Re: copy speed slows down after kernel update

Re: copy speed slows down after kernel update

[Tejun Heo]

Hello,

On Fri, Nov 28, 2014 at 02:13:35PM +0400, Михаил wrote:
> Technical description:
> MacBook Air Model A1370 (googling as: Apple MacBook Air "Core i7" 1.8 11"
> (Mid-2011))
> Disk A: Lacie Little Big Disk with Samsung HN-M101MBB 1 TB
> Disk B: Lacie Little Big Disk with OCZ Vertex 3
> Disk C: Seagate thunderbolt Adapter from STCB3000400 with OCZ Vertex 3
> Disk D: Seagate thunderbolt Adapter from STCB3000400 with Samsung
> HN-M101MBB 1 TB
> 
> using copy cammand: dd if=/dev/sda(internal Mac Book disk)
> of=/mnt/sdb1/test.dd bs=4M
> 
> Test bench 1. Bootable distro based on Debian whezzy 7.2 stable from
> October 12, 2013, kernel 3.2.0.4
> 1.1 Disk A (ext2). Stable copying speed = 81,4 MB/s.
> 1.2 Disk B (ext2). Stable copying speed = 196 MB/s. !!!!!
> 1.3 Disk C (ext2). Stable copying speed = 199 MB/s.
> 1.4 Disk D (ext2). Stable copying speed = 87 MB/s.
> 
> Test bench 2. Bootable distro based on Debian jessie from November 17,
> 2014, kernel 3.16.7 + thunderbolt driver compiled in.
> 2.1 Disk A (ext2). Stable copying speed = 94 MB/s.
> 2.2 Disk B (ext2). Stable copying speed = 150 MB/s. !!!!!!
> 
> Test bench 3. Bootable distro based on Debian jessie from November 17,
> 2014, kernel 3.17.3 + thunderbolt driver compiled as module.
> 3.1 Disk A (ext2). Stable copying speed = 97 MB/s.
> 3.2 Disk B (ext2). Stable copying speed = 151 MB/s.
> 3.3 Disk C (ext2). Stable copying speed = 156 MB/s. !!!!!
> 3.4 Disk D (ext2). Stable copying speed = 108 MB/s.
> 
> after and before insmod .../thunderbolt.ko the same results.

Can you please post kernel boot messages from the old and new kernels?

Thanks.

-- 
tejun