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[Qemu-devel] [PATCH v4 0/3] pc: mmap kernel (ELF image) and initrd
From: |
Stefano Garzarella |
Subject: |
[Qemu-devel] [PATCH v4 0/3] pc: mmap kernel (ELF image) and initrd |
Date: |
Wed, 24 Jul 2019 16:31:02 +0200 |
In order to reduce the memory footprint when PVH kernel and initrd
are used, we map them into memory instead of reading them.
In this way we can share them between multiple instances of QEMU.
v4:
- Patch 1: fix the rom_add_elf_program() comment [Paolo]
- Patch 2:
~ fix the missing of g_mapped_file_unref() in the success case [Paolo]
~ fix the rom_add_elf_program() comment [Paolo]
v3: https://patchew.org/QEMU/address@hidden/
v2: https://patchew.org/QEMU/address@hidden/
These are the results using a PVH kernel and initrd (cpio):
- memory footprint (using smem) [MB]
QEMU before now
# instances USS PSS USS PSS
1 102.0M 105.8M 102.3M 106.2M
2 94.6M 101.2M 72.3M 90.1M
4 94.1M 98.0M 72.0M 81.5M
8 94.0M 96.2M 71.8M 76.9M
16 93.9M 95.1M 71.6M 74.3M
Initrd size: 3.0M
Kernel
image size: 28M
sections size [size -A -d vmlinux]: 18.9M
- boot time [ms]
before now
qemu_init_end: 63.85 55.91
linux_start_kernel: 82.11 (+18.26) 74.51 (+18.60)
linux_start_user: 169.94 (+87.83) 159.06 (+84.56)
QEMU command used:
./qemu-system-x86_64 -bios /path/to/seabios/out/bios.bin -no-hpet \
-machine q35,accel=kvm,kernel_irqchip,nvdimm,sata=off,smbus=off,vmport=off \
-cpu host -m 1G -smp 1 -vga none -display none -no-user-config -nodefaults \
-kernel /path/to/vmlinux -initrd /path/to/rootfs.cpio \
-append 'root=/dev/mem0 ro console=hvc0 pci=lastbus=0 nosmap'
Stefano Garzarella (3):
loader: Handle memory-mapped ELFs
elf-ops.h: Map into memory the ELF to load
hw/i386/pc: Map into memory the initrd
hw/core/loader.c | 38 +++++++++++++++++++-----
hw/i386/pc.c | 17 ++++++++---
include/hw/elf_ops.h | 71 ++++++++++++++++++++++++++------------------
include/hw/i386/pc.h | 1 +
include/hw/loader.h | 5 ++--
5 files changed, 89 insertions(+), 43 deletions(-)
--
2.20.1
- [Qemu-devel] [PATCH v4 0/3] pc: mmap kernel (ELF image) and initrd,
Stefano Garzarella <=
- [Qemu-devel] [PATCH v4 1/3] loader: Handle memory-mapped ELFs, Stefano Garzarella, 2019/07/24
- [Qemu-devel] [PATCH v4 2/3] elf-ops.h: Map into memory the ELF to load, Stefano Garzarella, 2019/07/24
- [Qemu-devel] [PATCH v4 3/3] hw/i386/pc: Map into memory the initrd, Stefano Garzarella, 2019/07/24
- Re: [Qemu-devel] [PATCH v4 0/3] pc: mmap kernel (ELF image) and initrd, Paolo Bonzini, 2019/07/24
- Re: [Qemu-devel] [PATCH v4 0/3] pc: mmap kernel (ELF image) and initrd, Dr. David Alan Gilbert, 2019/07/24
- Re: [Qemu-devel] [PATCH v4 0/3] pc: mmap kernel (ELF image) and initrd, Montes, Julio, 2019/07/24