Allocating Static Patch Space
TotalView can statically allocate patch space if you add a specially named array to your program. When TotalView needs to use patch space, it uses the space created for this array.
You can include, for example, a 1 MB statically allocated patch space in your program by adding the TVDB_patch_base_address data object in a C module. Because this object must be 8-byte aligned, declare it as an array of doubles; for example:
/* 1 megabyte == size TV expects */
#define PATCH_LEN 0x100000
double TVDB_patch_base_address [PATCH_LEN / sizeof(double)]
If you need to use a static patch space size that differs from the 1 MB default, you must use assembler language. The following table shows sample assembler code for IBM AIX-Power and Blue Gene/Q:
Platform | Assembler Code |
|---|
IBM AIX-Power | .csect .data{RW}, 3 .globl TVDB_patch_base_address .globl TVDB_patch_end_address TVDB_patch_base_address: .space PATCH_SIZE TVDB_patch_end_address: |
Blue Gene/Q | .section .TVDB_patch_space,"awx" .globl TVDB_patch_base_address .globl TVDB_patch_end_address TVDB_patch_base_address: .space 1024*1024,0 TVDB_patch_end_address: .previous |
To use the static patch space assembler code:
1. Use an ASCII editor and place the assembler code into a file named tvdb_patch_space.s.
2. Replace the PATCH_SIZE tag with the decimal number of bytes you want. This value must be a multiple of 8.
3. Assemble the file into an object file by using a command such as:
cc -c tvdb_patch_space.s
4. Link the resulting tvdb_patch_space.o into your program.
