Re: [Bug #13463] Poor SSD performance

[Wu Fengguang <fengguang.wu@intel.com>]

> Bug-Entry	: http://bugzilla.kernel.org/show_bug.cgi?id=13463
> Subject		: Poor SSD performance
> Submitter	: Jake <ellowitz@uchicago.edu>
> 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