>A certain function (newSTDGen) was called repeatedly within each request It is called zero times in the json benchmark, which yesod still did quite poorly on.

>A certain function (newSTDGen) was called repeatedly within each request It is called zero times in the json benchmark, which yesod still did quite poorly on. That is only a factor in the "pull a random thing from the DB" test. I believe the biggest underlying issue was that sessions are enabled, which means transmitting more data (the cookie) as well as doing encryption and HMAC on the cookies. Disabling sessions doubled the performance.