Address Trace Format

BYU Address Trace Format v1.1

A bug in the size field was corrected. It now shows lengths of 16 and 32 bytes (not just 8 and smaller). Length 8 still accounts for over 90% of the references.

BYU Address Trace Format v1.0

Each trace record contains twelve (12) bytes of information in the following format:

typedef struct BYUADDRESSTRACE
{
        unsigned long addr;
        unsigned char reqtype;
        unsigned char size;
        unsigned char attr;
        unsigned char proc;
        unsigned long time;
} p2AddrTr;

Address Field

The address field of the trace is a 32 bit physical address. This field is in little endian format and represents the address generated by the processor being traced.

Request Type Field

The request type field is one byte long. It describes the type of request: instruction fetch, memory read or write, etc. For a complete listing, see byutr.h.

Size Field

The size or length field contains the size of the data transfer in bytes.

Attribute Field

The attribute field is one byte long and refers to the cacheability of the block. In complete address traces all instruction fetches and data reads are noncacheable because the first-level instruction and data caches are disabled. In trace data that is acquired with the first-level caches enabled only those references that are truly noncacheable are marked as such. The lowest two bits have the following meaning:

	00	uncacheable
	01	write through
	10	write protect
	11	write back

Processor Field

The processor or agent id field tells which processor submitted the request. The value of this field varies in a multiprocessor system and remains constant in a single processor system.

Time Field

The time field indicates the delta time since the last request in clock ticks.

b2a.c is a very simple piece of C source code that reads the binary traces and prints an ASCII representation to stdout. This may be useful as both an introductory tool and as further trace format specification. It requires byutr.h.