Add OmpSs-2 simple example

ompss2/README.md

@@ -0,0 +1,57 @@
+# OmpSs-2 environment
+
+This example shows how to include the LLVM compiler to build OmpSs-2 programs
+with the new NODES and nOS-V runtime. The package `clangOmpss2Nodes` already
+sets all the needed variables to locate the right runtime.
+
+Run `nix develop` then `make` to build the `hello` program:
+
+    apex% nix develop
+    apex$ make
+    clang -fompss-2    hello.c   -o hello
+    apex$ ./hello
+    hello from task 1
+    hello from task 0
+    hello from task 2
+    hello from task 3
+    hello from task 4
+    hello from task 7
+    hello from task 8
+    hello from task 6
+    hello from task 9
+    hello from task 5
+
+You can use `make trace` to run the hello program with instrumentation and
+generate an ovni trace that is then converted to paraver:
+
+    apex$ make trace
+    rm -rf ovni/
+    NOSV_CONFIG_OVERRIDE="instrumentation.version=ovni" NOSV_APPID=1 ./hello
+    hello from task 1
+    hello from task 0
+    hello from task 3
+    hello from task 4
+    hello from task 5
+    hello from task 6
+    hello from task 2
+    hello from task 8
+    hello from task 7
+    hello from task 9
+    ovniemu ovni/
+    ovniemu: INFO: loaded 58 streams
+    ovniemu: INFO: sorting looms by name
+    ovniemu: INFO: loaded 1 looms, 1 processes, 58 threads and 56 cpus
+    ovniemu: INFO: generated with libovni version 1.13.0 commit 0643266
+    ovniemu: INFO: the following 2 models are enabled:
+    ovniemu: INFO:      ovni 1.1.0 'O' (18 events)
+    ovniemu: INFO:      nosv 2.6.0 'V' (64 events)
+    ovniemu: INFO: emulation starts
+    ovniemu: INFO: apex.nosv-u1880-p598308 burst stats: median/avg/max =  77/ 81/333 ns
+    ovniemu: WARN: ignoring old event OCn
+    ovniemu: INFO: 100.0% done at avg 42 kev/s
+    ovniemu: INFO: processed 711 input events in 0.02 s
+    ovniemu: INFO: writing traces to disk, please wait
+    ovniemu: INFO: emulation finished ok
+    ls -l ovni/*.prv
+    -rw-r--r-- 1 rarias Computational 48224 Feb  4 11:52 ovni/cpu.prv
+    -rw-r--r-- 1 rarias Computational 33689 Feb  4 11:52 ovni/thread.prv