Hi Leo! Leo Famulari <l...@famulari.name> writes:
> On Tue, Apr 06, 2021 at 05:42:15PM -0400, Maxim Cournoyer wrote: >> From c720e68229322e5c38c0321b021e8d6430636111 Mon Sep 17 00:00:00 2001 >> From: Maxim Cournoyer <maxim.courno...@gmail.com> >> Date: Tue, 6 Apr 2021 17:37:33 -0400 >> Subject: [PATCH] system: vm: Set a larger value for the msize option of the >> 9p >> file system. >> >> Fixes <https://issues.guix.gnu.org/47225>. >> >> * gnu/system/vm.scm (mapping->file-system): Set the msize option to a value >> of >> 100 MiB (from the default 8 KiB). >> >> Reported-by: Leo Famulari <l...@famulari.name> > > Thanks! I'll test and push along with the next kernel update (that's > when I noticed this warning). Feel free to push sooner if you like. I hope I'm timely; I've made a revised version of the patch, that should cover more cases (and actually uses 100 MiB rather than 1 MiB :-)). Thank you,
From eb600c4ffbc8016709db9471f9dc0be1d60167a7 Mon Sep 17 00:00:00 2001 From: Maxim Cournoyer <maxim.courno...@gmail.com> Date: Tue, 6 Apr 2021 17:37:33 -0400 Subject: [PATCH] system: vm: Set a larger value for the msize option of the 9p file system. Fixes <https://issues.guix.gnu.org/47225>. * gnu/system/vm.scm (%default-msize-value): New variable. (%linux-vm-file-systems): Use it as the value of the msize option. (mapping->file-system): Likewise. Reported-by: Leo Famulari <l...@famulari.name> --- gnu/system/vm.scm | 18 ++++++++++++++---- 1 file 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))))) -- 2.31.1
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