gnu: Add ocaml-mirage-profile-unix.

* gnu/packages/ocaml.scm (ocaml-mirage-profile-unix): New variable.

Signed-off-by: Christopher Baines <mail@cbaines.net>

gnu/packages/ocaml.scm

@@ -3846,6 +3846,44 @@ (define-public ocaml-mirage-unix
 handles the main loop and timers.")
     (license license:isc)))
 
+(define-public ocaml-mirage-profile-unix
+  (package
+    (name "ocaml-mirage-profile-unix")
+    (version "0.9.1")
+    (source (origin
+              (method git-fetch)
+              (uri (git-reference
+                    (url "https://github.com/mirage/mirage-profile/")
+                    (commit (string-append "v" version))))
+              (file-name (git-file-name name version))
+              (sha256
+               (base32
+                "11p3ai8g993algds9mbg4xf3is0agqah127r69fb7rm35dryzq95"))))
+    (build-system dune-build-system)
+    (arguments
+     '(#:package "mirage-profile-unix"
+       #:tests? #f ;depends on ocaml-mirage-profile which would form a loop
+       #:phases (modify-phases %standard-phases
+                  ;; TODO is there a way to do this with dune build flags?
+                  (add-after 'unpack 'disable-xen
+                    (lambda _
+                      ;; this way it is not detected as a build target
+                      (rename-file "xen" "_xen"))))))
+    (propagated-inputs (list ocaml-cstruct ocaml-ocplib-endian ocaml-lwt
+                             ocaml-mtime ocaml-ppx-cstruct))
+    (native-inputs (list ocaml-ppx-cstruct))
+    (home-page "https://github.com/mirage/mirage-profile")
+    (synopsis "Collects Ocaml/Lwt profiling information in CTF format")
+    (description
+     "Used to trace execution of OCaml/Lwt programs (such as Mirage
+unikernels) at the level of Lwt threads.  The traces can be viewed using
+JavaScript or GTK viewers provided by mirage-trace-viewer or processed by
+tools supporting the Common Trace Format.
+When compiled against a normal version of Lwt, OCaml's cross-module inlining
+will optimise these calls away, meaning there should be no overhead in the
+non-profiling case.")
+    (license license:bsd-2)))
+
 (define-public ocaml-ocurl
   (package
     (name "ocaml-ocurl")