From: Daniel Bristot de Oliveira <bristot@redhat.com>
To: linux-kernel@vger.kernel.org
Cc: Phil Auld <pauld@redhat.com>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Kate Carcia <kcarcia@redhat.com>,
Daniel Bristot de Oliveira <bristot@redhat.com>,
Jonathan Corbet <corbet@lwn.net>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Alexandre Chartre <alexandre.chartre@oracle.com>,
Clark Willaims <williams@redhat.com>,
John Kacur <jkacur@redhat.com>,
Juri Lelli <juri.lelli@redhat.com>,
linux-doc@vger.kernel.org
Subject: [PATCH V3 7/9] tracing: Add __print_ns_to_secs() and __print_ns_without_secs() helpers
Date: Fri, 14 May 2021 22:51:16 +0200 [thread overview]
Message-ID: <2c59beee3b36b15592bfbb9f26dee7f8b55fd814.1621024265.git.bristot@redhat.com> (raw)
In-Reply-To: <cover.1621024265.git.bristot@redhat.com>
From: Steven Rostedt <rostedt@goodmis.org>
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))
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Steven Rostedt <rostedt@goodmis.org>
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: 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>
---
include/trace/trace_events.h | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/include/trace/trace_events.h b/include/trace/trace_events.h
index 8268bf747d6f..248090415b97 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)
--
2.26.3
next prev parent reply other threads:[~2021-05-14 20:52 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-14 20:51 [PATCH V3 0/9] hwlat improvements and osnoise/timerlat tracers Daniel Bristot de Oliveira
2021-05-14 20:51 ` [PATCH V3 1/9] tracing/hwlat: Fix Clark's email Daniel Bristot de Oliveira
2021-05-14 20:51 ` [PATCH V3 2/9] tracing/hwlat: Implement the mode config option Daniel Bristot de Oliveira
2021-06-03 20:11 ` Steven Rostedt
2021-05-14 20:51 ` [PATCH V3 3/9] tracing/hwlat: Switch disable_migrate to mode none Daniel Bristot de Oliveira
2021-05-14 20:51 ` [PATCH V3 4/9] tracing/hwlat: Implement the per-cpu mode Daniel Bristot de Oliveira
2021-05-27 11:58 ` Juri Lelli
2021-05-27 12:29 ` Daniel Bristot de Oliveira
2021-06-03 21:17 ` Steven Rostedt
2021-06-04 15:31 ` Daniel Bristot de Oliveira
2021-05-14 20:51 ` [PATCH V3 5/9] tracing/trace: Add a generic function to read/write u64 values from tracefs Daniel Bristot de Oliveira
2021-06-03 21:22 ` Steven Rostedt
2021-06-04 16:05 ` Daniel Bristot de Oliveira
2021-06-04 16:18 ` Steven Rostedt
2021-06-04 16:34 ` Daniel Bristot de Oliveira
2021-05-14 20:51 ` [PATCH V3 6/9] trace/hwlat: Use the generic function to read/write width and window Daniel Bristot de Oliveira
2021-06-03 21:27 ` Steven Rostedt
2021-06-04 16:36 ` Daniel Bristot de Oliveira
2021-06-04 20:50 ` Steven Rostedt
2021-05-14 20:51 ` Daniel Bristot de Oliveira [this message]
2021-06-03 21:29 ` [PATCH V3 7/9] tracing: Add __print_ns_to_secs() and __print_ns_without_secs() helpers Steven Rostedt
2021-06-04 4:19 ` Joe Perches
2021-06-04 16:21 ` Steven Rostedt
2021-06-04 19:09 ` [PATCH] treewide: Add missing semicolons to __assign_str uses Joe Perches
2021-06-04 19:09 ` Joe Perches
2021-06-04 19:09 ` Joe Perches
2021-06-04 19:38 ` Joe Perches
2021-06-04 19:38 ` Joe Perches
2021-06-04 19:38 ` Joe Perches
2021-06-07 23:18 ` Jason Gunthorpe
2021-06-07 23:18 ` Jason Gunthorpe
2021-06-07 23:18 ` Jason Gunthorpe
2021-06-12 15:42 ` [PATCH V2] " Joe Perches
2021-06-12 15:42 ` Joe Perches
2021-06-12 15:42 ` Joe Perches
2021-06-12 23:11 ` Steven Rostedt
2021-06-12 23:11 ` Steven Rostedt
2021-06-12 23:11 ` Steven Rostedt
2021-06-30 11:28 ` Joe Perches
2021-06-30 11:28 ` Joe Perches
2021-06-30 11:28 ` Joe Perches
2021-06-30 12:22 ` Steven Rostedt
2021-06-30 12:22 ` Steven Rostedt
2021-06-30 12:22 ` Steven Rostedt
2021-06-04 16:07 ` [PATCH V3 7/9] tracing: Add __print_ns_to_secs() and __print_ns_without_secs() helpers Daniel Bristot de Oliveira
2021-05-14 20:51 ` [PATCH V3 8/9] tracing: Add osnoise tracer Daniel Bristot de Oliveira
2021-06-03 21:31 ` Steven Rostedt
2021-06-04 21:28 ` Steven Rostedt
2021-06-07 12:00 ` Daniel Bristot de Oliveira
2021-06-07 15:47 ` Steven Rostedt
2021-06-08 15:24 ` Daniel Bristot de Oliveira
2021-06-08 17:17 ` Daniel Bristot de Oliveira
2021-06-08 17:39 ` Steven Rostedt
2021-06-08 19:33 ` Daniel Bristot de Oliveira
2021-06-08 19:42 ` Steven Rostedt
2021-06-09 12:14 ` Daniel Bristot de Oliveira
2021-06-09 13:03 ` Steven Rostedt
2021-06-09 13:44 ` Daniel Bristot de Oliveira
2021-05-14 20:51 ` [PATCH V3 9/9] tracing: Add timerlat tracer Daniel Bristot de Oliveira
2021-06-08 1:36 ` Steven Rostedt
2021-06-11 12:59 ` Daniel Bristot de Oliveira
2021-06-11 20:03 ` Steven Rostedt
2021-06-12 9:41 ` Daniel Bristot de Oliveira
2021-06-12 23:06 ` Steven Rostedt
2021-06-11 14:13 ` Daniel Bristot de Oliveira
2021-06-11 20:48 ` Steven Rostedt
2021-06-12 8:47 ` Daniel Bristot de Oliveira
2021-06-12 23:09 ` Steven Rostedt
2021-06-15 8:18 ` Daniel Bristot de Oliveira
2021-05-27 12:07 ` [PATCH V3 0/9] hwlat improvements and osnoise/timerlat tracers Juri Lelli
2021-05-29 2:16 ` Steven Rostedt
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