REFEREE'S REPORT Concurrency and Computation:Practice and Experience --------------------------------------------------------------------------- A: General Information Please return to: Geoffrey C. Fox Electronically Preferred fox@csit.fsu.edu Concurrency and Computation: Practice and Experience Computational Science and Information Technology Florida State University 400 Dirac Science Library Tallahassee Florida 32306-4130 Office FAX 850-644-0098 Office Phone 850-644-4587 but best is cell phone 3152546387 Please fill in Summary Conclusions (Sec. C) and details as appropriate in Secs. D, E and F. B: Refereeing Philosophy We encourage a broad range of readers and contributors. Please judge papers on their technical merit and separate comments on this from those on style and approach. Keep in mind the strong practical orientation that we are trying to give the journal. Note that the forms attached provide separate paper for comments that you wish only the editor to see and those that both the editor and author receive. Your identity will of course not be revealed to the author. C: Paper and Referee Metadata * Paper Number Cnnn: C516 * Date: July 15, 2001 * Paper Title: An Analysis of VI Architecture Primitives in Support of Parallel and Distributed Communication * Author(s): Andrew Begel, Philip Buonadonna, David Culler, David Gay * Referee: Thomas Sterling, tron@cacr.caltech.edu * Address: California Institute of Technology Pasadena, California Referee Recommendations. Please indicate overall recommendations here, and details in following sections. X 1. publish as is 2. accepted provided changes suggested are made 3. reject D: Referee Comments (For Editor Only) I hope the authors pay attention to at least some of the comments below. The paper is pretty good but it is tough wading through parts of it and therefore does not make for effective communication. I suggest you push for some more figures that can better illustrate some of the ideas. E: Referee Comments (For Author and Editor) Overall the paper is very good, well written, and of interest to the community. I recommend that the paper be published essentially as is. Several typo errors were discovered and these are noted below in section F. Some comments are provided here which the authors might consider in developing their final version of the paper. The paper is very ambitious and could have be written a two to four separate papers that could easily have stood on their own. There are many degrees of freedom that are being discussed at the same time and several systems that have to be understood (e.g. AM, Split-C, VIA, Infiniband, etc.) and described in a finite space. There are places where the material may be too succinct to give adequate coverage of necessary data or too dense to be easily assimilated by the reader. In a number of cases, the authors assume the reader knows background information that may not be warranted and at other times information is provided later in the paper that could have been useful earlier on. Finally, the discussion about Infiniband is not required for this paper and is too brief to provide a meaningful foundation for understanding. Some specifics follow: In section 2, the doorbell mechanism is mentioned but only much later defined. Also here, the LANai 7 processor is mentioned without informing the reader that it is associated with Myrinet. Later this is cleared up. Section 3.1 would truly benefit from a pair of diagrams showing the general interaction and state of communication and perhaps of the (somewhat simplified) control state transitions. This is also true for sections 4.1 and 4.2 to help the reader picture what is going on. In Table 1 you do not identify LANai from Myricom while both Giganet (the name has changed by the way) and Compaq are mentioned. In the last paragraph of section 3.2 "receive credits" and "NAKs" are not defined but perhaps should be. How sensitive are the timings and rates of Table 1 to message length. In the second paragraph of section 3.3, a subjective statement is made without justification in support of the LANai chip in spite of its lower performance. I think the description of the VIA operations should be first introduced in section 3.1 instead of waiting until Tables 3 & 4 several sections later to show them to the reader. The caption for Table 2 refers to both AM and Split-C but the table itself seems to convey data only about AM; perhaps I am missing something here. In section 9, a statement is made that indicates that large scale systems are enabled by these technologies. But the body of the paper does not talk about scalability and this statement can't be supported by the data presented. F: Presentation Changes [section 3.1, 3rd paragraph, 2nd sentence] "... posts it into appropriate ..." -> "... posts it into -an- appropriate ..." [section 3.1, 4th paragraph, 5th sentence] "... can be be piggybacked ..." -> "... can be piggybacked ..." [section 3.2, 1st paragraph, 1st sentence] "... a brief overview the infiniband ..." -> "... a brief overview -of- the ..." [section 4.1, 3rd paragraph, 6th sentence] "... includes of a pair ..." -> "... includes a pair ..." [section 6, 1st bullet] "... read operation in an optional ..." -> "... read operation -is- an optional ..."