Messages in this thread | | | Date | Tue, 16 Feb 2016 20:37:33 -0500 | From | Waiman Long <> | Subject | Re: [PATCH v2 1/3] lib/list_batch: A simple list insertion/deletion batching facility |
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On 02/06/2016 06:57 PM, Dave Chinner wrote: > On Wed, Feb 03, 2016 at 06:11:56PM -0500, Waiman Long wrote: >> On 01/31/2016 07:47 PM, Dave Chinner wrote: >>> So at what point does simply replacing the list_head with a list_lru >>> become more efficient than this batch processing (i.e. >>> https://lkml.org/lkml/2015/3/10/660)? The list_lru isn't a great >>> fit for the inode list (doesn't need any of the special LRU/memcg >>> stuff https://lkml.org/lkml/2015/3/16/261) but it will tell us if, >>> like Ingo suggested, moving more towards a generic per-cpu list >>> would provide better overall performance... >> I will take a look at the list_lru patch to see if that help. As for >> the per-cpu list, I tried that and it didn't quite work out. > OK, see my last email as to why Andi's patch didn't change anything. > The list_lru implementation has a list per node, a lock per node, > and each item is placed on the list for the node it is physically > allocated from. Hence for local workloads, the list/lock that is > accessed for add/remove should be local to the node and hence should > reduce cache line contention mostly to within a single node. > > Cheers, > > Dave.
I have just sent out a new patchset using per-cpu list with per-cpu locks. I used the per-cpu list as the changes will be simpler and easier to review. Please let me know your thought on that.
Thanks, Longman
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