why mic busspeedreadback and busspeeddownload is not steady?

[dl_h_]

~i have made a test about the BusSpeedReadback.

when the data is not small,it's performance is 6.xxGB/s.

Bus when the data reach to 1GB,the performance is not steady.

Sometimes it's 6.xxGB/s,sometimes 0.3xxGB/s.

Why the busspeedreadback,and busspeeddownload are not steady.

[dl_h_]

~when the data is  small!!!  an error

[Frances_R_Intel]

I don't know, off hand, what may be causing that. I have sent email to one of the people who worked on that code to see if they can provide an answer.

[MdRezaur_R_Intel]

I assume you are running the SHOC benchmark from https://github.com/vetter/shoc-mic. If so can you send me the output of the benchmark run, it should show you the statistical variation,

Regards

Reza

[MdRezaur_R_Intel]

BTW, I just ran the SHOC BusSpeedReadback with  1 GB of data transfer and seeing consistent result for 1 GB transfers 6.87 GB/s.

test	atts	units	median	mean	stddev	min	max	trial0	trial1	trial2	trial3	trial4	trial5	trial6	trial7	trial8	trial9
ReadbackSpeed	1048576kB	GB/sec	6.87285	6.87076	0.007744	6.85817	6.88146	6.87815	6.87696	6.87287	6.87142	6.87283	6.88146	6.87463	6.85817	6.86027	6.8608

[Andrey_Vladimirov]

dl. h.: go into BIOS and under "Advanced" set the parameter "Extended ATR" to 0x01. The symptoms you are seeing can occur when this parameter is set to its default value 0x03. See also http://software.intel.com/en-us/forums/topic/401509 for explanation.