[RFC patch 10/15] LTTng timestamp mips

Mathieu Desnoyers
2008-10-17T00:05:05Z

[-- Attachment #1: lttng-timestamp-mips.patch --]
[-- Type: text/plain, Size: 2402 bytes --]

MIPS get_cycles only returns a 32 bits TSC (see timex.h). The assumption there
is that the reschedule is done every 8 seconds or so. Given that tracing needs
to detect delays longer than 8 seconds, we need a full 64-bits TSC, whic is
provided by LTTng syntheric TSC.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@polymtl.ca>
CC: Ralf Baechle <ralf@linux-mips.org>
---
arch/mips/Kconfig | 2 ++
include/asm-mips/ltt.h | 44 ++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 46 insertions(+)

Index: linux-2.6-lttng/include/asm-mips/ltt.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6-lttng/include/asm-mips/ltt.h 2008-10-16 19:18:48.000000000 -0400
@@ -0,0 +1,44 @@
+/*
+ * Copyright (C) 2005, Mathieu Desnoyers
+ *
+ * MIPS definitions for tracing system
+ */
+
+#ifndef _ASM_MIPS_LTT_H
+#define _ASM_MIPS_LTT_H
+
+#include <linux/timex.h>
+#include <asm/processor.h>
+
+extern u64 ltt_read_synthetic_tsc(void);
+
+/*
+ * MIPS get_cycles only returns a 32 bits TSC (see timex.h). The assumption
+ * there is that the reschedule is done every 8 seconds or so. Given that
+ * tracing needs to detect delays longer than 8 seconds, we need a full 64-bits
+ * TSC, whic is provided by LTTng syntheric TSC.
+*/
+static inline u32 ltt_get_timestamp32(void)
+{
+ return get_cycles();
+}
+
+static inline u64 ltt_get_timestamp64(void)
+{
+ return ltt_read_synthetic_tsc();
+}
+
+static inline void ltt_add_timestamp(unsigned long ticks)
+{ }
+
+static inline unsigned int ltt_frequency(void)
+{
+ return mips_hpt_frequency;
+}
+
+static inline u32 ltt_freq_scale(void)
+{
+ return 1;
+}
+
+#endif /* _ASM_MIPS_LTT_H */
Index: linux-2.6-lttng/arch/mips/Kconfig
===================================================================
--- linux-2.6-lttng.orig/arch/mips/Kconfig 2008-10-16 19:14:08.000000000 -0400
+++ linux-2.6-lttng/arch/mips/Kconfig 2008-10-16 19:16:49.000000000 -0400
@@ -1584,6 +1584,8 @@ config CPU_R4400_WORKAROUNDS
config HAVE_GET_CYCLES_32
def_bool y
depends on !CPU_R4400_WORKAROUNDS
+ select HAVE_LTT_CLOCK
+ select HAVE_LTT_SYNTHETIC_TSC

#
# Use the generic interrupt handling code in kernel/irq/:

--
Mathieu Desnoyers
Computer Engineering Ph.D. Student, Ecole Polytechnique de Montreal