diff options
| -rw-r--r-- | doc/guix.texi | 30 | ||||
| -rw-r--r-- | guix/scripts/offload.scm | 54 |
2 files changed, 62 insertions, 22 deletions
diff --git a/doc/guix.texi b/doc/guix.texi index 3fc76c8670..553a3b8ae9 100644 --- a/doc/guix.texi +++ b/doc/guix.texi @@ -1081,7 +1081,28 @@ architecture natively supports it, via emulation (@pxref{Transparent Emulation with QEMU}), or both. Missing prerequisites for the build are copied over SSH to the target machine, which then proceeds with the build; upon success the output(s) of the build are copied back to the -initial machine. +initial machine. The offload facility comes with a basic scheduler that +attempts to select the best machine. The best machine is chosen among +the available machines based on criteria such as: + +@enumerate +@item +The availability of a build slot. A build machine can have as many +build slots (connections) as the value of the @code{parallel-builds} +field of its @code{build-machine} object. + +@item +Its relative speed, as defined via the @code{speed} field of its +@code{build-machine} object. + +@item +Its load. The normalized machine load must be lower than a threshold +value, configurable via the @code{overload-threshold} field of its +@code{build-machine} object. + +@item +Disk space availability. More than a 100 MiB must be available. +@end enumerate The @file{/etc/guix/machines.scm} file typically looks like this: @@ -1185,6 +1206,13 @@ when transferring files to and from build machines. File name of the Unix-domain socket @command{guix-daemon} is listening to on that machine. +@item @code{overload-threshold} (default: @code{0.6}) +The load threshold above which a potential offload machine is +disregarded by the offload scheduler. The value roughly translates to +the total processor usage of the build machine, ranging from 0.0 (0%) to +1.0 (100%). It can also be disabled by setting +@code{overload-threshold} to @code{#f}. + @item @code{parallel-builds} (default: @code{1}) The number of builds that may run in parallel on the machine. diff --git a/guix/scripts/offload.scm b/guix/scripts/offload.scm index 3dc8ccefcb..a5fe98b675 100644 --- a/guix/scripts/offload.scm +++ b/guix/scripts/offload.scm @@ -88,6 +88,10 @@ (default 3)) (daemon-socket build-machine-daemon-socket ; string (default "/var/guix/daemon-socket/socket")) + ;; A #f value tells the offload scheduler to disregard the load of the build + ;; machine when selecting the best offload machine. + (overload-threshold build-machine-overload-threshold ; inexact real between + (default 0.6)) ; 0.0 and 1.0 | #f (parallel-builds build-machine-parallel-builds ; number (default 1)) (speed build-machine-speed ; inexact real @@ -391,30 +395,34 @@ of free disk space on '~a'~%") (* 100 (expt 2 20))) ;100 MiB (define (node-load node) - "Return the load on NODE. Return +∞ if NODE is misbehaving." + "Return the load on NODE, a normalized value between 0.0 and 1.0. The value +is derived from /proc/loadavg and normalized according to the number of +logical cores available, to give a rough estimation of CPU usage. Return +1.0 (fully loaded) if NODE is misbehaving." (let ((line (inferior-eval '(begin (use-modules (ice-9 rdelim)) (call-with-input-file "/proc/loadavg" read-string)) - node))) - (if (eof-object? line) - +inf.0 ;MACHINE does not respond, so assume it is infinitely loaded + node)) + (ncores (inferior-eval '(begin + (use-modules (ice-9 threads)) + (current-processor-count)) + node))) + (if (or (eof-object? line) (eof-object? ncores)) + 1.0 ;MACHINE does not respond, so assume it is fully loaded (match (string-tokenize line) ((one five fifteen . x) - (string->number one)) + (let ((load (/ (string->number one) ncores))) + (if (> load 1.0) + 1.0 + load))) (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) load normalized) - normalized) - load)) + 1.0))))) + +(define (report-load machine load) + (format (current-error-port) + "normalized load on machine '~a' is ~,2f~%" + (build-machine-name machine) load)) (define (random-seed) (logxor (getpid) (car (gettimeofday)))) @@ -472,11 +480,15 @@ slot (which must later be released with 'release-build-slot'), or #f and #f." (let* ((session (false-if-exception (open-ssh-session best %short-timeout))) (node (and session (remote-inferior session))) - (load (and node (normalized-load best (node-load node)))) + (load (and node (node-load node))) + (threshold (build-machine-overload-threshold best)) (space (and node (node-free-disk-space node)))) + (when load (report-load best load)) (when node (close-inferior node)) (when session (disconnect! session)) - (if (and node (< load 2.) (>= space %minimum-disk-space)) + (if (and node + (or (not threshold) (< load threshold)) + (>= space %minimum-disk-space)) (match others (((machines slots) ...) ;; Release slots from the uninteresting machines. @@ -708,13 +720,13 @@ machine." (free (node-free-disk-space inferior))) (close-inferior inferior) (format #t "~a~% kernel: ~a ~a~% architecture: ~a~%\ - host name: ~a~% normalized load: ~a~% free disk space: ~,2f MiB~%\ + host name: ~a~% normalized load: ~,2f~% free disk space: ~,2f MiB~%\ time difference: ~a s~%" (build-machine-name machine) (utsname:sysname uts) (utsname:release uts) (utsname:machine uts) (utsname:nodename uts) - (normalized-load machine load) + load (/ free (expt 2 20) 1.) (- time now)))))))) |