workermonkey

PCI.

On my load balancers it is more like 5-10%. Not terrible, but not trivial either. Also, it multiplies throughout the environment. If you are dealing with PII or financials, everything needs to be encrypted on the wire.

Load balancer decrypts, looks at headers, decides what to do, re-encrypts, down to the app tier, decrypt, respond encrypted, etc. I'm not saying that is a bad thing, but that's why some people get cranky.

Somewhat unrelated, compressed headers in HTTP 2.0 makes sense if you only think about the browser, it saves 'repeated' information. The problem is the LB has to decrypt them every time anyways, so someone still have to do the work, it just isn't on the wire. Server push on the other hand could be awesome for performance (pre-cache the resources for the next page in a flow) but also has the potential for abuse.

The do not 'provide liquidity' -- the liquidity is already there. Suppose there is a stock selling at $100. You want to buy 100,000 shares, and there are people willing to sell. A HFT leaves some bait 100 share blocks for sale at that price. You buy those first, they use the advantage of speed to buy any other $100 shares available. They then sell you what you wanted to buy at $100.10.

What value did they add to the market? Bringing buyers and sellers together? Nope. Provide capital to the market? (Which is why stocks supposedly exist...) Nope. They end every day owning nothing.

Lewis's book also shows that many banks and brokers instead route some trades through their own internal 'markets' first, trying to find a match, instead of just trying to get the fairest price available.

Everyone gets screwed. There was a HFT trader who boasted that they went years without ever having a losing day. The only way to do that is in a market that isn't fair, where not all parties have equal access to information.