makedumpfile 1.5.4 + kernel 3.11-rc2+ 4TB tests

[Vivek Goyal]

On Fri, Jul 26, 2013 at 07:42:39PM +0800, Jingbai Ma wrote:
> Hi,
> 
> I have run some tests with makedumpfile 1.5.4 and upstream kernel
> 3.11-rc2+ on a machine with 4TB memory, here is testing results:
> 
> Test environment:
> Machine: HP ProLiant DL980 G7 with 4TB RAM.
> CPU: Intel(R) Xeon(R) CPU E7- 2860  @ 2.27GHz (8 sockets, 10 cores)
> (Only 1 CPU was enabled the 2nd kernel)
> Kernel: 3.11.0-rc2+ (at patch b3a3a9c441e2c8f6b6760de9331023a7906a4ac6)
> crashkernel=384MB
> vmcore size: 4.0TB
> Dump file size: 15GB
> All measured time from debug message of makedumpfile.
> As a comparison, I also have tested makedumpfile 1.5.3.
> 
> (all time in seconds)
>                      Excluding pages   Copy data   Total
> makedumpfile 1.5.3          468         1182       1650
> makedumpfile 1.5.4           93          518        611
> 
> 
> So it seems there is a great performance improvement by the mmap mechanism.

[CC Andrew].

Thanks Jingbai for testing results. Good to see that vmcore mmap() patches
are helping.

Thanks
Vivek