Changes between Version 8 and Version 9 of ParallelismPerformances

Timestamp:

2012-10-04T16:45:08+02:00 (12 years ago)

Author:

dsolyga

Comment:

--

ParallelismPerformances

@@ -101 +101 @@
  * Possible explanations : bug in IOIPSL, bug in the parallelization, bad use of Vampir?
  * To investigate : why flinopen takes so much time? Test with previous ORCHIDEE tag and IOIPSL tag (DONE, see above). Study the influence of th file LoadBalance.dat.  
+
+
+== INVESTIGATION ON INPUT PROBLEMS (October 2012) ==
+
+ * After some tests, I found the line which causes the problem :
+{{{
+   iret = NF90_GET_VAR (fid,vid,vec_tmp,start=(/ 1 /),count=(/ ttm /))
+}}}
+  I put some VAMPIR marks before and after the line like this (I replace the original memory allocation for vec_tmp by a local array vec_tmp_ttm) :
+
+{{{
+    VT_USER_START('NF90_GET_VAR')
+    iret = NF90_GET_VAR (fid,vid,vec_tmp_ttm,start=(/ 1 /),count=(/ ttm /))
+    VT_USER_END('NF90_GET_VAR')
+}}}
+and I obtain the following figure :
+[[Image(http://dods.ipsl.jussieu.fr/orchidee/WIKI/VAMPIR_RESULTS_PATCH/BUG_FLINCOM_NF90_GET_VAR.png,70%)]]
+
+
+When I replace this netcdf instruction by an array initialization for ncc forcing :
+
+{{{
+    vec_tmp_ttm = (/ (iv, iv = 1,1461) /)
+}}}
+I obtain the following results :
+[[Image(http://dods.ipsl.jussieu.fr/orchidee/WIKI/VAMPIR_RESULTS_PATCH/MODIF_FLINCOM_GET_VAR_16PROCS.png,70%)]]
+The time used is divided by 3 !
+
+=== '''QUESTIONS : ''' ===
+
+ * Problem from netcdf library ? By default, I was using 3.6.3. Should test another nectdf version.(To be done)
+ * Problem from disk on Curie ? Try a run on Obelix by using the instruction CALL cpu_time (Vampir cannot be used on Obelix).(To be done)
+ 
+