84% of a single-threaded 1KB write in Redis is spent in the kernel
The concept of redis has always baffled me. A hash table is a very fast data structure. As soon as you put that in a dedicated server, the cost of the actual lookup is instantly eclipsed by the need to parse a text protocol and do network I/O to communicate with the client.So I'd be willing to say that the problem here isn't that the kernel stack is slow per-se, but that workload is too small as to make the overhead look ridiculous, when it'd be very much acceptable if your server did more actual work.