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Diffstat (limited to 'docs/devel/tracing.txt')
| -rw-r--r-- | docs/devel/tracing.txt | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/docs/devel/tracing.txt b/docs/devel/tracing.txt index 07abbb345c..6f815ecbd7 100644 --- a/docs/devel/tracing.txt +++ b/docs/devel/tracing.txt @@ -104,6 +104,11 @@ Trace events should use types as follows: * For everything else, use primitive scalar types (char, int, long) with the appropriate signedness. + * Avoid floating point types (float and double) because SystemTap does not + support them. In most cases it is possible to round to an integer type + instead. This may require scaling the value first by multiplying it by 1000 + or the like when digits after the decimal point need to be preserved. + Format strings should reflect the types defined in the trace event. Take special care to use PRId64 and PRIu64 for int64_t and uint64_t types, respectively. This ensures portability between 32- and 64-bit platforms. |