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The
function enables or disables program counter profiling of the current
process. If profiling is enabled, then at every clock tick, the kernel updates
an appropriate count in the buffer. The buffer contains bytes and is
divided into a series of 16-bit bins. Each bin counts the number of times
the program counter was in a particular address range in the process when
a clock tick occurred while profiling was enabled. For a given program counter
address, the number of the corresponding bin is given by the relation:
[(pc - offset) / 2] * scale / 65536 The parameter is the lowest address
at which the kernel takes program counter samples. The parameter ranges
from 1 to 65536 and can be used to change the span of the bins. A scale
of 65536 maps each bin to 2 bytes of address range; a scale of 32768 gives
4 bytes, 16384 gives 8 bytes and so on. Intermediate values provide approximate
intermediate ranges. A value of 0 disables profiling.
If the
value is nonzero and the buffer contains an illegal address, returns
-1, profiling is terminated and is set appropriately. Otherwise returns
0.
profiling C run-time startup file conventional name for profiling
output file
The following error may be reported: The buffer contains
an invalid address.
This routine should be named The
argument should really be a vector of type The format of the gmon.out
file is undocumented.
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