Referee 1 *************************************************************************************

The manuscript describes an efficient parallel iterative method for GeoFEM using MPI and loop
directives. A complete analysis of the performance obtained is provided which shows the high
performance of the method used. I think the paper will make a great contribution to the journal,
the approach is very well described and the performance analysis is well done. Therefore, I
recommend the manuscript for publication providing the following minor changes are made.

* It is stated that to increase performance with a node or PE, loops should be sufficiently
long so that data or instructions can be efficiently pipelined through each PE. I agree
with this statement but I think a comment should be added on the effect of the length or
complexity of the body of the loops. The length or the complexity of the code within a
loop can be an important factor. If the body of a loop is too large the PEs may run out of
registers and/or may not be able to pipeline the instructions efficiently.

* An additional comment for Figure 9 is required, where apparently the speed-up is starting
to roll over when using more than 8 SMP-nodes, which I think is due to the small work
load per node when using small problem sizes.

* In Figure 11 showing the effect of the coefficient matrix storage method and re-ordering,
a decrease in performance is observed using the PDJDS/CM-RCM method when the
number of DOF exceed 10^6
. A comment on that should be added.

Referee 2 *************************************************************************************

The authors describe their efforts in achieving an efficient implementation for  iterative
solvers on SMP cluster architectures and present their results. This includes the use of
various known reordering techniques as well as the use of additive Schwarz methods to increase
the robustness of localized ILU(0)- or ICCG(0)-preconditioning. Technically, this paper is
very interesting. The figures are well done and aid the description of the various techniques.

My main concern about this paper is its use of the English language. The paper could be
greatly improved if someone who reads and writes English well could go over this paper and the
abstract with the authors and correct it. There are too many mistakes (with regard to grammar,
spelling, style, etc.) to write them all down in this report. It would take rewriting the
paper.
One reoccurring pattern is the omission of articles, 'a' or 'the',  (see also above title of
paper, which I corrected by adding articles). Also, it is important to check the spelling of
the names of the methods, such as Schwarz (not Schwartz), Cuthill-McKee (not Cuthil Mckee) ,
etc.