* (forw) [RFC patch 08/15] LTTng - Timestamping
@ 2008-10-17 16:58 Mathieu Desnoyers
2008-10-18 22:14 ` Masami Hiramatsu
0 siblings, 1 reply; 5+ messages in thread
From: Mathieu Desnoyers @ 2008-10-17 16:58 UTC (permalink / raw)
To: ltt-dev, mbligh, systemtap
Hello,
Too many CCs on this last post. I should probably have added some, but
here is a link to the thread :
http://lkml.org/lkml/2008/10/16/511
Comments are welcome.
Mathieu
----- Forwarded message from Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> -----
Date: Thu, 16 Oct 2008 19:27:37 -0400
To: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org,
linux-arch@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Thomas Gleixner <tglx@linutronix.de>
Cc: David Miller <davem@davemloft.net>,
Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
Ralf Baechle <ralf@linux-mips.org>, benh@kernel.crashing.org,
paulus@samba.org, Ingo Molnar <mingo@redhat.com>
User-Agent: quilt/0.46-1
From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
Subject: [RFC patch 08/15] LTTng - Timestamping
Wrapper to use the lower level clock sources available on the systems. Fall-back
on jiffies or'd with a logical clock for architectures lacking CPU timestamp
counters. Fall-back on a mixed TSC-logical clock on architectures lacking
synchronized TSC on SMP.
A generic fallback based on a logical clock and the timer interrupt is
available.
generic - Uses jiffies or'd with a logical clock extended to 64 bits by
ltt-timestamp.c.
i386 - Uses TSC. If detects non synchronized TSC, uses mixed TSC-logical clock.
mips - Uses TSC extended atomically from 32 to 64 bits by ltt-heartbeat.c.
powerpc - Uses TSC or generic ltt clock.
x86_64 - Uses TSC. If detects non synchronized TSC, uses mixed TSC-logical clock
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: Ralf Baechle <ralf@linux-mips.org>
CC: benh@kernel.crashing.org
CC: paulus@samba.org
CC: David Miller <davem@davemloft.net>
CC: Linus Torvalds <torvalds@linux-foundation.org>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Ingo Molnar <mingo@redhat.com>
CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Steven Rostedt <rostedt@goodmis.org>
CC: linux-arch@vger.kernel.org
---
include/asm-generic/ltt.h | 53 ++++++++++++++++++++++++++++++++++++++++++++++
include/linux/ltt.h | 27 +++++++++++++++++++++++
kernel/timer.c | 2 +
3 files changed, 82 insertions(+)
Index: linux-2.6-lttng/kernel/timer.c
===================================================================
--- linux-2.6-lttng.orig/kernel/timer.c 2008-09-16 14:50:15.000000000 -0400
+++ linux-2.6-lttng/kernel/timer.c 2008-09-16 14:59:17.000000000 -0400
@@ -37,6 +37,7 @@
#include <linux/delay.h>
#include <linux/tick.h>
#include <linux/kallsyms.h>
+#include <linux/ltt.h>
#include <asm/uaccess.h>
#include <asm/unistd.h>
@@ -1066,6 +1067,7 @@ void do_timer(unsigned long ticks)
{
jiffies_64 += ticks;
update_times(ticks);
+ ltt_add_timestamp(ticks);
}
#ifdef __ARCH_WANT_SYS_ALARM
Index: linux-2.6-lttng/include/linux/ltt.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng/include/linux/ltt.h 2008-09-16 14:58:47.000000000 -0400
@@ -0,0 +1,27 @@
+#ifndef _LINUX_LTT_H
+#define _LINUX_LTT_H
+
+/*
+ * Generic LTT clock.
+ *
+ * Chooses between an architecture specific clock or an atomic logical clock.
