On 10/7/20 3:54 PM, Mike Christie wrote: > This is a prep patch to support multiple vhost worker threads per vhost > dev. This patch converts the code that had assumed a single worker > thread by: > > 1. Moving worker related fields to a new struct vhost_worker. > 2. Converting vhost.c code to use the new struct and assume we will > have an array of workers. > 3. It also exports a helper function that will be used in the last > patch when vhost-scsi is converted to use this new functionality. > Oh yeah I also wanted to bring up this patch: https://www.spinics.net/lists/netdev/msg192548.html The problem with my multi-threading patches is that I was focused on the cgroup support parts and that lead to some gross decisions. 1. I kept the cgroup support, but as a result I do not have control over the threading affinity and making sure cmds are executed on a optimal CPU like the above patches do. When I drop the cgroup support and make sure threads are bound to specific CPUs and then make sure IO is run on the CPU it came in on then IOPs jumps from 600K to 800K for vhost-scsi. 2. I can possible create a lot of threads. So a couple open issues are: 1. Can we do a thread per cpu that is shared across all vhost devices? That would lead to dropping the cgroup vhost worker support. 2. Can we just use the kernel's workqueues then?
