* [ltt-dev] PATCH [0/1]: Replace gettimeofday with clock_gettime
@ 2010-05-24 14:54 Nils Carlson
2010-05-25 14:31 ` Pierre-Marc Fournier
2010-05-26 16:33 ` Pierre-Marc Fournier
0 siblings, 2 replies; 4+ messages in thread
From: Nils Carlson @ 2010-05-24 14:54 UTC (permalink / raw)
This patch replaces gettimeofday with clock_gettime(CLOCK_MONOTONIC,)
Signed-off-by: Nils Carlson <nils.carlson at ludd.ltu.se>
diff --git a/include/ust/clock.h b/include/ust/clock.h
index d4b6a9d..bc26d26 100644
--- a/include/ust/clock.h
+++ b/include/ust/clock.h
@@ -18,6 +18,7 @@
#ifndef UST_CLOCK_H
#define UST_CLOCK_H
+#include <time.h>
#include <sys/time.h>
#include <ust/kcompat/kcompat.h>
@@ -25,7 +26,7 @@
/* There are two types of clocks that can be used.
- TSC based clock
- - gettimeofday() clock
+ - gettimeofday() clock - to guarantee monotonicity use clock_gettime
Microbenchmarks on Linux 2.6.30 on Core2 Duo 3GHz (functions are
inlined):
Calls (100000000) to tsc(): 4004035641 cycles or 40 cycles/call
@@ -41,13 +42,13 @@
static __inline__ u64 trace_clock_read64(void)
{
- struct timeval tv;
+ struct timespec ts;
u64 retval;
- gettimeofday(&tv, NULL);
- retval = tv.tv_sec;
+ clock_gettime(CLOCK_MONOTONIC, &ts);
+ retval = ts.tv_sec;
retval *= 1000000;
- retval += tv.tv_usec;
+ retval += ts.tv_nsec / 1000;
return retval;
}
diff --git a/libust/Makefile.am b/libust/Makefile.am
index 2de5857..e357ad1 100644
--- a/libust/Makefile.am
+++ b/libust/Makefile.am
@@ -27,6 +27,7 @@ libust_la_LDFLAGS = -no-undefined -version-info 0:0:0
libust_la_LIBADD = \
-lpthread \
+ -lrt \
$(top_builddir)/snprintf/libustsnprintf.la \
$(top_builddir)/libustcomm/libustcomm.la
^ permalink raw reply [flat|nested] 4+ messages in thread* [ltt-dev] PATCH [0/1]: Replace gettimeofday with clock_gettime
2010-05-24 14:54 [ltt-dev] PATCH [0/1]: Replace gettimeofday with clock_gettime Nils Carlson
@ 2010-05-25 14:31 ` Pierre-Marc Fournier
2010-05-25 19:38 ` Nils Carlson
2010-05-26 16:33 ` Pierre-Marc Fournier
1 sibling, 1 reply; 4+ messages in thread
From: Pierre-Marc Fournier @ 2010-05-25 14:31 UTC (permalink / raw)
Thanks, comments below.
On 05/24/2010 10:54 AM, Nils Carlson wrote:
> This patch replaces gettimeofday with clock_gettime(CLOCK_MONOTONIC,)
>
> Signed-off-by: Nils Carlson<nils.carlson at ludd.ltu.se>
>
> diff --git a/include/ust/clock.h b/include/ust/clock.h
> index d4b6a9d..bc26d26 100644
> --- a/include/ust/clock.h
> +++ b/include/ust/clock.h
> @@ -18,6 +18,7 @@
> #ifndef UST_CLOCK_H
> #define UST_CLOCK_H
>
> +#include<time.h>
> #include<sys/time.h>
> #include<ust/kcompat/kcompat.h>
>
> @@ -25,7 +26,7 @@
>
> /* There are two types of clocks that can be used.
