bz31 bz31

bz31 / gist:c1d1f2941eb5f6b0eeac8ef7ec78a281

Last active February 24, 2024 03:46 — forked from hacksalot/gist:72517b9b1c145116e89e

Delete GitHub wiki revisions

	# Delete prior revisions from a GitHub wiki so that only the most-recent
	# version of the content is available.

	# Clone the wiki.
	git clone https://github.com/[user]/[repo].wiki.git
	# Example: git clone https://github.com/bz31/Buildroot.wiki.git

	# Remove the .git folder.
	cd [repo].wiki
	rm -rf .git

bz31 / latency.txt

Created December 18, 2018 19:42 — forked from jboner/latency.txt

Latency Numbers Every Programmer Should Know

	Latency Comparison Numbers (~2012)
	----------------------------------
	L1 cache reference 0.5 ns
	Branch mispredict 5 ns
	L2 cache reference 7 ns 14x L1 cache
	Mutex lock/unlock 25 ns
	Main memory reference 100 ns 20x L2 cache, 200x L1 cache
	Compress 1K bytes with Zippy 3,000 ns 3 us
	Send 1K bytes over 1 Gbps network 10,000 ns 10 us
	Read 4K randomly from SSD* 150,000 ns 150 us ~1GB/sec SSD

bz31 / gist:073adedc362b361d0317d7ef64b3c305

Last active November 7, 2019 16:14 — forked from naodesu/gist:10620506

How to mount ubifs image in Linux Debian Stretch.

	# Install mtd-utils

	# $UBIFS is a ubifs image file
	# make sure $UBIFS is a ubifs image file
	blkid $(UBIFS)
	$(UBIFS): ... TYPE="ubifs"

	# size of created mtd is 256.0 MiB
	/usr/sbin/modprobe nandsim first_id_byte=0x2c second_id_byte=0xda third_id_byte=0x90 fourth_id_byte=0x95
	/usr/sbin/flash_erase /dev/mtd0 0 0