a nicer README

1 files changed, 42 insertions, 18 deletions

diff --git a/README b/README
index ab8a381..3d6a5a4 100644
--- a/README
+++ b/README
@@ -1,26 +1,50 @@
-A simple x86 firmware that can boot Linux.  Usage:
+A simple x86 firmware that can boot Linux.
+
+Most of QEMU's 500-700 ms startup time is spent:
+
+* in the dynamic linker.  This can be reduced by 150 ms simply by
+  compiling a stripped down QEMU:
+
+    ./configure --disable-libssh2 --disable-tcmalloc --disable-glusterfs \
+        --disable-seccomp --disable-{bzip2,snappy,lzo} --disable-usb-redir \
+        --disable-libusb --disable-smartcard-nss --disable-libnfs  \
+        --disable-libiscsi --disable-rbd  --disable-spice --disable-attr \
+        --disable-cap-ng --disable-linux-aio --disable-uuid --disable-brlapi \
+        --disable-vnc-{jpeg,tls,sasl,png,ws} --disable-rdma --disable-bluez \
+        --disable-fdt --disable-curl --disable-curses --disable-sdl \
+        --disable-gtk  --disable-tpm --disable-vte --disable-vnc  \
+        --disable-xen --disable-opengl --target-list=x86_64-softmmu
+
+* in the BIOS.  qboot saves another 150 ms.
+
+* in fw_cfg.  This is fixed by putting kernel and initrd in a CoreBoot cbfs
+  image, and doing a memory copy from NVDIMM or flash instead of using fw_cfg.
+  Right now only flash is supported. 350 ms are saved, bringing the startup
+  time down to 60 ms.
+
+Usage
+=====
 
 fw_cfg based example:
 
-$ qemu-kvm -bios bios.bin \
-  -kernel /boot/vmlinuz-4.0.3-300.fc22.x86_64 \
-  -serial mon:stdio -append 'console=ttyS0,115200,8n1'
+    $ qemu-kvm -bios bios.bin \
+      -kernel /boot/vmlinuz-4.0.3-300.fc22.x86_64 \
+      -serial mon:stdio -append 'console=ttyS0,115200,8n1'
 
 cbfs-based example (pflash isn't the definitive interface though):
 
-$ dd if=/dev/zero of=boot.bin bs=4096 count=1
-$ cbfstool cbfs.rom create -s 8m -B boot.bin  -m x86 -o 0x1000
-$ cbfstool cbfs.rom add -f /boot/vmlinuz-4.0.3-300.fc22.x86_64 -n vmlinuz -t raw
-$ echo 'console=ttyS0,115200,8n1' > cmdline
-$ cbfstool cbfs.rom add -f cmdline -n cmdline -t raw
-$ qemu-kvm -drive if=pflash,file=bios.bin,readonly=on \
-    -drive if=pflash,file=cbfs.rom,readonly=on \
-    -serial mon:stdio
-
-TODO:
-- ACPI tables
-- SMBIOS tables
-- Multiboot loading
+    $ dd if=/dev/zero of=boot.bin bs=4096 count=1
+    $ cbfstool cbfs.rom create -s 8m -B boot.bin  -m x86 -o 0x1000
+    $ cbfstool cbfs.rom add -f /boot/vmlinuz-4.0.3-300.fc22.x86_64 -n vmlinuz -t raw
+    $ echo 'console=ttyS0,115200,8n1' > cmdline
+    $ cbfstool cbfs.rom add -f cmdline -n cmdline -t raw
+    $ qemu-kvm -drive if=pflash,file=bios.bin,readonly=on \
+        -drive if=pflash,file=cbfs.rom,readonly=on \
+        -serial mon:stdio
 
-Example:
+TODO
+====
 
+* ACPI tables
+* SMBIOS tables
+* Multiboot loading