Re: [PATCH 1/1] blk-mq: map all HWQ also in hyperthreaded system
From: Guilherme G. Piccoli <hidden>
Date: 2017-06-28 14:44:09
Also in:
linux-nvme
On 06/28/2017 09:44 AM, Max Gurtovoy wrote:
This patch performs sequential mapping between CPUs and queues. In case the system has more CPUs than HWQs then there are still CPUs to map to HWQs. In hyperthreaded system, map the unmapped CPUs and their siblings to the same HWQ. This actually fixes a bug that found unmapped HWQs in a system with 2 sockets, 18 cores per socket, 2 threads per core (total 72 CPUs) running NVMEoF (opens upto maximum of 64 HWQs). Performance results running fio (72 jobs, 128 iodepth) using null_blk (w/w.o patch): bs IOPS(read submit_queues=72) IOPS(write submit_queues=72) IOPS(read submit_queues=24) IOPS(write submit_queues=24) ----- ---------------------------- ------------------------------ ---------------------------- ----------------------------- 512 4890.4K/4723.5K 4524.7K/4324.2K 4280.2K/4264.3K 3902.4K/3909.5K 1k 4910.1K/4715.2K 4535.8K/4309.6K 4296.7K/4269.1K 3906.8K/3914.9K 2k 4906.3K/4739.7K 4526.7K/4330.6K 4301.1K/4262.4K 3890.8K/3900.1K 4k 4918.6K/4730.7K 4556.1K/4343.6K 4297.6K/4264.5K 3886.9K/3893.9K 8k 4906.4K/4748.9K 4550.9K/4346.7K 4283.2K/4268.8K 3863.4K/3858.2K 16k 4903.8K/4782.6K 4501.5K/4233.9K 4292.3K/4282.3K 3773.1K/3773.5K 32k 4885.8K/4782.4K 4365.9K/4184.2K 4307.5K/4289.4K 3780.3K/3687.3K 64k 4822.5K/4762.7K 2752.8K/2675.1K 4308.8K/4312.3K 2651.5K/2655.7K 128k 2388.5K/2313.8K 1391.9K/1375.7K 2142.8K/2152.2K 1395.5K/1374.2K
Max, thanks for this patch. I was having the same issue, and was thinking in how to address... Your patch fixes it for me, just tested it. I can test any follow-up patch you send, basaed on reviews you got in the list. Cheers, Guilherme