Adding YCSB timestamping for tectonic

Adding YCSB timestamping for tectonic

[kirill.sc, 2016-12-09 11:12:07]

Hi Lorenzo, 

See my implementation of YCSB timestamping in kernel. Please understand the code
and review it.

[lorenzo.corneo, 2016-12-12 08:40:31]

Here my review.

https://codereview.appspot.com/312170043/diff/1/kernel_mods/kfilter.c
File kernel_mods/kfilter.c (right):

https://codereview.appspot.com/312170043/diff/1/kernel_mods/kfilter.c#newcode101
kernel_mods/kfilter.c:101: #define INPACK_YCSB_REQUEST 5   /* YCSB incoming
request */
If you are referring to fifth byte of the payload, this should be 7.

https://codereview.appspot.com/312170043/diff/1/kernel_mods/kfilter.c#newcode102
kernel_mods/kfilter.c:102: #define OUTPACK_YCSB_RESPONSE 6 /* Reply to YCSB */
If you are referring to fifth byte of the payload, this should be 8.

https://codereview.appspot.com/312170043/diff/1/kernel_mods/ktracer.h
File kernel_mods/ktracer.h (right):

https://codereview.appspot.com/312170043/diff/1/kernel_mods/ktracer.h#newcode92
kernel_mods/ktracer.h:92: uint8_t rqst_resp_type;
Isn't it better if we have uint16_t for the request_type and we get rid of
unused?

https://codereview.appspot.com/312170043/diff/1/kernel_mods/ktracer.h#newcode97
kernel_mods/ktracer.h:97: uint16_t rqst_id;
In order too keep consistency between YCSB and this structure, I suggest to
rename this field to stream_id.

https://codereview.appspot.com/312170043/diff/1/kernel_mods/ktracer.h#newcode104
kernel_mods/ktracer.h:104: #define YCSB_REQUEST_TYPE 4
From wireshark I see that request type is 3

https://codereview.appspot.com/312170043/diff/1/kernel_mods/ktracer.h#newcode105
kernel_mods/ktracer.h:105: #define YCSB_RESPONSE_TYPE 132
From Wireshark I see that response type is 131 (0x83)