Re: [PATCH v2 03/10] ArmVirtPkg: raise PcdShellFileOperationSize to 128KB

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 1/13/21 9:54 AM, Laszlo Ersek wrote:
> Some UEFI shell commands read and write files in chunks. The chunk size is
> given by "PcdShellFileOperationSize", whose default in
> "ShellPkg/ShellPkg.dec" is 4KB (0x1000).
> 
> The virtio-fs daemon of QEMU advertizes a 128KB maximum buffer size by
> default, for the FUSE_WRITE operation.
> 
> By raising PcdShellFileOperationSize 32-fold, the number of FUSE write
> requests shrinks proportionately, when writing large files. And when a
> Virtio Filesystem is not used, a 128KB chunk size is still not
> particularly wasteful.
> 
> Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
> Cc: Leif Lindholm <leif@nuviainc.com>
> Cc: Philippe Mathieu-Daudé <philmd@redhat.com>
> Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3125
> Signed-off-by: Laszlo Ersek <lersek@redhat.com>
> Acked-by: Ard Biesheuvel <ard.biesheuvel@arm.com>
> ---
> 
> Notes:
>     v2:
>     - no changes
>     - pick up Ard's A-b
> 
>  ArmVirtPkg/ArmVirtQemu.dsc       | 1 +
>  ArmVirtPkg/ArmVirtQemuKernel.dsc | 1 +
>  2 files changed, 2 insertions(+)

(Similar comment that OVMF patch, QEMU should advertise properly the
maximum buffer size).

Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>