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@jboner
jboner / latency.txt
Last active November 19, 2024 14:58
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
@return1
return1 / trim_enabler.txt
Last active May 26, 2024 11:01
TRIM Enabler for OS X Yosemite 10.10.3
#
# UPDATE for 10.10.4+: please consider this patch obsolete, as apple provides a tool called "trimforce" to enable trim support for 3rd party SSDs
# just run "sudo trimforce enable" to activate the trim support from now on!
#
# Original version by Grant Parnell is offline (http://digitaldj.net/2011/07/21/trim-enabler-for-lion/)
# Update July 2014: no longer offline, see https://digitaldj.net/blog/2011/11/17/trim-enabler-for-os-x-lion-mountain-lion-mavericks/
#
# Looks for "Apple" string in HD kext, changes it to a wildcard match for anything
#
# Alternative to http://www.groths.org/trim-enabler-3-0-released/
@vincentbernat
vincentbernat / gist:4391597
Created December 27, 2012 20:19
`socat` as an SSH reverse proxy (or anything TCP-based)
local$ socat TCP-LISTEN:2222,bind=127.0.0.1,reuseaddr,fork TCP-LISTEN:2223,reuseaddr
local$ ssh -p 2222 -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no localhost
remote$ socat TCP:10.0.2.2:2223 TCP:127.0.0.1:22