+ *
+ * Copyright (C) 2007 Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
+ */
+
+#ifdef CONFIG_LTT_TIMESTAMP
+#ifdef CONFIG_HAVE_LTT_CLOCK
+#include <asm/ltt.h>
+#else
+#include <asm-generic/ltt.h>
+
+#define ltt_get_timestamp32 ltt_get_timestamp32_generic
+#define ltt_get_timestamp64 ltt_get_timestamp64_generic
+#define ltt_add_timestamp ltt_add_timestamp_generic
+#define ltt_frequency ltt_frequency_generic
+#define ltt_freq_scale ltt_freq_scale_generic
+#endif /* CONFIG_HAVE_LTT_CLOCK */
+#else
+#define ltt_add_timestamp(ticks)
+#endif /* CONFIG_LTT_TIMESTAMP */
+#endif /* _LINUX_LTT_H */
Index: linux-2.6-lttng/include/asm-generic/ltt.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng/include/asm-generic/ltt.h 2008-09-16 14:58:47.000000000 -0400
@@ -0,0 +1,53 @@
+#ifndef _ASM_GENERIC_LTT_H
+#define _ASM_GENERIC_LTT_H
+
+/*
+ * linux/include/asm-generic/ltt.h
+ *
+ * Copyright (C) 2007 - Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
+ *
+ * Generic definitions for LTT
+ * Architectures without TSC
+ */
+
+#include <linux/param.h> /* For HZ */
+#include <asm/atomic.h>
+
+#define LTT_GENERIC_CLOCK_SHIFT 13
+
+u64 ltt_read_synthetic_tsc(void);
+
+extern atomic_t lttng_generic_clock;
+
+static inline u32 ltt_get_timestamp32_generic(void)
+{
+ return atomic_add_return(1, <tng_generic_clock);
+}
+
+static inline u64 ltt_get_timestamp64_generic(void)
+{
+ return ltt_read_synthetic_tsc();
+}
+
+static inline void ltt_add_timestamp_generic(unsigned long ticks)
+{
+ int old_clock, new_clock;
+
+ do {
+ old_clock = atomic_read(<tng_generic_clock);
+ new_clock = (old_clock + (ticks << LTT_GENERIC_CLOCK_SHIFT))
+ & (~((1 << LTT_GENERIC_CLOCK_SHIFT) - 1));
+ } while (atomic_cmpxchg(<tng_generic_clock, old_clock, new_clock)
+ != old_clock);
+}
+
+static inline unsigned int ltt_frequency_generic(void)
+{
+ return HZ << LTT_GENERIC_CLOCK_SHIFT;
+}
+
+static inline u32 ltt_freq_scale_generic(void)
+{
+ return 1;
+}
+#endif /* _ASM_GENERIC_LTT_H */
--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
----- End forwarded message -----
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: (forw) [RFC patch 08/15] LTTng - Timestamping
2008-10-17 16:58 (forw) [RFC patch 08/15] LTTng - Timestamping Mathieu Desnoyers
@ 2008-10-18 22:14 ` Masami Hiramatsu
2008-10-20 15:50 ` [ltt-dev] " Mathieu Desnoyers
2008-10-22 16:27 ` Mathieu Desnoyers
0 siblings, 2 replies; 5+ messages in thread
From: Masami Hiramatsu @ 2008-10-18 22:14 UTC (permalink / raw)
To: Mathieu Desnoyers; +Cc: ltt-dev, mbligh, systemtap
Hi Mathieu,
These patches seems generally good. However, I wonder why you added
"ltt_" prefix. if it was useful for other parts of the kernel
(I think so), more general name(generic_timestamp?) would be preferable :)
Thank you,
Mathieu Desnoyers wrote:
> Hello,
>
> Too many CCs on this last post. I should probably have added some, but
> here is a link to the thread :
>
> http://lkml.org/lkml/2008/10/16/511
>
> Comments are welcome.
>
> Mathieu
>
> ----- Forwarded message from Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca> -----
>
> Date: Thu, 16 Oct 2008 19:27:37 -0400
> To: Linus Torvalds <torvalds@linux-foundation.org>,
> Andrew Morton <akpm@linux-foundation.org>,
> Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org,
> linux-arch@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>,
> Peter Zijlstra <a.p.zijlstra@chello.nl>,
> Thomas Gleixner <tglx@linutronix.de>
> Cc: David Miller <davem@davemloft.net>,
> Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
> Ralf Baechle <ralf@linux-mips.org>, benh@kernel.crashing.org,
> paulus@samba.org, Ingo Molnar <mingo@redhat.com>
> User-Agent: quilt/0.46-1
> From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> Subject: [RFC patch 08/15] LTTng - Timestamping
>
> Wrapper to use the lower level clock sources available on the systems. Fall-back
> on jiffies or'd with a logical clock for architectures lacking CPU timestamp
> counters. Fall-back on a mixed TSC-logical clock on architectures lacking
> synchronized TSC on SMP.
