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Date: Thu, 28 Feb 2019 15:22:00 +0530
From: Gautham R Shenoy <ego@...ux.vnet.ibm.com>
To: Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com>
Cc: Daniel Axtens <dja@...ens.net>, mpe@...erman.id.au,
linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
ego@...ux.vnet.ibm.com
Subject: Re: [PATCH] powernv: powercap: Add hard minimum powercap
Hi Shilpa,
On Thu, Feb 28, 2019 at 11:25:25AM +0530, Shilpasri G Bhat wrote:
> Hi,
>
> On 02/28/2019 10:14 AM, Daniel Axtens wrote:
> > Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com> writes:
> >
> >> In POWER9, OCC(On-Chip-Controller) provides for hard and soft system
> >> powercapping range. The hard powercap range is guaranteed while soft
> >> powercap may or may not be asserted due to various power-thermal
> >> reasons based on system configuration and workloads. This patch adds
> >> a sysfs file to export the hard minimum powercap limit to allow the
> >> user to set the appropriate powercap value that can be managed by the
> >> system.
> >
> > Maybe it's common terminology and I'm just not aware of it, but what do
> > you mean by "asserted"? It doesn't appear elsewhere in the documentation
> > you're patching, and it's not a use of assert that I'm familiar with...
> >
> > Regards,
> > Daniel
> >
>
> I meant to say powercap will not be assured in the soft powercap range, i.e,
> system may or may not be throttled of CPU frequency to remain within the powercap.
>
> I can reword the document and commit message.
I agree with Daniel. How about replacing "asserted" with "enforced by
the OCC"?
>
> Thanks and Regards,
> Shilpa
--
Thanks and Regards
gautham.
>
> >>
> >> Signed-off-by: Shilpasri G Bhat <shilpa.bhat@...ux.vnet.ibm.com>
> >> ---
> >> .../ABI/testing/sysfs-firmware-opal-powercap | 10 ++++
> >> arch/powerpc/platforms/powernv/opal-powercap.c | 66 +++++++++-------------
> >> 2 files changed, 37 insertions(+), 39 deletions(-)
> >>
> >> diff --git a/Documentation/ABI/testing/sysfs-firmware-opal-powercap b/Documentation/ABI/testing/sysfs-firmware-opal-powercap
> >> index c9b66ec..65db4c1 100644
> >> --- a/Documentation/ABI/testing/sysfs-firmware-opal-powercap
> >> +++ b/Documentation/ABI/testing/sysfs-firmware-opal-powercap
> >> @@ -29,3 +29,13 @@ Description: System powercap directory and attributes applicable for
> >> creates a request for setting a new-powercap. The
> >> powercap requested must be between powercap-min
> >> and powercap-max.
> >> +
> >> +What: /sys/firmware/opal/powercap/system-powercap/powercap-hard-min
> >> +Date: Feb 2019
> >> +Contact: Linux for PowerPC mailing list <linuxppc-dev@...abs.org>
> >> +Description: Hard minimum powercap
> >> +
> >> + This file provides the hard minimum powercap limit in
> >> + Watts. The powercap value above hard minimum is always
> >> + guaranteed to be asserted and the powercap value below
> >> + the hard minimum limit may or may not be guaranteed.
