resctrl_arch_rmid_read() returns a value in chunks, as read from the
hardware. This needs scaling to bytes by mon_scale, as provided by
the architecture code.
Now that resctrl_arch_rmid_read() performs the overflow and corrections
itself, it may as well return a value in bytes directly. This allows
the accesses to the architecture specific 'hw' structure to be removed.
Move the mon_scale conversion into resctrl_arch_rmid_read().
mbm_bw_count() is updated to calculate bandwidth from bytes.
Signed-off-by: James Morse <[email protected]>
---
arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 6 ++----
arch/x86/kernel/cpu/resctrl/internal.h | 4 ++--
arch/x86/kernel/cpu/resctrl/monitor.c | 22 +++++++++-------------
include/linux/resctrl.h | 2 +-
4 files changed, 14 insertions(+), 20 deletions(-)
diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
index d3f7eb2ac14b..03fc91d8bc9f 100644
--- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
+++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
@@ -549,7 +549,6 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
int rdtgroup_mondata_show(struct seq_file *m, void *arg)
{
struct kernfs_open_file *of = m->private;
- struct rdt_hw_resource *hw_res;
u32 resid, evtid, domid;
struct rdtgroup *rdtgrp;
struct rdt_resource *r;
@@ -569,8 +568,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
domid = md.u.domid;
evtid = md.u.evtid;
- hw_res = &rdt_resources_all[resid];
- r = &hw_res->r_resctrl;
+ r = &rdt_resources_all[resid].r_resctrl;
d = rdt_find_domain(r, domid, NULL);
if (IS_ERR_OR_NULL(d)) {
ret = -ENOENT;
@@ -584,7 +582,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
else if (rr.err == -EINVAL)
seq_puts(m, "Unavailable\n");
else
- seq_printf(m, "%llu\n", rr.val * hw_res->mon_scale);
+ seq_printf(m, "%llu\n", rr.val);
out:
rdtgroup_kn_unlock(of->kn);
diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
index e26a4d67e204..d6ce6ce91885 100644
--- a/arch/x86/kernel/cpu/resctrl/internal.h
+++ b/arch/x86/kernel/cpu/resctrl/internal.h
@@ -279,13 +279,13 @@ struct rftype {
/**
* struct mbm_state - status for each MBM counter in each domain
- * @prev_bw_chunks: Previous chunks value read when for bandwidth calculation
+ * @prev_bw_bytes: Previous bytes value read when for bandwidth calculation
* @prev_bw: The most recent bandwidth in MBps
* @delta_bw: Difference between the current and previous bandwidth
* @delta_comp: Indicates whether to compute the delta_bw
*/
struct mbm_state {
- u64 prev_bw_chunks;
+ u64 prev_bw_bytes;
u32 prev_bw;
u32 delta_bw;
bool delta_comp;
diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
index 3a6555f49720..437e7db77f93 100644
--- a/arch/x86/kernel/cpu/resctrl/monitor.c
+++ b/arch/x86/kernel/cpu/resctrl/monitor.c
@@ -186,7 +186,7 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);
struct arch_mbm_state *am;
- u64 msr_val;
+ u64 msr_val, chunks;
if (!cpumask_test_cpu(smp_processor_id(), &d->cpu_mask))
return -EINVAL;
@@ -211,10 +211,11 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
if (am) {
am->chunks += mbm_overflow_count(am->prev_msr, msr_val,