>
> A generic fallback based on a logical clock and the timer interrupt is
> available.
>
> generic - Uses jiffies or'd with a logical clock extended to 64 bits by
> ltt-timestamp.c.
> i386 - Uses TSC. If detects non synchronized TSC, uses mixed TSC-logical clock.
> mips - Uses TSC extended atomically from 32 to 64 bits by ltt-heartbeat.c.
> powerpc - Uses TSC or generic ltt clock.
> x86_64 - Uses TSC. If detects non synchronized TSC, uses mixed TSC-logical clock
>
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
> CC: Ralf Baechle <ralf@linux-mips.org>
> CC: benh@kernel.crashing.org
> CC: paulus@samba.org
> CC: David Miller <davem@davemloft.net>
> CC: Linus Torvalds <torvalds@linux-foundation.org>
> CC: Andrew Morton <akpm@linux-foundation.org>
> CC: Ingo Molnar <mingo@redhat.com>
> CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
> CC: Thomas Gleixner <tglx@linutronix.de>
> CC: Steven Rostedt <rostedt@goodmis.org>
> CC: linux-arch@vger.kernel.org
> ---
> include/asm-generic/ltt.h | 53 ++++++++++++++++++++++++++++++++++++++++++++++
> include/linux/ltt.h | 27 +++++++++++++++++++++++
> kernel/timer.c | 2 +
> 3 files changed, 82 insertions(+)
>
> Index: linux-2.6-lttng/kernel/timer.c
> ===================================================================
> --- linux-2.6-lttng.orig/kernel/timer.c 2008-09-16 14:50:15.000000000 -0400
> +++ linux-2.6-lttng/kernel/timer.c 2008-09-16 14:59:17.000000000 -0400
> @@ -37,6 +37,7 @@
> #include <linux/delay.h>
> #include <linux/tick.h>
> #include <linux/kallsyms.h>
> +#include <linux/ltt.h>
>
> #include <asm/uaccess.h>
> #include <asm/unistd.h>
> @@ -1066,6 +1067,7 @@ void do_timer(unsigned long ticks)
> {
> jiffies_64 += ticks;
> update_times(ticks);
> + ltt_add_timestamp(ticks);
> }
>
> #ifdef __ARCH_WANT_SYS_ALARM
> Index: linux-2.6-lttng/include/linux/ltt.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6-lttng/include/linux/ltt.h 2008-09-16 14:58:47.000000000 -0400
> @@ -0,0 +1,27 @@
> +#ifndef _LINUX_LTT_H
> +#define _LINUX_LTT_H
> +
> +/*
> + * Generic LTT clock.
> + *
> + * Chooses between an architecture specific clock or an atomic logical clock.
> + *
> + * Copyright (C) 2007 Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
> + */
> +
> +#ifdef CONFIG_LTT_TIMESTAMP
> +#ifdef CONFIG_HAVE_LTT_CLOCK
> +#include <asm/ltt.h>
> +#else
> +#include <asm-generic/ltt.h>
> +
> +#define ltt_get_timestamp32 ltt_get_timestamp32_generic
> +#define ltt_get_timestamp64 ltt_get_timestamp64_generic
> +#define ltt_add_timestamp ltt_add_timestamp_generic
> +#define ltt_frequency ltt_frequency_generic
> +#define ltt_freq_scale ltt_freq_scale_generic
> +#endif /* CONFIG_HAVE_LTT_CLOCK */
> +#else
> +#define ltt_add_timestamp(ticks)
> +#endif /* CONFIG_LTT_TIMESTAMP */
> +#endif /* _LINUX_LTT_H */
> Index: linux-2.6-lttng/include/asm-generic/ltt.h
> ===================================================================
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ linux-2.6-lttng/include/asm-generic/ltt.h 2008-09-16 14:58:47.000000000 -0400
> @@ -0,0 +1,53 @@
> +#ifndef _ASM_GENERIC_LTT_H
> +#define _ASM_GENERIC_LTT_H
> +
> +/*
> + * linux/include/asm-generic/ltt.h
> + *
> + * Copyright (C) 2007 - Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
> + *
> + * Generic definitions for LTT
