[shepherd] 01/02: service: Reduce heap allocations while logging.

[Ludovic Courtès]

civodul pushed a commit to branch master
in repository shepherd.

commit 9bda2eb405460b48a34fdb54bd64b9770b482545
Author: Ludovic Courtès <ludo@gnu.org>
AuthorDate: Thu Oct 20 12:46:23 2022 +0200

    service: Reduce heap allocations while logging.
    
    * modules/shepherd/service.scm (%service-file-logger): Use 'display'
    and 'newline' instead of 'format' ('format' allocates a string port, etc.).
    (service-builtin-logger): Use 'simple-format'.
---
 modules/shepherd/service.scm | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/modules/shepherd/service.scm b/modules/shepherd/service.scm
index 08547de..9d0ade6 100644
--- a/modules/shepherd/service.scm
+++ b/modules/shepherd/service.scm
@@ -895,7 +895,10 @@ not exist."
               (line
                (let ((prefix (strftime default-logfile-date-format
                                        (localtime (current-time)))))
-                 (format output "~a~a~%" prefix line)
+                 ;; Avoid (ice-9 format) to reduce heap allocations.
+                 (display prefix output)
+                 (display line output)
+                 (newline output)
                  (loop))))))))))
 
 (define (service-file-logger file input)
@@ -925,8 +928,8 @@ FILE."
            ;; TODO: Print the PID of COMMAND.  The actual PID is potentially
            ;; not known until after 'read-pid-file' has completed, so it would
            ;; need to be communicated.
-           (format (log-output-port) "~a[~a] ~a~%"
-                   prefix command line))
+           (simple-format (log-output-port) "~a[~a] ~a~%"
+                          prefix command line))
          (loop))))))
 
 (define (format-supplementary-groups supplementary-groups)