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authorLudovic Courtès <ludo@gnu.org>2018-12-21 22:54:02 +0100
committerLudovic Courtès <ludo@gnu.org>2018-12-21 23:50:13 +0100
commitbbe66a530a014e8146d63002a5294941e935f863 (patch)
tree5b7e97cefa1717136d4c4d4794f9f7e9e72743b5
parent295430f0cfdff1ca517cfa74136b550fecf6efcb (diff)
downloadguix-bbe66a530a014e8146d63002a5294941e935f863.tar
guix-bbe66a530a014e8146d63002a5294941e935f863.tar.gz
offload: Decompose 'machine-load' into simpler procedures.
* guix/scripts/offload.scm (machine-load): Remove. (node-load, normalized-load): New procedures. (choose-build-machine): Call 'open-ssh-session' and 'make-node' from here; pass the node to 'node-load'. (check-machine-status): Use 'node-load' instead of 'machine-load'. Call 'disconnect!' on SESSION.
-rw-r--r--guix/scripts/offload.scm92
1 files changed, 48 insertions, 44 deletions
diff --git a/guix/scripts/offload.scm b/guix/scripts/offload.scm
index ee5857e16b..c345d438d1 100644
--- a/guix/scripts/offload.scm
+++ b/guix/scripts/offload.scm
@@ -392,33 +392,31 @@ MACHINE."
(build-requirements-features requirements)
(build-machine-features machine))))
-(define (machine-load machine)
- "Return the load of MACHINE, divided by the number of parallel builds
-allowed on MACHINE. Return +∞ if MACHINE is unreachable."
- ;; Note: This procedure is costly since it creates a new SSH session.
- (match (false-if-exception (open-ssh-session machine))
- ((? session? session)
- (let* ((pipe (open-remote-pipe* session OPEN_READ
- "cat" "/proc/loadavg"))
- (line (read-line pipe)))
- (close-port pipe)
- (disconnect! session)
-
- (if (eof-object? line)
- +inf.0 ;MACHINE does not respond, so assume it is infinitely loaded
- (match (string-tokenize line)
- ((one five fifteen . x)
- (let* ((raw (string->number one))
- (jobs (build-machine-parallel-builds machine))
- (normalized (/ raw jobs)))
- (format (current-error-port) "load on machine '~a' is ~s\
+(define (node-load node)
+ "Return the load on NODE. Return +∞ if NODE is misbehaving."
+ (let ((line (node-eval node
+ '(begin
+ (use-modules (ice-9 rdelim))
+ (call-with-input-file "/proc/loadavg"
+ read-string)))))
+ (if (eof-object? line)
+ +inf.0 ;MACHINE does not respond, so assume it is infinitely loaded
+ (match (string-tokenize line)
+ ((one five fifteen . x)
+ (string->number one))
+ (x
+ +inf.0)))))
+
+(define (normalized-load machine load)
+ "Divide LOAD by the number of parallel builds of MACHINE."
+ (if (rational? load)
+ (let* ((jobs (build-machine-parallel-builds machine))
+ (normalized (/ load jobs)))
+ (format (current-error-port) "load on machine '~a' is ~s\
(normalized: ~s)~%"
- (build-machine-name machine) raw normalized)
- normalized))
- (x
- +inf.0))))) ;something's fishy about MACHINE, so avoid it
- (x
- +inf.0))) ;failed to connect to MACHINE, so avoid it
+ (build-machine-name machine) load normalized)
+ normalized)
+ load))
(define (machine-lock-file machine hint)
"Return the name of MACHINE's lock file for HINT."
@@ -484,21 +482,25 @@ slot (which must later be released with 'release-build-slot'), or #f and #f."
(match machines+slots
(((best slot) others ...)
;; Return the best machine unless it's already overloaded.
- ;; Note: We call 'machine-load' only as a last resort because it is
+ ;; Note: We call 'node-load' only as a last resort because it is
;; too costly to call it once for every machine.
- (if (< (machine-load best) 2.)
- (match others
- (((machines slots) ...)
- ;; Release slots from the uninteresting machines.
- (for-each release-build-slot slots)
-
- ;; The caller must keep SLOT to protect it from GC and to
- ;; eventually release it.
- (values best slot)))
- (begin
- ;; BEST is overloaded, so try the next one.
- (release-build-slot slot)
- (loop others))))
+ (let* ((session (false-if-exception (open-ssh-session best)))
+ (node (and session (make-node session)))
+ (load (and node (normalized-load best (node-load node)))))
+ (when session (disconnect! session))
+ (if (and node (< load 2.))
+ (match others
+ (((machines slots) ...)
+ ;; Release slots from the uninteresting machines.
+ (for-each release-build-slot slots)
+
+ ;; The caller must keep SLOT to protect it from GC and to
+ ;; eventually release it.
+ (values best slot)))
+ (begin
+ ;; BEST is overloaded, so try the next one.
+ (release-build-slot slot)
+ (loop others)))))
(()
(values #f #f))))))
@@ -689,16 +691,18 @@ machine."
(info (G_ "getting status of ~a build machines defined in '~a'...~%")
(length machines) machine-file)
(for-each (lambda (machine)
- (let* ((node (make-node (open-ssh-session machine)))
- (uts (node-eval node '(uname))))
+ (let* ((session (open-ssh-session machine))
+ (node (make-node session))
+ (uts (node-eval node '(uname)))
+ (load (node-load node)))
+ (disconnect! session)
(format #t "~a~% kernel: ~a ~a~% architecture: ~a~%\
host name: ~a~% normalized load: ~a~%"
(build-machine-name machine)
(utsname:sysname uts) (utsname:release uts)
(utsname:machine uts)
(utsname:nodename uts)
- (parameterize ((current-error-port (%make-void-port "rw+")))
- (machine-load machine)))))
+ load)))
machines)))