> + * Architectures without TSC
> + */
> +
> +#include <linux/param.h> /* For HZ */
> +#include <asm/atomic.h>
> +
> +#define LTT_GENERIC_CLOCK_SHIFT 13
> +
> +u64 ltt_read_synthetic_tsc(void);
> +
> +extern atomic_t lttng_generic_clock;
> +
> +static inline u32 ltt_get_timestamp32_generic(void)
> +{
> + return atomic_add_return(1, <tng_generic_clock);
> +}
> +
> +static inline u64 ltt_get_timestamp64_generic(void)
> +{
> + return ltt_read_synthetic_tsc();
> +}
> +
> +static inline void ltt_add_timestamp_generic(unsigned long ticks)
> +{
> + int old_clock, new_clock;
> +
> + do {
> + old_clock = atomic_read(<tng_generic_clock);
> + new_clock = (old_clock + (ticks << LTT_GENERIC_CLOCK_SHIFT))
> + & (~((1 << LTT_GENERIC_CLOCK_SHIFT) - 1));
> + } while (atomic_cmpxchg(<tng_generic_clock, old_clock, new_clock)
> + != old_clock);
> +}
> +
> +static inline unsigned int ltt_frequency_generic(void)
> +{
> + return HZ << LTT_GENERIC_CLOCK_SHIFT;
> +}
> +
> +static inline u32 ltt_freq_scale_generic(void)
> +{
> + return 1;
> +}
> +#endif /* _ASM_GENERIC_LTT_H */
>
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [ltt-dev] (forw) [RFC patch 08/15] LTTng - Timestamping
2008-10-18 22:14 ` Masami Hiramatsu
@ 2008-10-20 15:50 ` Mathieu Desnoyers
2008-10-22 16:27 ` Mathieu Desnoyers
1 sibling, 0 replies; 5+ messages in thread
From: Mathieu Desnoyers @ 2008-10-20 15:50 UTC (permalink / raw)
To: Masami Hiramatsu; +Cc: ltt-dev, mbligh, systemtap
Yeah, well I had this stuff in the LTTng tree for about 3 years, so I
kept everything under my own namespace. I like Ingo's idea of
"trace_clock()". I'll probably change the namespace to this, and move
the files from /ltt/* to /kernel/trace/*.
Mathieu
* Masami Hiramatsu (mhiramat@redhat.com) wrote:
> Hi Mathieu,
>
> These patches seems generally good. However, I wonder why you added
> "ltt_" prefix. if it was useful for other parts of the kernel
> (I think so), more general name(generic_timestamp?) would be preferable :)
>
> Thank you,
>
> Mathieu Desnoyers wrote:
>> Hello,
>> Too many CCs on this last post. I should probably have added some, but
>> here is a link to the thread :
>> http://lkml.org/lkml/2008/10/16/511
>> Comments are welcome.
>> Mathieu
>> ----- Forwarded message from Mathieu Desnoyers
>> <mathieu.desnoyers@polymtl.ca> -----
>> Date: Thu, 16 Oct 2008 19:27:37 -0400
>> To: Linus Torvalds <torvalds@linux-foundation.org>,
>> Andrew Morton <akpm@linux-foundation.org>,
>> Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org,
>> linux-arch@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>,
>> Peter Zijlstra <a.p.zijlstra@chello.nl>,
>> Thomas Gleixner <tglx@linutronix.de>
>> Cc: David Miller <davem@davemloft.net>,
>> Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
>> Ralf Baechle <ralf@linux-mips.org>, benh@kernel.crashing.org,
>> paulus@samba.org, Ingo Molnar <mingo@redhat.com>
>> User-Agent: quilt/0.46-1
>> From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
>> Subject: [RFC patch 08/15] LTTng - Timestamping
>> Wrapper to use the lower level clock sources available on the systems.
>> Fall-back
>> on jiffies or'd with a logical clock for architectures lacking CPU
>> timestamp
>> counters. Fall-back on a mixed TSC-logical clock on architectures lacking
>> synchronized TSC on SMP.