hw_res->mbm_width);
- *val = get_corrected_mbm_count(rmid, am->chunks);
+ chunks = get_corrected_mbm_count(rmid, am->chunks);
+ *val = chunks * hw_res->mon_scale;
am->prev_msr = msr_val;
} else {
- *val = msr_val;
+ *val = msr_val * hw_res->mon_scale;
}
return 0;
@@ -229,7 +230,6 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
void __check_limbo(struct rdt_domain *d, bool force_free)
{
struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
- struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
struct rmid_entry *entry;
u32 crmid = 1, nrmid;
bool rmid_dirty;
@@ -252,7 +252,6 @@ void __check_limbo(struct rdt_domain *d, bool force_free)
QOS_L3_OCCUP_EVENT_ID, &val)) {
rmid_dirty = true;
} else {
- val *= hw_res->mon_scale;
rmid_dirty = (val >= resctrl_rmid_realloc_threshold);
}
@@ -296,7 +295,6 @@ int alloc_rmid(void)
static void add_rmid_to_limbo(struct rmid_entry *entry)
{
struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
- struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
struct rdt_domain *d;
int cpu, err;
u64 val = 0;
@@ -308,7 +306,6 @@ static void add_rmid_to_limbo(struct rmid_entry *entry)
err = resctrl_arch_rmid_read(r, d, entry->rmid,
QOS_L3_OCCUP_EVENT_ID,
&val);
- val *= hw_res->mon_scale;
if (err || val <= resctrl_rmid_realloc_threshold)
continue;
}
@@ -400,15 +397,14 @@ static u64 __mon_event_count(u32 rmid, struct rmid_read *rr)
*/
static void mbm_bw_count(u32 rmid, struct rmid_read *rr)
{
- struct rdt_hw_resource *hw_res = resctrl_to_arch_res(rr->r);
struct mbm_state *m = &rr->d->mbm_local[rmid];
- u64 cur_bw, chunks, cur_chunks;
+ u64 cur_bw, bytes, cur_bytes;
- cur_chunks = rr->val;
- chunks = cur_chunks - m->prev_bw_chunks;
- m->prev_bw_chunks = cur_chunks;
+ cur_bytes = rr->val;
+ bytes = cur_bytes - m->prev_bw_bytes;
+ m->prev_bw_bytes = cur_bytes;
- cur_bw = (chunks * hw_res->mon_scale) >> 20;
+ cur_bw = bytes >> 20;
if (m->delta_comp)
m->delta_bw = abs(cur_bw - m->prev_bw);
diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h
index fc00bf1bafa7..4e0a7a549280 100644
--- a/include/linux/resctrl.h
+++ b/include/linux/resctrl.h
@@ -227,7 +227,7 @@ void resctrl_offline_domain(struct rdt_resource *r, struct rdt_domain *d);
* @d: domain that the counter should be read from.
* @rmid: rmid of the counter to read.
* @eventid: eventid to read, e.g. L3 occupancy.
- * @val: result of the counter read in chunks.
+ * @val: result of the counter read in bytes.
*
* Return:
* 0 on success, or -EIO, -EINVAL etc on error.
--
2.30.2
On Thu, Feb 17, 2022 at 06:21:10PM +0000, James Morse wrote:
> resctrl_arch_rmid_read() returns a value in chunks, as read from the
> hardware. This needs scaling to bytes by mon_scale, as provided by
> the architecture code.
>
> Now that resctrl_arch_rmid_read() performs the overflow and corrections
> itself, it may as well return a value in bytes directly. This allows
> the accesses to the architecture specific 'hw' structure to be removed.
>
> Move the mon_scale conversion into resctrl_arch_rmid_read().
> mbm_bw_count() is updated to calculate bandwidth from bytes.
