want to send/recv 128K bytes), but we end up > > sending that down a page at a time to the net layer. So > > segment->totoal_size would be 128K and segment->size would be 4K (page > > size on x86 would be 4K). > > > > > > > > > Thank you very much! Any help would be highly appreciated. > > -- > You received this message because you are subscribed to the Google Groups > "open-iscsi" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/open-iscsi?hl=en. > -- You received this message because you are subscribed to the Google Groups "open-iscsi" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/open-iscsi?hl=en.