>> A generic fallback based on a logical clock and the timer interrupt is
>> available.
>> generic - Uses jiffies or'd with a logical clock extended to 64 bits by
>> ltt-timestamp.c.
>> i386 - Uses TSC. If detects non synchronized TSC, uses mixed TSC-logical
>> clock.
>> mips - Uses TSC extended atomically from 32 to 64 bits by ltt-heartbeat.c.
>> powerpc - Uses TSC or generic ltt clock.
>> x86_64 - Uses TSC. If detects non synchronized TSC, uses mixed TSC-logical
>> clock
>> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
>> CC: Ralf Baechle <ralf@linux-mips.org>
>> CC: benh@kernel.crashing.org
>> CC: paulus@samba.org
>> CC: David Miller <davem@davemloft.net>
>> CC: Linus Torvalds <torvalds@linux-foundation.org>
>> CC: Andrew Morton <akpm@linux-foundation.org>
>> CC: Ingo Molnar <mingo@redhat.com>
>> CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
>> CC: Thomas Gleixner <tglx@linutronix.de>
>> CC: Steven Rostedt <rostedt@goodmis.org>
>> CC: linux-arch@vger.kernel.org
>> ---
>> include/asm-generic/ltt.h | 53
>> ++++++++++++++++++++++++++++++++++++++++++++++
>> include/linux/ltt.h | 27 +++++++++++++++++++++++
>> kernel/timer.c | 2 +
>> 3 files changed, 82 insertions(+)
>> Index: linux-2.6-lttng/kernel/timer.c
>> ===================================================================
>> --- linux-2.6-lttng.orig/kernel/timer.c 2008-09-16 14:50:15.000000000
>> -0400
>> +++ linux-2.6-lttng/kernel/timer.c 2008-09-16 14:59:17.000000000 -0400
>> @@ -37,6 +37,7 @@
>> #include <linux/delay.h>
>> #include <linux/tick.h>
>> #include <linux/kallsyms.h>
>> +#include <linux/ltt.h>
>> #include <asm/uaccess.h>
>> #include <asm/unistd.h>
>> @@ -1066,6 +1067,7 @@ void do_timer(unsigned long ticks)
>> {
>> jiffies_64 += ticks;
>> update_times(ticks);
>> + ltt_add_timestamp(ticks);
>> }
>> #ifdef __ARCH_WANT_SYS_ALARM
>> Index: linux-2.6-lttng/include/linux/ltt.h
>> ===================================================================
>> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
>> +++ linux-2.6-lttng/include/linux/ltt.h 2008-09-16 14:58:47.000000000
>> -0400
>> @@ -0,0 +1,27 @@
>> +#ifndef _LINUX_LTT_H
>> +#define _LINUX_LTT_H
>> +
>> +/*
>> + * Generic LTT clock.
>> + *
>> + * Chooses between an architecture specific clock or an atomic logical
>> clock.
>> + *
>> + * Copyright (C) 2007 Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
>> + */
>> +
>> +#ifdef CONFIG_LTT_TIMESTAMP
>> +#ifdef CONFIG_HAVE_LTT_CLOCK
>> +#include <asm/ltt.h>
>> +#else
>> +#include <asm-generic/ltt.h>
>> +
>> +#define ltt_get_timestamp32 ltt_get_timestamp32_generic
>> +#define ltt_get_timestamp64 ltt_get_timestamp64_generic
>> +#define ltt_add_timestamp ltt_add_timestamp_generic
>> +#define ltt_frequency ltt_frequency_generic
>> +#define ltt_freq_scale ltt_freq_scale_generic
>> +#endif /* CONFIG_HAVE_LTT_CLOCK */
>> +#else
>> +#define ltt_add_timestamp(ticks)
>> +#endif /* CONFIG_LTT_TIMESTAMP */
>> +#endif /* _LINUX_LTT_H */
>> Index: linux-2.6-lttng/include/asm-generic/ltt.h
>> ===================================================================
>> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
>> +++ linux-2.6-lttng/include/asm-generic/ltt.h 2008-09-16
>> 14:58:47.000000000 -0400
>> @@ -0,0 +1,53 @@
>> +#ifndef _ASM_GENERIC_LTT_H
>> +#define _ASM_GENERIC_LTT_H
>> +
>> +/*
>> + * linux/include/asm-generic/ltt.h
>> + *
>> + * Copyright (C) 2007 - Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
>> + *