> - TSC based clock
> - - gettimeofday() clock
> + - gettimeofday() clock - to guarantee monotonicity use clock_gettime
>
> Microbenchmarks on Linux 2.6.30 on Core2 Duo 3GHz (functions are
> inlined):
> Calls (100000000) to tsc(): 4004035641 cycles or 40 cycles/call
> @@ -41,13 +42,13 @@
>
> static __inline__ u64 trace_clock_read64(void)
> {
> - struct timeval tv;
> + struct timespec ts;
> u64 retval;
>
> - gettimeofday(&tv, NULL);
> - retval = tv.tv_sec;
> + clock_gettime(CLOCK_MONOTONIC,&ts);
> + retval = ts.tv_sec;
> retval *= 1000000;
> - retval += tv.tv_usec;
> + retval += ts.tv_nsec / 1000;
Any specific reason for truncating the nanoseconds here?
>
> return retval;
> }
> diff --git a/libust/Makefile.am b/libust/Makefile.am
> index 2de5857..e357ad1 100644
> --- a/libust/Makefile.am
> +++ b/libust/Makefile.am
> @@ -27,6 +27,7 @@ libust_la_LDFLAGS = -no-undefined -version-info 0:0:0
>
> libust_la_LIBADD = \
> -lpthread \
> + -lrt \
I guess this isn't supposed to be part of the patch?
> $(top_builddir)/snprintf/libustsnprintf.la \
> $(top_builddir)/libustcomm/libustcomm.la
>
>
>
>
>
> _______________________________________________
> ltt-dev mailing list
> ltt-dev at lists.casi.polymtl.ca
> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
^ permalink raw reply [flat|nested] 4+ messages in thread* [ltt-dev] PATCH [0/1]: Replace gettimeofday with clock_gettime
2010-05-25 14:31 ` Pierre-Marc Fournier
@ 2010-05-25 19:38 ` Nils Carlson
0 siblings, 0 replies; 4+ messages in thread
From: Nils Carlson @ 2010-05-25 19:38 UTC (permalink / raw)
Comments below,
On May 25, 2010, at 4:31 PM, Pierre-Marc Fournier wrote:
> Thanks, comments below.
>
>
> On 05/24/2010 10:54 AM, Nils Carlson wrote:
>> This patch replaces gettimeofday with clock_gettime(CLOCK_MONOTONIC,)
>>
>> Signed-off-by: Nils Carlson<nils.carlson at ludd.ltu.se>
>>
>> diff --git a/include/ust/clock.h b/include/ust/clock.h
>> index d4b6a9d..bc26d26 100644
>> --- a/include/ust/clock.h
>> +++ b/include/ust/clock.h
>> @@ -18,6 +18,7 @@
>> #ifndef UST_CLOCK_H
>> #define UST_CLOCK_H
>>
>> +#include<time.h>
>> #include<sys/time.h>
>> #include<ust/kcompat/kcompat.h>
>>
>> @@ -25,7 +26,7 @@
>>
>> /* There are two types of clocks that can be used.
>> - TSC based clock
>> - - gettimeofday() clock
>> + - gettimeofday() clock - to guarantee monotonicity use
>> clock_gettime
>>
>> Microbenchmarks on Linux 2.6.30 on Core2 Duo 3GHz (functions are
>> inlined):
>> Calls (100000000) to tsc(): 4004035641 cycles or 40 cycles/call
>> @@ -41,13 +42,13 @@
>>
>> static __inline__ u64 trace_clock_read64(void)
>> {
>> - struct timeval tv;
>> + struct timespec ts;
>> u64 retval;
>>
>> - gettimeofday(&tv, NULL);
>> - retval = tv.tv_sec;
>> + clock_gettime(CLOCK_MONOTONIC,&ts);
>> + retval = ts.tv_sec;
>> retval *= 1000000;
>> - retval += tv.tv_usec;
>> + retval += ts.tv_nsec / 1000;
>
> Any specific reason for truncating the nanoseconds here?
Only to provide the same fidelity as the previous code. I don't know
enough
about how you use the timer, so I didn't take it upon myself to change
the
resolution.
