Re: [PATCH RESEND 1/3] initramfs: move unnecessary memcmp from hot path
From: Al Viro <viro@zeniv.linux.org.uk>
Date: 2021-08-04 12:59:32
Also in:
linux-fsdevel
On Wed, Aug 04, 2021 at 11:31:29AM +0200, David Disseldorp wrote:
Ping, any feedback on this change?
I think it's a no brainer, but for kicks I ran a few unrealistic micro
benchmarks on my laptop. Extraction time for a cpio image with 1M+
directories improved by 5ms (pre: 14.614s, post: 14.609s), when averaged
across 20 runs of:
qemu-system-x86_64 -machine accel=kvm -smp cpus=1 -m 10240 \
-kernel ~/linux/arch/x86/boot/bzImage \
-initrd ./initrds/gen_cpio.out \
-append "initramfs_async=0 console=ttyS0 panic=0" -nographic \
| awk '/Trying to unpack rootfs/ {start_ts = $2};
/Freeing initrd memory/ {end_ts = $2}
END {printf "%f\n", end_ts - start_ts}'What was the dispersion for those runs?