* [PATCH] tools/powercap: Implement powercap_set_enabled()
@ 2025-05-10 18:47 Suchit Karunakaran
2025-05-13 22:03 ` Shuah Khan
0 siblings, 1 reply; 4+ messages in thread
From: Suchit Karunakaran @ 2025-05-10 18:47 UTC (permalink / raw)
To: trenn, shuah, jwyatt, jkacur, linux-pm
Cc: linux-kernel-mentees, linux-kernel, Suchit Karunakaran
The powercap_set_enabled() function previously returned a dummy value
and was marked with a TODO comment. This patch implements the function
by writing the desired mode (0 or 1) to /sys/class/powercap/intel-rapl/enabled
Signed-off-by: Suchit Karunakaran <suchitkarunakaran@gmail.com>
---
tools/power/cpupower/lib/powercap.c | 22 ++++++++++++++++++----
1 file changed, 18 insertions(+), 4 deletions(-)
diff --git a/tools/power/cpupower/lib/powercap.c b/tools/power/cpupower/lib/powercap.c
index 94a0c69e55ef..7947b9809239 100644
--- a/tools/power/cpupower/lib/powercap.c
+++ b/tools/power/cpupower/lib/powercap.c
@@ -70,6 +70,22 @@ static int sysfs_get_enabled(char *path, int *mode)
return ret;
}
+static int sysfs_set_enabled(const char *path, int mode)
+{
+ int fd;
+ char buf[2] = { mode ? '1' : '0', '\n' };
+ ssize_t ret;
+
+ fd = open(path, O_WRONLY);
+ if (fd == -1)
+ return -1;
+
+ ret = write(fd, buf, sizeof(buf));
+ close(fd);
+
+ return ret == sizeof(buf) ? 0 : -1;
+}
+
int powercap_get_enabled(int *mode)
{
char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP "/intel-rapl/enabled";
@@ -77,12 +93,10 @@ int powercap_get_enabled(int *mode)
return sysfs_get_enabled(path, mode);
}
-/*
- * TODO: implement function. Returns dummy 0 for now.
- */
int powercap_set_enabled(int mode)
{
- return 0;
+ char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP "/intel-rapl/enabled";
+ return sysfs_set_enabled(path, mode);
}
/*
--
2.49.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH] tools/powercap: Implement powercap_set_enabled()
2025-05-10 18:47 [PATCH] tools/powercap: Implement powercap_set_enabled() Suchit Karunakaran
@ 2025-05-13 22:03 ` Shuah Khan
2025-05-14 1:20 ` Suchit K
0 siblings, 1 reply; 4+ messages in thread
From: Shuah Khan @ 2025-05-13 22:03 UTC (permalink / raw)
To: Suchit Karunakaran, trenn, shuah, jwyatt, jkacur, linux-pm
Cc: linux-kernel-mentees, linux-kernel, Shuah Khan
On 5/10/25 12:47, Suchit Karunakaran wrote:
> The powercap_set_enabled() function previously returned a dummy value
> and was marked with a TODO comment. This patch implements the function
> by writing the desired mode (0 or 1) to /sys/class/powercap/intel-rapl/enabled
The short summary should say cpupower: Implement powercap_set_enabled()
>
> Signed-off-by: Suchit Karunakaran <suchitkarunakaran@gmail.com>
> ---
> tools/power/cpupower/lib/powercap.c | 22 ++++++++++++++++++----
> 1 file changed, 18 insertions(+), 4 deletions(-)
>
> diff --git a/tools/power/cpupower/lib/powercap.c b/tools/power/cpupower/lib/powercap.c
> index 94a0c69e55ef..7947b9809239 100644
> --- a/tools/power/cpupower/lib/powercap.c
> +++ b/tools/power/cpupower/lib/powercap.c
> @@ -70,6 +70,22 @@ static int sysfs_get_enabled(char *path, int *mode)
> return ret;
> }
>
> +static int sysfs_set_enabled(const char *path, int mode)
> +{
> + int fd;
> + char buf[2] = { mode ? '1' : '0', '\n' };
> + ssize_t ret;
> +
> + fd = open(path, O_WRONLY);
> + if (fd == -1)
> + return -1;
> +
> + ret = write(fd, buf, sizeof(buf));
> + close(fd);
> +
> + return ret == sizeof(buf) ? 0 : -1;
> +}
> +
> int powercap_get_enabled(int *mode)
> {
> char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP "/intel-rapl/enabled";
> @@ -77,12 +93,10 @@ int powercap_get_enabled(int *mode)
> return sysfs_get_enabled(path, mode);
> }
>
> -/*
> - * TODO: implement function. Returns dummy 0 for now.
> - */
> int powercap_set_enabled(int mode)
> {
> - return 0;
> + char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP "/intel-rapl/enabled";
> + return sysfs_set_enabled(path, mode);
Did you compile this?
thanks,
-- Shuah
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] tools/powercap: Implement powercap_set_enabled()
2025-05-13 22:03 ` Shuah Khan
@ 2025-05-14 1:20 ` Suchit K
2025-05-14 19:53 ` Shuah Khan
0 siblings, 1 reply; 4+ messages in thread
From: Suchit K @ 2025-05-14 1:20 UTC (permalink / raw)
To: Shuah Khan
Cc: trenn, shuah, jwyatt, jkacur, linux-pm, linux-kernel-mentees,
linux-kernel
Thanks for the suggestion, Shuah. And I did compile the kernel after
making the changes.