>> + * Generic definitions for LTT
>> + * Architectures without TSC
>> + */
>> +
>> +#include <linux/param.h> /* For HZ */
>> +#include <asm/atomic.h>
>> +
>> +#define LTT_GENERIC_CLOCK_SHIFT 13
>> +
>> +u64 ltt_read_synthetic_tsc(void);
>> +
>> +extern atomic_t lttng_generic_clock;
>> +
>> +static inline u32 ltt_get_timestamp32_generic(void)
>> +{
>> + return atomic_add_return(1, <tng_generic_clock);
>> +}
>> +
>> +static inline u64 ltt_get_timestamp64_generic(void)
>> +{
>> + return ltt_read_synthetic_tsc();
>> +}
>> +
>> +static inline void ltt_add_timestamp_generic(unsigned long ticks)
>> +{
>> + int old_clock, new_clock;
>> +
>> + do {
>> + old_clock = atomic_read(<tng_generic_clock);
>> + new_clock = (old_clock + (ticks << LTT_GENERIC_CLOCK_SHIFT))
>> + & (~((1 << LTT_GENERIC_CLOCK_SHIFT) - 1));
>> + } while (atomic_cmpxchg(<tng_generic_clock, old_clock, new_clock)
>> + != old_clock);
>> +}
>> +
>> +static inline unsigned int ltt_frequency_generic(void)
>> +{
>> + return HZ << LTT_GENERIC_CLOCK_SHIFT;
>> +}
>> +
>> +static inline u32 ltt_freq_scale_generic(void)
>> +{
>> + return 1;
>> +}
>> +#endif /* _ASM_GENERIC_LTT_H */
>
> --
> Masami Hiramatsu
>
> Software Engineer
> Hitachi Computer Products (America) Inc.
> Software Solutions Division
>
> e-mail: mhiramat@redhat.com
>
>
> _______________________________________________
> ltt-dev mailing list
> ltt-dev@lists.casi.polymtl.ca
> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
>
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: (forw) [RFC patch 08/15] LTTng - Timestamping
2008-10-18 22:14 ` Masami Hiramatsu
2008-10-20 15:50 ` [ltt-dev] " Mathieu Desnoyers
@ 2008-10-22 16:27 ` Mathieu Desnoyers
2008-10-23 21:12 ` Masami Hiramatsu
1 sibling, 1 reply; 5+ messages in thread
From: Mathieu Desnoyers @ 2008-10-22 16:27 UTC (permalink / raw)
To: Masami Hiramatsu; +Cc: ltt-dev, mbligh, systemtap
Hi Masami,
I'll change to trace_clock (idea from Ingo). I originally created these
time sources as part of LTTng, it's the only reason why they have a ltt_
prefix. :)
Thanks for the review,
Mathieu
* Masami Hiramatsu (mhiramat@redhat.com) wrote:
> Hi Mathieu,
>
> These patches seems generally good. However, I wonder why you added
> "ltt_" prefix. if it was useful for other parts of the kernel
> (I think so), more general name(generic_timestamp?) would be preferable :)
>
> Thank you,
>
> Mathieu Desnoyers wrote:
>> Hello,
>> Too many CCs on this last post. I should probably have added some, but
>> here is a link to the thread :
>> http://lkml.org/lkml/2008/10/16/511
>> Comments are welcome.
>> Mathieu
>> ----- Forwarded message from Mathieu Desnoyers
>> <mathieu.desnoyers@polymtl.ca> -----
>> Date: Thu, 16 Oct 2008 19:27:37 -0400
>> To: Linus Torvalds <torvalds@linux-foundation.org>,
>> Andrew Morton <akpm@linux-foundation.org>,
>> Ingo Molnar <mingo@elte.hu>, linux-kernel@vger.kernel.org,
>> linux-arch@vger.kernel.org, Steven Rostedt <rostedt@goodmis.org>,
>> Peter Zijlstra <a.p.zijlstra@chello.nl>,
>> Thomas Gleixner <tglx@linutronix.de>
>> Cc: David Miller <davem@davemloft.net>,
>> Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>,
>> Ralf Baechle <ralf@linux-mips.org>, benh@kernel.crashing.org,
>> paulus@samba.org, Ingo Molnar <mingo@redhat.com>
>> User-Agent: quilt/0.46-1
>> From: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
>> Subject: [RFC patch 08/15] LTTng - Timestamping
>> Wrapper to use the lower level clock sources available on the systems.
