dtrace: internal performance measurement support code

The dt_perf provider implements a few probes that are used in performance
(or more accurately put, overhead) measurements.  It uses an ioctl()
interface to trigger N-count interations of invoking probes through
various mechanisms, and a probe to post the results back to userspace.
This code also adds an SDT probe in the DTrace kernel support code, just
to measure overhead for triggering trap based SDT probes.

Signed-off-by: Kris Van Hees <kris.van.hees@oracle.com>

diff --git a/kernel/dtrace/Kconfig b/kernel/dtrace/Kconfig
index 363f8c8406c90fcf31ba1cafb5dc75249f1e616f..8411d527b46a44cef6ad0bd8cb9e45d248cfe509 100644 (file)
--- a/kernel/dtrace/Kconfig
+++ b/kernel/dtrace/Kconfig
@@ -69,6 +69,12 @@ config DT_DT_TEST
        help
          To be written.
 
+config DT_DT_PERF
+       tristate "DTrace Performance Test Probe"
+       default m
+       help
+         To be written.
+
 config DT_DEBUG
        bool "DTrace debugging"
        default m

diff --git a/kernel/dtrace/dtrace_sdt.c b/kernel/dtrace/dtrace_sdt.c
index a99d5c318e920081b50ad213b20b51d23ab87ada..0844941de070bef82ceafe4e0e7961d4966857a8 100644 (file)
--- a/kernel/dtrace/dtrace_sdt.c
+++ b/kernel/dtrace/dtrace_sdt.c
@@ -150,3 +150,11 @@ static int __init nosdt(char *str)
 }
 
 early_param("nosdt", nosdt);
+
+#if defined(CONFIG_DT_DT_PERF) || defined(CONFIG_DT_DT_PERF_MODULE)
+void dtrace_sdt_perf(void)
+{
+       DTRACE_PROBE(measure);
+}
+EXPORT_SYMBOL(dtrace_sdt_perf);
+#endif