>
> Signed-off-by: James Morse <[email protected]>
> ---
> arch/x86/kernel/cpu/resctrl/ctrlmondata.c | 6 ++----
> arch/x86/kernel/cpu/resctrl/internal.h | 4 ++--
> arch/x86/kernel/cpu/resctrl/monitor.c | 22 +++++++++-------------
> include/linux/resctrl.h | 2 +-
> 4 files changed, 14 insertions(+), 20 deletions(-)
>
> diff --git a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> index d3f7eb2ac14b..03fc91d8bc9f 100644
> --- a/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> +++ b/arch/x86/kernel/cpu/resctrl/ctrlmondata.c
> @@ -549,7 +549,6 @@ void mon_event_read(struct rmid_read *rr, struct rdt_resource *r,
> int rdtgroup_mondata_show(struct seq_file *m, void *arg)
> {
> struct kernfs_open_file *of = m->private;
> - struct rdt_hw_resource *hw_res;
> u32 resid, evtid, domid;
> struct rdtgroup *rdtgrp;
> struct rdt_resource *r;
> @@ -569,8 +568,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
> domid = md.u.domid;
> evtid = md.u.evtid;
>
> - hw_res = &rdt_resources_all[resid];
> - r = &hw_res->r_resctrl;
> + r = &rdt_resources_all[resid].r_resctrl;
> d = rdt_find_domain(r, domid, NULL);
> if (IS_ERR_OR_NULL(d)) {
> ret = -ENOENT;
> @@ -584,7 +582,7 @@ int rdtgroup_mondata_show(struct seq_file *m, void *arg)
> else if (rr.err == -EINVAL)
> seq_puts(m, "Unavailable\n");
> else
> - seq_printf(m, "%llu\n", rr.val * hw_res->mon_scale);
> + seq_printf(m, "%llu\n", rr.val);
>
> out:
> rdtgroup_kn_unlock(of->kn);
> diff --git a/arch/x86/kernel/cpu/resctrl/internal.h b/arch/x86/kernel/cpu/resctrl/internal.h
> index e26a4d67e204..d6ce6ce91885 100644
> --- a/arch/x86/kernel/cpu/resctrl/internal.h
> +++ b/arch/x86/kernel/cpu/resctrl/internal.h
> @@ -279,13 +279,13 @@ struct rftype {
>
> /**
> * struct mbm_state - status for each MBM counter in each domain
> - * @prev_bw_chunks: Previous chunks value read when for bandwidth calculation
> + * @prev_bw_bytes: Previous bytes value read when for bandwidth calculation
> * @prev_bw: The most recent bandwidth in MBps
> * @delta_bw: Difference between the current and previous bandwidth
> * @delta_comp: Indicates whether to compute the delta_bw
> */
> struct mbm_state {
> - u64 prev_bw_chunks;
> + u64 prev_bw_bytes;
> u32 prev_bw;
> u32 delta_bw;
> bool delta_comp;
> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
> index 3a6555f49720..437e7db77f93 100644
> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
> @@ -186,7 +186,7 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
> struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
> struct rdt_hw_domain *hw_dom = resctrl_to_arch_dom(d);
> struct arch_mbm_state *am;
> - u64 msr_val;
> + u64 msr_val, chunks;
>
> if (!cpumask_test_cpu(smp_processor_id(), &d->cpu_mask))
> return -EINVAL;
> @@ -211,10 +211,11 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
> if (am) {
> am->chunks += mbm_overflow_count(am->prev_msr, msr_val,
> hw_res->mbm_width);
> - *val = get_corrected_mbm_count(rmid, am->chunks);
> + chunks = get_corrected_mbm_count(rmid, am->chunks);
> + *val = chunks * hw_res->mon_scale;
This can be moved out of the if/else if you make the following change:
> am->prev_msr = msr_val;
> } else {
> - *val = msr_val;
> + *val = msr_val * hw_res->mon_scale;
chunks = msr_val;
> }
>
> return 0;
> @@ -229,7 +230,6 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
> void __check_limbo(struct rdt_domain *d, bool force_free)
> {
> struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
> - struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
> struct rmid_entry *entry;
> u32 crmid = 1, nrmid;
> bool rmid_dirty;
> @@ -252,7 +252,6 @@ void __check_limbo(struct rdt_domain *d, bool force_free)
> QOS_L3_OCCUP_EVENT_ID, &val)) {
> rmid_dirty = true;
> } else {
> - val *= hw_res->mon_scale;