On Wed, 14 May 2025 at 03:33, Shuah Khan <skhan@linuxfoundation.org> wrote:
>
> On 5/10/25 12:47, Suchit Karunakaran wrote:
> > The powercap_set_enabled() function previously returned a dummy value
> > and was marked with a TODO comment. This patch implements the function
> > by writing the desired mode (0 or 1) to /sys/class/powercap/intel-rapl/enabled
>
> The short summary should say cpupower: Implement powercap_set_enabled()
> >
> > Signed-off-by: Suchit Karunakaran <suchitkarunakaran@gmail.com>
> > ---
> > tools/power/cpupower/lib/powercap.c | 22 ++++++++++++++++++----
> > 1 file changed, 18 insertions(+), 4 deletions(-)
> >
> > diff --git a/tools/power/cpupower/lib/powercap.c b/tools/power/cpupower/lib/powercap.c
> > index 94a0c69e55ef..7947b9809239 100644
> > --- a/tools/power/cpupower/lib/powercap.c
> > +++ b/tools/power/cpupower/lib/powercap.c
> > @@ -70,6 +70,22 @@ static int sysfs_get_enabled(char *path, int *mode)
> > return ret;
> > }
> >
> > +static int sysfs_set_enabled(const char *path, int mode)
> > +{
> > + int fd;
> > + char buf[2] = { mode ? '1' : '0', '\n' };
> > + ssize_t ret;
> > +
> > + fd = open(path, O_WRONLY);
> > + if (fd == -1)
> > + return -1;
> > +
> > + ret = write(fd, buf, sizeof(buf));
> > + close(fd);
> > +
> > + return ret == sizeof(buf) ? 0 : -1;
> > +}
> > +
> > int powercap_get_enabled(int *mode)
> > {
> > char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP "/intel-rapl/enabled";
> > @@ -77,12 +93,10 @@ int powercap_get_enabled(int *mode)
> > return sysfs_get_enabled(path, mode);
> > }
> >
> > -/*
> > - * TODO: implement function. Returns dummy 0 for now.
> > - */
> > int powercap_set_enabled(int mode)
> > {
> > - return 0;
> > + char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP "/intel-rapl/enabled";
> > + return sysfs_set_enabled(path, mode);
>
> Did you compile this?
>
> thanks,
> -- Shuah
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] tools/powercap: Implement powercap_set_enabled()
2025-05-14 1:20 ` Suchit K
@ 2025-05-14 19:53 ` Shuah Khan
0 siblings, 0 replies; 4+ messages in thread
From: Shuah Khan @ 2025-05-14 19:53 UTC (permalink / raw)
To: Suchit K
Cc: trenn, shuah, jwyatt, jkacur, linux-pm, linux-kernel-mentees,
linux-kernel, Shuah Khan
On 5/13/25 19:20, Suchit K wrote:
> Thanks for the suggestion, Shuah. And I did compile the kernel after
> making the changes.
>
>
Please don't top post in kernel patch responses.
> On Wed, 14 May 2025 at 03:33, Shuah Khan <skhan@linuxfoundation.org> wrote:
>>
>> On 5/10/25 12:47, Suchit Karunakaran wrote:
>>> The powercap_set_enabled() function previously returned a dummy value
>>> and was marked with a TODO comment. This patch implements the function
>>> by writing the desired mode (0 or 1) to /sys/class/powercap/intel-rapl/enabled
>>
>> The short summary should say cpupower: Implement powercap_set_enabled()
I am not clear on how this can be used. Can you elaborate on the use-case
for the set?
Send me v2 fixing the change log.
>>>
>>> Signed-off-by: Suchit Karunakaran <suchitkarunakaran@gmail.com>
>>> ---
>>> tools/power/cpupower/lib/powercap.c | 22 ++++++++++++++++++----
>>> 1 file changed, 18 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/tools/power/cpupower/lib/powercap.c b/tools/power/cpupower/lib/powercap.c
>>> index 94a0c69e55ef..7947b9809239 100644
>>> --- a/tools/power/cpupower/lib/powercap.c
>>> +++ b/tools/power/cpupower/lib/powercap.c
>>> @@ -70,6 +70,22 @@ static int sysfs_get_enabled(char *path, int *mode)
>>> return ret;
>>> }
>>>
>>> +static int sysfs_set_enabled(const char *path, int mode)
>>> +{
>>> + int fd;
>>> + char buf[2] = { mode ? '1' : '0', '\n' };
>>> + ssize_t ret;
>>> +
>>> + fd = open(path, O_WRONLY);
>>> + if (fd == -1)
>>> + return -1;
>>> +
>>> + ret = write(fd, buf, sizeof(buf));
>>> + close(fd);
>>> +
>>> + return ret == sizeof(buf) ? 0 : -1;
>>> +}
>>> +
>>> int powercap_get_enabled(int *mode)
>>> {
>>> char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP "/intel-rapl/enabled";
>>> @@ -77,12 +93,10 @@ int powercap_get_enabled(int *mode)
>>> return sysfs_get_enabled(path, mode);
>>> }
>>>
>>> -/*
>>> - * TODO: implement function. Returns dummy 0 for now.
>>> - */
>>> int powercap_set_enabled(int mode)
>>> {
>>> - return 0;
>>> + char path[SYSFS_PATH_MAX] = PATH_TO_POWERCAP "/intel-rapl/enabled";
>>> + return sysfs_set_enabled(path, mode);
>>
>> Did you compile this?
>>
>> thanks,
>> -- Shuah
^ permalink raw reply [flat|nested] 4+ messages in thread
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2025-05-10 18:47 [PATCH] tools/powercap: Implement powercap_set_enabled() Suchit Karunakaran
2025-05-13 22:03 ` Shuah Khan
2025-05-14 1:20 ` Suchit K
2025-05-14 19:53 ` Shuah Khan
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