Set the names of more threads

To help with debugging.

guix-data-service/poll-git-repository.scm

@@ -25,6 +25,8 @@
   #:use-module (git)
   #:use-module (guix git)
   #:use-module (guix channels)
+  #:use-module ((guix build syscalls)
+                #:select (set-thread-name))
   #:use-module (guix-data-service database)
   #:use-module (guix-data-service model git-repository)
   #:use-module (guix-data-service model git-branch)
@@ -35,6 +37,13 @@
 (define (start-thread-to-poll-git-repository git-repository-id)
   (call-with-new-thread
    (lambda ()
+     (catch 'system-error
+       (lambda ()
+         (set-thread-name
+          (simple-format #f "poll git ~A"
+                         git-repository-id)))
+       (const #t))
+
      (libgit2-init!)
      (honor-system-x509-certificates!)
 

guix-data-service/web/server.scm

@@ -26,7 +26,10 @@
   #:use-module (system repl error-handling)
   #:use-module (ice-9 atomic)
   #:use-module (fibers)
+  #:use-module (fibers scheduler)
   #:use-module (fibers conditions)
+  #:use-module ((guix build syscalls)
+                #:select (set-thread-name))
   #:use-module (prometheus)
   #:use-module (guix-data-service utils)
   #:use-module (guix-data-service database)
@@ -75,6 +78,22 @@
      (lambda ()
        (run-fibers
         (lambda ()
+          (let* ((current (current-scheduler))
+                 (schedulers
+                  (cons current (scheduler-remote-peers current))))
+            (for-each
+             (lambda (i sched)
+               (spawn-fiber
+                (lambda ()
+                  (catch 'system-error
+                    (lambda ()
+                      (set-thread-name
+                       (string-append "fibers " (number->string i))))
+                    (const #t)))
+                sched))
+             (iota (length schedulers))
+             schedulers))
+
           (parameterize
               ((connection-pool
                 (make-resource-pool