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author | Laszlo Ersek <lersek@redhat.com> | 2021-01-13 09:54:45 +0100 |
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committer | mergify[bot] <37929162+mergify[bot]@users.noreply.github.com> | 2021-01-19 18:23:28 +0000 |
commit | 2912341cd924ebc32889879912aa9588dae4d209 (patch) | |
tree | f8062bed2c2e785868123ad7d1d2ba14959c2fb2 /ArmVirtPkg/ArmVirtQemuKernel.dsc | |
parent | f72fd9616eedac9a521adcbbe5086dd666c67232 (diff) | |
download | edk2-2912341cd924ebc32889879912aa9588dae4d209.tar.gz edk2-2912341cd924ebc32889879912aa9588dae4d209.tar.bz2 edk2-2912341cd924ebc32889879912aa9588dae4d209.zip |
OvmfPkg: raise PcdShellFileOperationSize to 128KB
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.
Some ad-hoc measurements on my laptop, using OVMF:
- The time it takes to copy a ~270MB file from a Virtio Filesystem to the
same Virtio Filesystem improves from ~9 seconds to ~1 second.
- The time it takes to compare two identical ~270MB files on the same
Virtio Filesystem improves from ~11 seconds to ~3 seconds.
Cc: Ard Biesheuvel <ard.biesheuvel@arm.com>
Cc: Jordan Justen <jordan.l.justen@intel.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>
Message-Id: <20210113085453.10168-3-lersek@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Diffstat (limited to 'ArmVirtPkg/ArmVirtQemuKernel.dsc')
0 files changed, 0 insertions, 0 deletions