> rmid_dirty = (val >= resctrl_rmid_realloc_threshold);
> }
>
> @@ -296,7 +295,6 @@ int alloc_rmid(void)
> static void add_rmid_to_limbo(struct rmid_entry *entry)
> {
> struct rdt_resource *r = &rdt_resources_all[RDT_RESOURCE_L3].r_resctrl;
> - struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
> struct rdt_domain *d;
> int cpu, err;
> u64 val = 0;
> @@ -308,7 +306,6 @@ static void add_rmid_to_limbo(struct rmid_entry *entry)
> err = resctrl_arch_rmid_read(r, d, entry->rmid,
> QOS_L3_OCCUP_EVENT_ID,
> &val);
> - val *= hw_res->mon_scale;
> if (err || val <= resctrl_rmid_realloc_threshold)
> continue;
> }
> @@ -400,15 +397,14 @@ static u64 __mon_event_count(u32 rmid, struct rmid_read *rr)
> */
> static void mbm_bw_count(u32 rmid, struct rmid_read *rr)
> {
> - struct rdt_hw_resource *hw_res = resctrl_to_arch_res(rr->r);
> struct mbm_state *m = &rr->d->mbm_local[rmid];
> - u64 cur_bw, chunks, cur_chunks;
> + u64 cur_bw, bytes, cur_bytes;
>
> - cur_chunks = rr->val;
> - chunks = cur_chunks - m->prev_bw_chunks;
> - m->prev_bw_chunks = cur_chunks;
> + cur_bytes = rr->val;
> + bytes = cur_bytes - m->prev_bw_bytes;
> + m->prev_bw_bytes = cur_bytes;
>
> - cur_bw = (chunks * hw_res->mon_scale) >> 20;
> + cur_bw = bytes >> 20;
'bytes / SZ_1M' would be more readable and any decent compiler should
optimize a power of 2 divide. But maybe that's a separate change as
there are other cases of bytes to MB.
Rob
Hi Rob,
On 3/23/22 21:17, Rob Herring wrote:
> On Thu, Feb 17, 2022 at 06:21:10PM +0000, James Morse wrote:
>> resctrl_arch_rmid_read() returns a value in chunks, as read from the
>> hardware. This needs scaling to bytes by mon_scale, as provided by
>> the architecture code.
>>
>> Now that resctrl_arch_rmid_read() performs the overflow and corrections
>> itself, it may as well return a value in bytes directly. This allows
>> the accesses to the architecture specific 'hw' structure to be removed.
>>
>> Move the mon_scale conversion into resctrl_arch_rmid_read().
>> mbm_bw_count() is updated to calculate bandwidth from bytes.
>> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
>> index 3a6555f49720..437e7db77f93 100644
>> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
>> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
>> @@ -211,10 +211,11 @@ int resctrl_arch_rmid_read(struct rdt_resource *r, struct rdt_domain *d,
>> if (am) {
>> am->chunks += mbm_overflow_count(am->prev_msr, msr_val,
>> hw_res->mbm_width);
>> - *val = get_corrected_mbm_count(rmid, am->chunks);
>> + chunks = get_corrected_mbm_count(rmid, am->chunks);
>> + *val = chunks * hw_res->mon_scale;
>
> This can be moved out of the if/else if you make the following change:
>
>> am->prev_msr = msr_val;
>> } else {
>> - *val = msr_val;
>> + *val = msr_val * hw_res->mon_scale;
>
> chunks = msr_val;
>
>> }
Sure, I guess it makes sense to only set *val in one place.
>>
>> return 0;
>> @@ -400,15 +397,14 @@ static u64 __mon_event_count(u32 rmid, struct rmid_read *rr)
>> */
>> static void mbm_bw_count(u32 rmid, struct rmid_read *rr)
>> {
>> - struct rdt_hw_resource *hw_res = resctrl_to_arch_res(rr->r);
>> struct mbm_state *m = &rr->d->mbm_local[rmid];
>> - u64 cur_bw, chunks, cur_chunks;
>> + u64 cur_bw, bytes, cur_bytes;
>>
>> - cur_chunks = rr->val;
>> - chunks = cur_chunks - m->prev_bw_chunks;
>> - m->prev_bw_chunks = cur_chunks;
>> + cur_bytes = rr->val;
>> + bytes = cur_bytes - m->prev_bw_bytes;
>> + m->prev_bw_bytes = cur_bytes;
>>
>> - cur_bw = (chunks * hw_res->mon_scale) >> 20;
>> + cur_bw = bytes >> 20;
>
> 'bytes / SZ_1M' would be more readable and any decent compiler should
> optimize a power of 2 divide. But maybe that's a separate change as
> there are other cases of bytes to MB.
I agree its more readable. As I've touched this one, I'll change it.
Thanks,
James