Redis latency spikes and the Linux kernel: a few more details
Unfortunately I just spotted that I'm totally wrong, the huge pages apparently are only used by jemalloc: I just mis-read the outputs since this seemed so obvious. So on the contrary, it appears that the high latency is due to the huge pages thing for some unknown reason. So actually it is malloc that, while NOT using huge pages, is going much faster. I've no idea about what is happening here, so please disregard the blog posts conclusions (all the rest is hopefully correct).<p>EDIT: Oh wait... since the problem is huge pages, this is MUCH better, since we can disable it. And I just verified that it works:<p>echo never > /sys/kernel/mm/transparent_hugepage/enabled<p>This means, free latency upgrade for all the Redis users out there during fork... (more or less 20x in my tests) just with this line above.