>
>>
>> return retval;
>> }
>> diff --git a/libust/Makefile.am b/libust/Makefile.am
>> index 2de5857..e357ad1 100644
>> --- a/libust/Makefile.am
>> +++ b/libust/Makefile.am
>> @@ -27,6 +27,7 @@ libust_la_LDFLAGS = -no-undefined -version-info
>> 0:0:0
>>
>> libust_la_LIBADD = \
>> -lpthread \
>> + -lrt \
>
> I guess this isn't supposed to be part of the patch?
It is. clock_gettime requires the realtime clock library.
>
>> $(top_builddir)/snprintf/libustsnprintf.la \
>> $(top_builddir)/libustcomm/libustcomm.la
>>
>>
>>
>>
>>
>> _______________________________________________
>> ltt-dev mailing list
>> ltt-dev at lists.casi.polymtl.ca
>> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
^ permalink raw reply [flat|nested] 4+ messages in thread
* [ltt-dev] PATCH [0/1]: Replace gettimeofday with clock_gettime
2010-05-24 14:54 [ltt-dev] PATCH [0/1]: Replace gettimeofday with clock_gettime Nils Carlson
2010-05-25 14:31 ` Pierre-Marc Fournier
@ 2010-05-26 16:33 ` Pierre-Marc Fournier
1 sibling, 0 replies; 4+ messages in thread
From: Pierre-Marc Fournier @ 2010-05-26 16:33 UTC (permalink / raw)
Merged manually because the patch was corrupt. Perhaps due to your user
agent?
Also modified things to use the full precision.
Thanks!
pmf
Nils Carlson wrote:
> This patch replaces gettimeofday with clock_gettime(CLOCK_MONOTONIC,)
>
> Signed-off-by: Nils Carlson <nils.carlson at ludd.ltu.se>
>
> diff --git a/include/ust/clock.h b/include/ust/clock.h
> index d4b6a9d..bc26d26 100644
> --- a/include/ust/clock.h
> +++ b/include/ust/clock.h
> @@ -18,6 +18,7 @@
> #ifndef UST_CLOCK_H
> #define UST_CLOCK_H
>
> +#include <time.h>
> #include <sys/time.h>
> #include <ust/kcompat/kcompat.h>
>
> @@ -25,7 +26,7 @@
>
> /* There are two types of clocks that can be used.
> - TSC based clock
> - - gettimeofday() clock
> + - gettimeofday() clock - to guarantee monotonicity use clock_gettime
>
> Microbenchmarks on Linux 2.6.30 on Core2 Duo 3GHz (functions are
> inlined):
> Calls (100000000) to tsc(): 4004035641 cycles or 40 cycles/call
> @@ -41,13 +42,13 @@
>
> static __inline__ u64 trace_clock_read64(void)
> {
> - struct timeval tv;
> + struct timespec ts;
> u64 retval;
>
> - gettimeofday(&tv, NULL);
> - retval = tv.tv_sec;
> + clock_gettime(CLOCK_MONOTONIC, &ts);
> + retval = ts.tv_sec;
> retval *= 1000000;
> - retval += tv.tv_usec;
> + retval += ts.tv_nsec / 1000;
>
> return retval;
> }
> diff --git a/libust/Makefile.am b/libust/Makefile.am
> index 2de5857..e357ad1 100644
> --- a/libust/Makefile.am
> +++ b/libust/Makefile.am
> @@ -27,6 +27,7 @@ libust_la_LDFLAGS = -no-undefined -version-info 0:0:0
>
> libust_la_LIBADD = \
> -lpthread \
> + -lrt \
> $(top_builddir)/snprintf/libustsnprintf.la \
> $(top_builddir)/libustcomm/libustcomm.la
>
>
>
>
>
> _______________________________________________
> ltt-dev mailing list
> ltt-dev at lists.casi.polymtl.ca
> http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
^ permalink raw reply [flat|nested] 4+ messages in thread
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2010-05-24 14:54 [ltt-dev] PATCH [0/1]: Replace gettimeofday with clock_gettime Nils Carlson
2010-05-25 14:31 ` Pierre-Marc Fournier
2010-05-25 19:38 ` Nils Carlson
2010-05-26 16:33 ` Pierre-Marc Fournier
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