> > Hello, LSF. > > Title: Introduce a per-cpu-vmap-cache to eliminate a vmap lock contention > > Description: > Currently the vmap code is not scaled to number of CPU cores in a system > because a global vmap space is protected by a single spinlock. Such approach > has a clear bottleneck if many CPUs simultaneously access to one resource. > > In this talk i would like to describe a drawback, show some data related > to contentions and places where those occur in a code. Apart of that i > would like to share ideas how to eliminate it providing a few approaches > and compare them. > > Requirements: > * It should be a per-cpu approach; > * Search of freed ptrs should not interfere with other freeing(as much as we can); > * - offload allocated areas(buzy ones) per-cpu; > * Cache ready sized objects or merge them into one big per-cpu-space(split on demand); > * Lazily-freed areas either drained per-cpu individually or by one CPU for all; > * Prefetch a fixed size in front and allocate per-cpu > > Goals: > * Implement a per-cpu way of allocation to eliminate a contention. > Thank you for giving a time to talk about this topic on the LSFMMBPF. The slides can be accessed here: wget ftp://vps418301.ovh.net/incoming/Mitigate_a_vmalloc_lock_contention_in_SMP_env_v1.pdf There were some issues with a camera, but i was told in the end you could see me.2 Thank you again! -- Uladzislau Rezki
