diff options
| -rw-r--r-- | gnu/system/vm.scm | 18 |
1 files changed, 14 insertions, 4 deletions
diff --git a/gnu/system/vm.scm b/gnu/system/vm.scm index 3d0935b3af..1efae7ff06 100644 --- a/gnu/system/vm.scm +++ b/gnu/system/vm.scm @@ -88,6 +88,13 @@ ;;; ;;; Code: +;; By default, the msize value is 8 KiB, which according to QEMU is +;; insufficient and would degrade performance. The msize value should roughly +;; match the bandwidth of the system's IO (see: +;; https://wiki.qemu.org/Documentation/9psetup#msize). Use 100 MiB as a +;; conservative default. +(define %default-msize-value (* 100 (expt 2 20))) ;100 MiB + (define %linux-vm-file-systems ;; File systems mounted for 'derivation-in-linux-vm'. These are shared with ;; the host over 9p. @@ -103,21 +110,23 @@ (type "9p") (needed-for-boot? #t) (flags '(read-only)) - (options "trans=virtio,cache=loose") + (options (format #f "trans=virtio,cache=loose,msize=~a" + %default-msize-value)) (check? #f)) (file-system (mount-point "/xchg") (device "xchg") (type "9p") (needed-for-boot? #t) - (options "trans=virtio") + (options (format #f "trans=virtio,msize=~a" %default-msize-value)) (check? #f)) (file-system (mount-point "/tmp") (device "tmp") (type "9p") (needed-for-boot? #t) - (options "trans=virtio,cache=loose") + (options (format #f "trans=virtio,cache=loose,msize=~a" + %default-msize-value)) (check? #f)))) (define not-config? @@ -581,7 +590,8 @@ the operating system." (type "9p") (flags (if writable? '() '(read-only))) (options (string-append "trans=virtio" - (if writable? "" ",cache=loose"))) + (if writable? "" ",cache=loose") + ",msize=" (number->string %default-msize-value))) (check? #f) (create-mount-point? #t))))) |