FWIW: I (@rondy) am not the creator of the content shared here, which is an excerpt from Edmond Lau's book. I simply copied and pasted it from another location and saved it as a personal note, before it gained popularity on news.ycombinator.com. Unfortunately, I cannot recall the exact origin of the original source, nor was I able to find the author's name, so I am can't provide the appropriate credits.
| #file proxysql.cfg | |
| # This config file is parsed using libconfig , and its grammar is described in: | |
| # http://www.hyperrealm.com/libconfig/libconfig_manual.html#Configuration-File-Grammar | |
| # Grammar is also copied at the end of this file | |
| datadir="/var/lib/proxysql" |
| # Hello, and welcome to makefile basics. | |
| # | |
| # You will learn why `make` is so great, and why, despite its "weird" syntax, | |
| # it is actually a highly expressive, efficient, and powerful way to build | |
| # programs. | |
| # | |
| # Once you're done here, go to | |
| # http://www.gnu.org/software/make/manual/make.html | |
| # to learn SOOOO much more. |
| // Copyright (c) 2017 Ismael Celis | |
| // Permission is hereby granted, free of charge, to any person obtaining a copy | |
| // of this software and associated documentation files (the "Software"), to deal | |
| // in the Software without restriction, including without limitation the rights | |
| // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
| // copies of the Software, and to permit persons to whom the Software is | |
| // furnished to do so, subject to the following conditions: | |
| // The above copyright notice and this permission notice shall be included in all |
| 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 |