> >> diff --git a/arch/powerpc/platforms/powernv/opal-powercap.c b/arch/powerpc/platforms/powernv/opal-powercap.c
> >> index d90ee4f..38408e7 100644
> >> --- a/arch/powerpc/platforms/powernv/opal-powercap.c
> >> +++ b/arch/powerpc/platforms/powernv/opal-powercap.c
> >> @@ -139,10 +139,24 @@ static void powercap_add_attr(int handle, const char *name,
> >> attr->handle = handle;
> >> sysfs_attr_init(&attr->attr.attr);
> >> attr->attr.attr.name = name;
> >> - attr->attr.attr.mode = 0444;
> >> +
> >> + if (!strncmp(name, "powercap-current", strlen(name))) {
> >> + attr->attr.attr.mode = 0664;
> >> + attr->attr.store = powercap_store;
> >> + } else {
> >> + attr->attr.attr.mode = 0444;
> >> + }
> >> +
> >> attr->attr.show = powercap_show;
> >> }
> >>
> >> +static const char * const powercap_strs[] = {
> >> + "powercap-max",
> >> + "powercap-min",
> >> + "powercap-current",
> >> + "powercap-hard-min",
> >> +};
> >> +
> >> void __init opal_powercap_init(void)
> >> {
> >> struct device_node *powercap, *node;
> >> @@ -167,60 +181,34 @@ void __init opal_powercap_init(void)
> >>
> >> i = 0;
> >> for_each_child_of_node(powercap, node) {
> >> - u32 cur, min, max;
> >> - int j = 0;
> >> - bool has_cur = false, has_min = false, has_max = false;
> >> + u32 id;
> >> + int j, count = 0;
> >>
> >> - if (!of_property_read_u32(node, "powercap-min", &min)) {
> >> - j++;
> >> - has_min = true;
> >> - }
> >> -
> >> - if (!of_property_read_u32(node, "powercap-max", &max)) {
> >> - j++;
> >> - has_max = true;
> >> - }
> >> + for (j = 0; j < ARRAY_SIZE(powercap_strs); j++)
> >> + if (!of_property_read_u32(node, powercap_strs[j], &id))
> >> + count++;
> >>
> >> - if (!of_property_read_u32(node, "powercap-current", &cur)) {
> >> - j++;
> >> - has_cur = true;
> >> - }
> >> -
> >> - pcaps[i].pattrs = kcalloc(j, sizeof(struct powercap_attr),
> >> + pcaps[i].pattrs = kcalloc(count, sizeof(struct powercap_attr),
> >> GFP_KERNEL);
> >> if (!pcaps[i].pattrs)
> >> goto out_pcaps_pattrs;
> >>
> >> - pcaps[i].pg.attrs = kcalloc(j + 1, sizeof(struct attribute *),
> >> + pcaps[i].pg.attrs = kcalloc(count + 1,
> >> + sizeof(struct attribute *),
> >> GFP_KERNEL);
> >> if (!pcaps[i].pg.attrs) {
> >> kfree(pcaps[i].pattrs);
> >> goto out_pcaps_pattrs;
> >> }
> >>
> >> - j = 0;
> >> pcaps[i].pg.name = kasprintf(GFP_KERNEL, "%pOFn", node);
> >> - if (has_min) {
> >> - powercap_add_attr(min, "powercap-min",
> >> - &pcaps[i].pattrs[j]);
> >> - pcaps[i].pg.attrs[j] = &pcaps[i].pattrs[j].attr.attr;
> >> - j++;
> >> - }
> >> -
> >> - if (has_max) {
> >> - powercap_add_attr(max, "powercap-max",
> >> - &pcaps[i].pattrs[j]);
> >> - pcaps[i].pg.attrs[j] = &pcaps[i].pattrs[j].attr.attr;
> >> - j++;
> >> - }
> >> + for (j = 0; j < ARRAY_SIZE(powercap_strs); j++) {
> >> + if (of_property_read_u32(node, powercap_strs[j], &id))
> >> + continue;
> >>
> >> - if (has_cur) {
> >> - powercap_add_attr(cur, "powercap-current",
> >> + powercap_add_attr(id, powercap_strs[j],
> >> &pcaps[i].pattrs[j]);
> >> - pcaps[i].pattrs[j].attr.attr.mode |= 0220;
> >> - pcaps[i].pattrs[j].attr.store = powercap_store;
> >> pcaps[i].pg.attrs[j] = &pcaps[i].pattrs[j].attr.attr;
> >> - j++;
> >> }
> >>
> >> if (sysfs_create_group(powercap_kobj, &pcaps[i].pg)) {
> >> --
> >> 1.8.3.1
> >
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