diff options
| author | Steven Rostedt <rostedt@goodmis.org> | 2021-06-22 16:42:26 +0200 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2021-06-25 18:26:12 -0400 |
| commit | 62de4f29e9174e67beb8d34ef5ced6730e087a31 (patch) | |
| tree | 7b2ea1536311d62a2565484dcff01f68cee78c59 /include/trace/trace_events.h | |
| parent | aa892f8c887dd4331458d04de9425cde6664c694 (diff) | |
trace: Add __print_ns_to_secs() and __print_ns_without_secs() helpers
To have nanosecond output displayed in a more human readable format, its
nicer to convert it to a seconds format (XXX.YYYYYYYYY). The problem is that
to do so, the numbers must be divided by NSEC_PER_SEC, and moded too. But as
these numbers are 64 bit, this can not be done simply with '/' and '%'
operators, but must use do_div() instead.
Instead of performing the expensive do_div() in the hot path of the
tracepoint, it is more efficient to perform it during the output phase. But
passing in do_div() can confuse the parser, and do_div() doesn't work
exactly like a normal C function. It modifies the number in place, and we
don't want to modify the actual values in the ring buffer.
Two helper functions are now created:
__print_ns_to_secs() and __print_ns_without_secs()
They both take a value of nanoseconds, and the former will return that
number divided by NSEC_PER_SEC, and the latter will mod it with NSEC_PER_SEC
giving a way to print a nice human readable format:
__print_fmt("time=%llu.%09u",
__print_ns_to_secs(REC->nsec_val),
__print_ns_without_secs(REC->nsec_val))
Link: https://lkml.kernel.org/r/e503b903045496c4ccde52843e1e318b422f7a56.1624372313.git.bristot@redhat.com
Cc: Phil Auld <pauld@redhat.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Kate Carcia <kcarcia@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Alexandre Chartre <alexandre.chartre@oracle.com>
Cc: Clark Willaims <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: x86@kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@redhat.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'include/trace/trace_events.h')
| -rw-r--r-- | include/trace/trace_events.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/include/trace/trace_events.h b/include/trace/trace_events.h index 8268bf747d6f..acc17194c160 100644 --- a/include/trace/trace_events.h +++ b/include/trace/trace_events.h @@ -358,6 +358,21 @@ TRACE_MAKE_SYSTEM_STR(); trace_print_hex_dump_seq(p, prefix_str, prefix_type, \ rowsize, groupsize, buf, len, ascii) +#undef __print_ns_to_secs +#define __print_ns_to_secs(value) \ + ({ \ + u64 ____val = (u64)(value); \ + do_div(____val, NSEC_PER_SEC); \ + ____val; \ + }) + +#undef __print_ns_without_secs +#define __print_ns_without_secs(value) \ + ({ \ + u64 ____val = (u64)(value); \ + (u32) do_div(____val, NSEC_PER_SEC); \ + }) + #undef DECLARE_EVENT_CLASS #define DECLARE_EVENT_CLASS(call, proto, args, tstruct, assign, print) \ static notrace enum print_line_t \ @@ -736,6 +751,16 @@ static inline void ftrace_test_probe_##call(void) \ #undef __print_array #undef __print_hex_dump +/* + * The below is not executed in the kernel. It is only what is + * displayed in the print format for userspace to parse. + */ +#undef __print_ns_to_secs +#define __print_ns_to_secs(val) (val) / 1000000000UL + +#undef __print_ns_without_secs +#define __print_ns_without_secs(val) (val) % 1000000000UL + #undef TP_printk #define TP_printk(fmt, args...) "\"" fmt "\", " __stringify(args) |