# Multithread raid5: Is check-for-completions also multithreaded (using async\_xor) ?

- From: Aggarwal, Vikas \<hidden\>
- Date: 2016-06-09 10:55:51 
- List: linux-raid
- Page: https://ratatoskr.run/linux-raid/2016/06/6632231
- Thread: https://ratatoskr.run/linux-raid/2016/06/6632231/t.md

```text
Hello All,
With multithread raid5 enabled (echo 48 > /sys/block/md51/md/group_thread_cnt)  what I understand is that all the cpu cores will be able to submit   async_xor  instructions in parallel for a single md raid5  device.

Question: About polling for completion, is that also multi-threaded ? - Does the same number of worker threads (48 in my test) will continue poll for XOR completion as well ? 
My multi-core SoC  has  XOR/GF offload channel, and I am trying to see how to get the best throughput for raid5 rebuild using multithread functionality.

Regards
Vikas Aggarwal
```