Just for completeness... I should also mention that... The 32 core system has the AVX2 extension. I've tried this on a 12 Core system without the AVX2 extension. In that case, it's using SSE24 to do the xor. I get pretty much the same results on either system. Bob Kierski Senior Storage Performance Engineer Cray Inc. 380 Jackson Street Suite 210 St. Paul, MN 55101 Tele: 651-967-9590 Fax: 651-605-9001 Cell: 651-890-7461 -----Original Message----- From: Phil Turmel [mailto:philip@xxxxxxxxxx] Sent: Wednesday, December 02, 2015 8:45 AM To: Robert Kierski; Dallas Clement Cc: linux-raid@xxxxxxxxxxxxxxx Subject: Re: RAID 5,6 sequential writing seems slower in newer kernels On 12/02/2015 09:18 AM, Robert Kierski wrote: > Sorry... I should have mentioned that I'm running the 3.18.4 kernel > with a 32 core xeon and 128G of memory. I'm not using a FS, I'm going > directly to the raid block device. I'm not sure if the parallelization of raid parity has been merged yet, but I'm pretty sure it isn't in 3.18. With one core tied up computing parity and the rest idle, that'd be 96.875% idle. Phil ��.n��������+%������w��{.n�����{����w��ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