>> Fall-back
>> on jiffies or'd with a logical clock for architectures lacking CPU
>> timestamp
>> counters. Fall-back on a mixed TSC-logical clock on architectures lacking
>> synchronized TSC on SMP.
>> A generic fallback based on a logical clock and the timer interrupt is
>> available.
>> generic - Uses jiffies or'd with a logical clock extended to 64 bits by
>> ltt-timestamp.c.
>> i386 - Uses TSC. If detects non synchronized TSC, uses mixed TSC-logical
>> clock.
>> mips - Uses TSC extended atomically from 32 to 64 bits by ltt-heartbeat.c.
>> powerpc - Uses TSC or generic ltt clock.
>> x86_64 - Uses TSC. If detects non synchronized TSC, uses mixed TSC-logical
>> clock
>> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
>> CC: Ralf Baechle <ralf@linux-mips.org>
>> CC: benh@kernel.crashing.org
>> CC: paulus@samba.org
>> CC: David Miller <davem@davemloft.net>
>> CC: Linus Torvalds <torvalds@linux-foundation.org>
>> CC: Andrew Morton <akpm@linux-foundation.org>
>> CC: Ingo Molnar <mingo@redhat.com>
>> CC: Peter Zijlstra <a.p.zijlstra@chello.nl>
>> CC: Thomas Gleixner <tglx@linutronix.de>
>> CC: Steven Rostedt <rostedt@goodmis.org>
>> CC: linux-arch@vger.kernel.org
>> ---
>> include/asm-generic/ltt.h | 53
>> ++++++++++++++++++++++++++++++++++++++++++++++
>> include/linux/ltt.h | 27 +++++++++++++++++++++++
>> kernel/timer.c | 2 +
>> 3 files changed, 82 insertions(+)
>> Index: linux-2.6-lttng/kernel/timer.c
>> ===================================================================
>> --- linux-2.6-lttng.orig/kernel/timer.c 2008-09-16 14:50:15.000000000
>> -0400
>> +++ linux-2.6-lttng/kernel/timer.c 2008-09-16 14:59:17.000000000 -0400
>> @@ -37,6 +37,7 @@
>> #include <linux/delay.h>
>> #include <linux/tick.h>
>> #include <linux/kallsyms.h>
>> +#include <linux/ltt.h>
>> #include <asm/uaccess.h>
>> #include <asm/unistd.h>
>> @@ -1066,6 +1067,7 @@ void do_timer(unsigned long ticks)
>> {
>> jiffies_64 += ticks;
>> update_times(ticks);
>> + ltt_add_timestamp(ticks);
>> }
>> #ifdef __ARCH_WANT_SYS_ALARM
>> Index: linux-2.6-lttng/include/linux/ltt.h
>> ===================================================================
>> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
>> +++ linux-2.6-lttng/include/linux/ltt.h 2008-09-16 14:58:47.000000000
>> -0400
>> @@ -0,0 +1,27 @@
>> +#ifndef _LINUX_LTT_H
>> +#define _LINUX_LTT_H
>> +
>> +/*
>> + * Generic LTT clock.
>> + *
>> + * Chooses between an architecture specific clock or an atomic logical
>> clock.
