PSM2 is the only valid implementation for OmniPath (OPA).  UCX also
supports OmniPath, but it does so via Verbs, thus getting much lower
performance (typically 3 GiB/s instead of 10 GiB/s).

To work around that, give the mtl_psm2 component a higher priority
than the pml_ucx component.

See <https://www.mail-archive.com/users@lists.open-mpi.org/msg33581.html>.

--- openmpi-4.0.2/ompi/mca/mtl/psm2/mtl_psm2_component.c	2019-11-15 17:06:15.142076840 +0100
+++ openmpi-4.0.2/ompi/mca/mtl/psm2/mtl_psm2_component.c	2019-11-15 17:06:22.242009379 +0100
@@ -126,7 +126,7 @@ ompi_mtl_psm2_component_register(void)
         setenv("PSM2_DEVICES", "self,shm", 0);
     }
 
-    param_priority = 40;
+    param_priority = 55;
     (void) mca_base_component_var_register (&mca_mtl_psm2_component.super.mtl_version,
                                             "priority", "Priority of the PSM2 MTL component",
                                             MCA_BASE_VAR_TYPE_INT, NULL, 0, 0,

Likewise for PSM: we want InfiniPath to be taken care of by PSM, not by UCX,
since UCX achieves worse performance.

--- openmpi-4.0.2/ompi/mca/mtl/psm/mtl_psm_component.c
+++ openmpi-4.0.2/ompi/mca/mtl/psm/mtl_psm_component.c
@@ -92,7 +92,7 @@ ompi_mtl_psm_component_register(void)
 
 
     /* set priority high enough to beat ob1's default */
-    param_priority = 30;
+    param_priority = 54;
     (void) mca_base_component_var_register (&mca_mtl_psm_component.super.mtl_version,
                                             "priority", "Priority of the PSM MTL component",
                                             MCA_BASE_VAR_TYPE_INT, NULL, 0, 0,
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<div class='path'>path: <a href='/guix/log/?id=290ac5cd1e67d99b4d704603c1559dfb72f542c2'>root</a>/<a href='/guix/log/gnu?id=290ac5cd1e67d99b4d704603c1559dfb72f542c2'>gnu</a>/<a href='/guix/log/gnu/services?id=290ac5cd1e67d99b4d704603c1559dfb72f542c2'>services</a>/<a href='/guix/log/gnu/services/ci.scm?id=290ac5cd1e67d99b4d704603c1559dfb72f542c2'>ci.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/services/ci.scm?id=290ac5cd1e67d99b4d704603c1559dfb72f542c2&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2022-01-11 11:47:42 +0530'>2022-01-11</span></td><td><a href='/guix/commit/gnu/services/ci.scm?id=c1f8dffa549edc0873c8b6956d9b288b51bea521'>services: laminar: Set LAMINAR_BIND_RPC environment variable.</a><span class='msg-avail'>...<span class='msg-tooltip'>Earlier, the bind-rpc field of &lt;laminar-configuration&gt; was not used at
all. This was a bug.

* gnu/services/ci.scm (laminar-shepherd-service): Use bind-rpc to set
LAMINAR_BIND_RPC environment variable.
</span></span></td><td>Arun Isaac</td></tr>
<tr><td><span title='2021-06-10 09:58:20 +0530'>2021-06-10</span></td><td><a href='/guix/commit/gnu/services/ci.scm?id=0d2cbd663214a8aa4ed8b8c7716fe3436801a9a5'>services: laminar: Create parent directory for unix socket.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/ci.scm (laminar-activation): New function.
(laminar-service-type): Extend activation-service-type with
laminar-activation.
</span></span></td><td>Arun Isaac</td></tr>
<tr><td><span title='2021-04-09 11:59:58 +0100'>2021-04-09</span></td><td><a href='/guix/commit/gnu/services/ci.scm?id=eda4bb4f16f74436b0caf1c584888c89b3c4c69b'>services: Add Laminar.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/services/ci.scm: New file.
* gnu/tests/ci.scm: New file.
* doc/guix.texi (Laminar): Document the Laminar service.
</span></span></td><td>Christopher Baines</td></tr>