Re: [Bug #13463] Poor SSD performance

Wu Fengguang
2009-06-10T06:37:46Z

> Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=13463
> Subject : Poor SSD performance
> Submitter : Jake <ellowitz-t4+EzPmVLfD2fBVCVOL8/A@public.gmane.org>
> Date : 2009-06-05 17:37 (3 days old)

Hi Jake,

Could you collect some blktrace data for the dd commands on new/old
kernels?

dd if=/dev/sda of=/dev/null bs=1M count=1024 iflag=direct
dd if=/dev/sda of=/dev/null bs=1M count=1024

You need to install the blktrace tool and run these commands:

cd /dev/shm
blktrace /dev/sda # do this while dd is running
# ^C to interrupt
blkparse sda

Package: blktrace
Description: utilities for block layer IO tracing
blktrace is a block layer IO tracing mechanism which provides detailed
information about request queue operations up to user space. There are

Thanks,
Fengguang