>> + *
>> + * Copyright (C) 2007 Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
>> + */
>> +
>> +#ifdef CONFIG_LTT_TIMESTAMP
>> +#ifdef CONFIG_HAVE_LTT_CLOCK
>> +#include <asm/ltt.h>
>> +#else
>> +#include <asm-generic/ltt.h>
>> +
>> +#define ltt_get_timestamp32 ltt_get_timestamp32_generic
>> +#define ltt_get_timestamp64 ltt_get_timestamp64_generic
>> +#define ltt_add_timestamp ltt_add_timestamp_generic
>> +#define ltt_frequency ltt_frequency_generic
>> +#define ltt_freq_scale ltt_freq_scale_generic
>> +#endif /* CONFIG_HAVE_LTT_CLOCK */
>> +#else
>> +#define ltt_add_timestamp(ticks)
>> +#endif /* CONFIG_LTT_TIMESTAMP */
>> +#endif /* _LINUX_LTT_H */
>> Index: linux-2.6-lttng/include/asm-generic/ltt.h
>> ===================================================================
>> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
>> +++ linux-2.6-lttng/include/asm-generic/ltt.h 2008-09-16
>> 14:58:47.000000000 -0400
>> @@ -0,0 +1,53 @@
>> +#ifndef _ASM_GENERIC_LTT_H
>> +#define _ASM_GENERIC_LTT_H
>> +
>> +/*
>> + * linux/include/asm-generic/ltt.h
>> + *
>> + * Copyright (C) 2007 - Mathieu Desnoyers (mathieu.desnoyers@polymtl.ca)
>> + *
>> + * Generic definitions for LTT
>> + * Architectures without TSC
>> + */
>> +
>> +#include <linux/param.h> /* For HZ */
>> +#include <asm/atomic.h>
>> +
>> +#define LTT_GENERIC_CLOCK_SHIFT 13
>> +
>> +u64 ltt_read_synthetic_tsc(void);
>> +
>> +extern atomic_t lttng_generic_clock;
>> +
>> +static inline u32 ltt_get_timestamp32_generic(void)
>> +{
>> + return atomic_add_return(1, <tng_generic_clock);
>> +}
>> +
>> +static inline u64 ltt_get_timestamp64_generic(void)
>> +{
>> + return ltt_read_synthetic_tsc();
>> +}
>> +
>> +static inline void ltt_add_timestamp_generic(unsigned long ticks)
>> +{
>> + int old_clock, new_clock;
>> +
>> + do {
>> + old_clock = atomic_read(<tng_generic_clock);
>> + new_clock = (old_clock + (ticks << LTT_GENERIC_CLOCK_SHIFT))
>> + & (~((1 << LTT_GENERIC_CLOCK_SHIFT) - 1));
>> + } while (atomic_cmpxchg(<tng_generic_clock, old_clock, new_clock)
>> + != old_clock);
>> +}
>> +
>> +static inline unsigned int ltt_frequency_generic(void)
>> +{
>> + return HZ << LTT_GENERIC_CLOCK_SHIFT;
>> +}
>> +
>> +static inline u32 ltt_freq_scale_generic(void)
>> +{
>> + return 1;
>> +}
>> +#endif /* _ASM_GENERIC_LTT_H */
>
> --
> Masami Hiramatsu
>
> Software Engineer
> Hitachi Computer Products (America) Inc.
> Software Solutions Division
>
> e-mail: mhiramat@redhat.com
>
--
Mathieu Desnoyers
OpenPGP key fingerprint: 8CD5 52C3 8E3C 4140 715F BA06 3F25 A8FE 3BAE 9A68
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: (forw) [RFC patch 08/15] LTTng - Timestamping
2008-10-22 16:27 ` Mathieu Desnoyers
@ 2008-10-23 21:12 ` Masami Hiramatsu
0 siblings, 0 replies; 5+ messages in thread
From: Masami Hiramatsu @ 2008-10-23 21:12 UTC (permalink / raw)
To: Mathieu Desnoyers; +Cc: ltt-dev, mbligh, systemtap
Hi Mathieu,
Mathieu Desnoyers wrote:
> Hi Masami,
>
> I'll change to trace_clock (idea from Ingo). I originally created these
> time sources as part of LTTng, it's the only reason why they have a ltt_
> prefix. :)
Great! then, it's time to move to trace_clock ;-)
Thank you for your work!
--
Masami Hiramatsu
Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division
e-mail: mhiramat@redhat.com
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2008-10-23 21:12 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2008-10-17 16:58 (forw) [RFC patch 08/15] LTTng - Timestamping Mathieu Desnoyers
2008-10-18 22:14 ` Masami Hiramatsu
2008-10-20 15:50 ` [ltt-dev] " Mathieu Desnoyers
2008-10-22 16:27 ` Mathieu Desnoyers
2008-10-23 21:12 ` Masami Hiramatsu
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