delaytop: enhance error logging and add PSI feature description

This patch improves error diagnostics and documentation for delaytop:

1) Enhanced error logging:
   - Added explicit error messages in critical failure paths
   - Implemented BOOL_FPRINT macro for robust output handling

2) PSI feature documentation:
   - Updated header comment to reflect PSI monitoring capability
   - Improved output formatting for PSI information

System Pressure Information: (avg10/avg60/avg300/total)
CPU some:       0.0%/   0.0%/   0.0%/     345(ms)
CPU full:       0.0%/   0.0%/   0.0%/       0(ms)
Memory full:    0.0%/   0.0%/   0.0%/       0(ms)
Memory some:    0.0%/   0.0%/   0.0%/       0(ms)
IO full:        0.0%/   0.0%/   0.0%/      65(ms)
IO some:        0.0%/   0.0%/   0.0%/      79(ms)
IRQ full:       0.0%/   0.0%/   0.0%/       0(ms)

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Fan Yu <[email protected]>
Signed-off-by: Wang Yaxin <[email protected]>
Acked-by: Yang Yang <[email protected]>
Cc: Fan Yu <[email protected]>
Cc: Jonathan Corbet <[email protected]>
Cc: xu xin <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions