| Message ID | 20170420144316.15632-9-juri.lelli@arm.com |
|---|---|
| State | New |
| Headers | show |
| Series | Fix issues and factorize arm/arm64 capacity information code | expand |
On Thu, Apr 20, 2017 at 03:43:16PM +0100, Juri Lelli wrote: > Now that some functions that deal with arch topology information live > under drivers, there is a clash of naming that might create confusion. > > Tidy things up by creating a drivers namespace for interfaces used by > arch code; achieve this by prepending a 'atd_' (arch topology driver) > prefix to driver interfaces. No one knows, nor will they ever remember, what "atd_" means :( Naming is hard, I know, here's my suggestion: > diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h > index 4edae9fe8cdd..e25458d7ee9a 100644 > --- a/include/linux/arch_topology.h > +++ b/include/linux/arch_topology.h > @@ -4,14 +4,14 @@ > #ifndef _LINUX_ARCH_TOPOLOGY_H_ > #define _LINUX_ARCH_TOPOLOGY_H_ > > -void normalize_cpu_capacity(void); > +void atd_normalize_cpu_capacity(void); arch_cpu_normalize_capacity(); or cpu_normalize_capacity(); Why do you care if this is "arch" or not, of course it's arch-specific in a way, right? > > struct device_node; > -int parse_cpu_capacity(struct device_node *cpu_node, int cpu); > +int atd_parse_cpu_capacity(struct device_node *cpu_node, int cpu); cpu_parse_capacity(); > struct sched_domain; > -unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu); > +unsigned long atd_scale_cpu_capacity(struct sched_domain *sd, int cpu); cpu_scale_capacity(); > -void set_capacity_scale(unsigned int cpu, unsigned long capacity); > +void atd_set_capacity_scale(unsigned int cpu, unsigned long capacity); wait, where did the cpu go? This doesn't make much sense, these are all "capacity" issues, right? If so, then these should be: capacity_normalize_cpu() capacity_parse_cpu() capacity_scale_cpu() capacity_set_scale() But this is all really topology stuff, right? Why use "capacity" at all: topology_normalize_cpu() topology_parse_cpu() topology_scale_cpu() topology_set_scale() ? It's always best to put the "subsystem" name first, we have a bad history of getting this wrong in the past by putting the verb first, not the noun. thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Fri, May 26, 2017 at 11:10:32AM +0100, Juri Lelli wrote: > Hi, > > On 25/05/17 15:18, Greg KH wrote: > > On Thu, Apr 20, 2017 at 03:43:16PM +0100, Juri Lelli wrote: > > > Now that some functions that deal with arch topology information live > > > under drivers, there is a clash of naming that might create confusion. > > > > > > Tidy things up by creating a drivers namespace for interfaces used by > > > arch code; achieve this by prepending a 'atd_' (arch topology driver) > > > prefix to driver interfaces. > > > > No one knows, nor will they ever remember, what "atd_" means :( > > > > Naming is hard, I know, here's my suggestion: > > > > > diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h > > > index 4edae9fe8cdd..e25458d7ee9a 100644 > > > --- a/include/linux/arch_topology.h > > > +++ b/include/linux/arch_topology.h > > > @@ -4,14 +4,14 @@ > > > #ifndef _LINUX_ARCH_TOPOLOGY_H_ > > > #define _LINUX_ARCH_TOPOLOGY_H_ > > > > > > -void normalize_cpu_capacity(void); > > > +void atd_normalize_cpu_capacity(void); > > > > arch_cpu_normalize_capacity(); > > or > > cpu_normalize_capacity(); > > > > Why do you care if this is "arch" or not, of course it's arch-specific > > in a way, right? > > > > > > > > struct device_node; > > > -int parse_cpu_capacity(struct device_node *cpu_node, int cpu); > > > +int atd_parse_cpu_capacity(struct device_node *cpu_node, int cpu); > > > > cpu_parse_capacity(); > > > > > struct sched_domain; > > > -unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu); > > > +unsigned long atd_scale_cpu_capacity(struct sched_domain *sd, int cpu); > > > > cpu_scale_capacity(); > > > > > -void set_capacity_scale(unsigned int cpu, unsigned long capacity); > > > +void atd_set_capacity_scale(unsigned int cpu, unsigned long capacity); > > > > wait, where did the cpu go? This doesn't make much sense, these are all > > "capacity" issues, right? If so, then these should be: > > capacity_normalize_cpu() > > capacity_parse_cpu() > > capacity_scale_cpu() > > capacity_set_scale() > > > > But this is all really topology stuff, right? Why use "capacity" at > > all: > > topology_normalize_cpu() > > topology_parse_cpu() > > topology_scale_cpu() > > topology_set_scale() > > ? > > > > It's always best to put the "subsystem" name first, we have a bad > > history of getting this wrong in the past by putting the verb first, not > > the noun. > > > > topology_ works for me. However, I'd keep "capacity" in the names, as we > might need to topology_normalize_cpu_somethingelse() (etc.) in the > future? Worry about the future, in the future. Change the names then, _IF_ it becomes an issue. Try to be short and simple please. > Updated patch follows. I kept Catalin and Russell's acks as I only > renamed the functions, please shout if that's not OK. > > Greg, if you are fine with this approach, do you still want a complete > v5 of the set or can you pick this up? Am I the one who is supposed to take all of these arm-specific patches? If so, that's fine, but I need to have acks from the arm maintainers... Oh, and drop "capacity" please :) thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, May 29, 2017 at 11:20:24AM +0200, Dietmar Eggemann wrote: > Hi Greg, > > On 05/26/2017 08:36 PM, Greg KH wrote: > > On Fri, May 26, 2017 at 11:10:32AM +0100, Juri Lelli wrote: > > > Hi, > > > > > > On 25/05/17 15:18, Greg KH wrote: > > > > On Thu, Apr 20, 2017 at 03:43:16PM +0100, Juri Lelli wrote: > > [...] > > > > > But this is all really topology stuff, right? Why use "capacity" at > > > > all: > > > > topology_normalize_cpu() > > > > topology_parse_cpu() > > > > topology_scale_cpu() > > > > topology_set_scale() > > > > ? > > > > > > > > It's always best to put the "subsystem" name first, we have a bad > > > > history of getting this wrong in the past by putting the verb first, not > > > > the noun. > > > > > > > > > > topology_ works for me. However, I'd keep "capacity" in the names, as we > > > might need to topology_normalize_cpu_somethingelse() (etc.) in the > > > future? > > > > Worry about the future, in the future. Change the names then, _IF_ it > > becomes an issue. Try to be short and simple please. > > > > > Updated patch follows. I kept Catalin and Russell's acks as I only > > > renamed the functions, please shout if that's not OK. > > > > > > Greg, if you are fine with this approach, do you still want a complete > > > v5 of the set or can you pick this up? > > > > Am I the one who is supposed to take all of these arm-specific patches? > > If so, that's fine, but I need to have acks from the arm maintainers... > > > > Oh, and drop "capacity" please :) > > Once we have driver/base/arch_topology.c in, we want to enable (cpu > micro-architectural + max frequency (OPPmax)) invariant and frequency > (OPPmin..OPPmax) invariant load-tracking/accounting in the task scheduler > for arm and arm64. > > The way to do this is to define the task scheduler interfaces > arch_scale_cpu_capacity() and arch_scale_freq_capacity() in arch specific > code: > > #define arch_scale_cpu_capacity topology_scale_cpu_capacity > #define arch_scale_freq_capacity topology_scale_freq_capacity > > In case an arch is not defining them, the default definitions in > kernel/sched/sched.h are used. > > So topology_scale_cpu() wouldn't be correct since we scale the _capacity_ by > the micro-architectural differences (hence cpu) and not the cpu. > > Likewise we will have a function topology_scale_freq_capacity indicating > that we scale the capacity by the frequency. > > Or would you prefer something like topology_scale_capacity_by_cpu() and > topology_scale_capacity_by_freq()? I think that if you are creating an api that the scheduler will use, you need to ask the scheduler maintainers/developers what they want to see here, as that would be up to them, not me... thanks, greg k-h -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 29/05/17 12:46, Dietmar Eggemann wrote: > On 05/29/2017 11:58 AM, Greg KH wrote: > > On Mon, May 29, 2017 at 11:20:24AM +0200, Dietmar Eggemann wrote: > > > Hi Greg, > > > > > > On 05/26/2017 08:36 PM, Greg KH wrote: > > > > On Fri, May 26, 2017 at 11:10:32AM +0100, Juri Lelli wrote: > > > > > Hi, > > > > > > > > > > On 25/05/17 15:18, Greg KH wrote: > > > > > > On Thu, Apr 20, 2017 at 03:43:16PM +0100, Juri Lelli wrote: > > > > > > [...] > > > > > > > > > But this is all really topology stuff, right? Why use "capacity" at > > > > > > all: > > > > > > topology_normalize_cpu() > > > > > > topology_parse_cpu() > > > > > > topology_scale_cpu() > > > > > > topology_set_scale() > > > > > > ? > > > > > > > > > > > > It's always best to put the "subsystem" name first, we have a bad > > > > > > history of getting this wrong in the past by putting the verb first, not > > > > > > the noun. > > > > > > > > > > > [...] > > > > > > > > Oh, and drop "capacity" please :) > > > [...] > > > > I think that if you are creating an api that the scheduler will use, you > > need to ask the scheduler maintainers/developers what they want to see > > here, as that would be up to them, not me... > > The scheduler API exists already. It is arch_scale_cpu_capacity() and > arch_scale_freq_capacity() in kernel/sched/sched.h. An arch is able to > overwrite these two functions by defining them (since commit 8cd5601c5060 > and dfbca41f3479): > > #define arch_scale_cpu_capacity 'arch implementation of capacity scaling by > micro-architectural + max frequency (OPPmax)' > > #define arch_scale_freq_capacity 'arch implementation of capacity scaling by > 'frequency ((OPPmin..OPPmax)' > > There is no naming convention from the scheduler side on these functions > though. They should just express what they're doing, scaling capacity by > something. > So, discussing this naming with Morten off-line we seemed actually to agree that the following might adhere even better to what the functions actually do: topology_parse_cpu_capacity() - it parses the raw capacity-dmips-mhz values from DT; so it seems OK to leave capacity in the name here topology_set_cpu_scale() - it sets the per_cpu cpu_scale variable; so this name seems saner that the one with "_capacity" topology_get_cpu_scale() - dual of the previous one topology_normalize_cpu_scale() - it normalizes cpu_scale variables across the system CPUs (and calls topology_set_cpu_scale() to set the normalized values) Greg, does this approack look saner to you as well? If yes, I'll send a new version of the set shortly. And, as I already said on IRC, apologies for this naming fight. :) Thanks, - Juri -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/arch/arm/kernel/topology.c b/arch/arm/kernel/topology.c index 557be4f1d2d7..e53391026c1b 100644 --- a/arch/arm/kernel/topology.c +++ b/arch/arm/kernel/topology.c @@ -111,7 +111,7 @@ static void __init parse_dt_topology(void) continue; } - if (parse_cpu_capacity(cn, cpu)) { + if (atd_parse_cpu_capacity(cn, cpu)) { of_node_put(cn); continue; } @@ -160,7 +160,7 @@ static void __init parse_dt_topology(void) >> (SCHED_CAPACITY_SHIFT-1)) + 1; if (cap_from_dt) - normalize_cpu_capacity(); + atd_normalize_cpu_capacity(); } /* @@ -173,10 +173,10 @@ static void update_cpu_capacity(unsigned int cpu) if (!cpu_capacity(cpu) || cap_from_dt) return; - set_capacity_scale(cpu, cpu_capacity(cpu) / middle_capacity); + atd_set_capacity_scale(cpu, cpu_capacity(cpu) / middle_capacity); pr_info("CPU%u: update cpu_capacity %lu\n", - cpu, arch_scale_cpu_capacity(NULL, cpu)); + cpu, atd_scale_cpu_capacity(NULL, cpu)); } #else diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c index 255230c3e835..5f24faa09c05 100644 --- a/arch/arm64/kernel/topology.c +++ b/arch/arm64/kernel/topology.c @@ -39,7 +39,7 @@ static int __init get_cpu_for_node(struct device_node *node) for_each_possible_cpu(cpu) { if (of_get_cpu_node(cpu, NULL) == cpu_node) { - parse_cpu_capacity(cpu_node, cpu); + atd_parse_cpu_capacity(cpu_node, cpu); of_node_put(cpu_node); return cpu; } @@ -191,7 +191,7 @@ static int __init parse_dt_topology(void) if (ret != 0) goto out_map; - normalize_cpu_capacity(); + atd_normalize_cpu_capacity(); /* * Check that all cores are in the topology; the SMP code will diff --git a/drivers/base/arch_topology.c b/drivers/base/arch_topology.c index 76c19aa0d82f..f04999e3ff75 100644 --- a/drivers/base/arch_topology.c +++ b/drivers/base/arch_topology.c @@ -25,12 +25,12 @@ static DEFINE_MUTEX(cpu_scale_mutex); static DEFINE_PER_CPU(unsigned long, cpu_scale) = SCHED_CAPACITY_SCALE; -unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu) +unsigned long atd_scale_cpu_capacity(struct sched_domain *sd, int cpu) { return per_cpu(cpu_scale, cpu); } -void set_capacity_scale(unsigned int cpu, unsigned long capacity) +void atd_set_capacity_scale(unsigned int cpu, unsigned long capacity) { per_cpu(cpu_scale, cpu) = capacity; } @@ -42,7 +42,7 @@ static ssize_t cpu_capacity_show(struct device *dev, struct cpu *cpu = container_of(dev, struct cpu, dev); return sprintf(buf, "%lu\n", - arch_scale_cpu_capacity(NULL, cpu->dev.id)); + atd_scale_cpu_capacity(NULL, cpu->dev.id)); } static ssize_t cpu_capacity_store(struct device *dev, @@ -67,7 +67,7 @@ static ssize_t cpu_capacity_store(struct device *dev, mutex_lock(&cpu_scale_mutex); for_each_cpu(i, &cpu_topology[this_cpu].core_sibling) - set_capacity_scale(i, new_capacity); + atd_set_capacity_scale(i, new_capacity); mutex_unlock(&cpu_scale_mutex); return count; @@ -98,7 +98,7 @@ static u32 capacity_scale; static u32 *raw_capacity; static bool cap_parsing_failed; -void normalize_cpu_capacity(void) +void atd_normalize_cpu_capacity(void) { u64 capacity; int cpu; @@ -113,14 +113,14 @@ void normalize_cpu_capacity(void) cpu, raw_capacity[cpu]); capacity = (raw_capacity[cpu] << SCHED_CAPACITY_SHIFT) / capacity_scale; - set_capacity_scale(cpu, capacity); + atd_set_capacity_scale(cpu, capacity); pr_debug("cpu_capacity: CPU%d cpu_capacity=%lu\n", - cpu, arch_scale_cpu_capacity(NULL, cpu)); + cpu, atd_scale_cpu_capacity(NULL, cpu)); } mutex_unlock(&cpu_scale_mutex); } -int __init parse_cpu_capacity(struct device_node *cpu_node, int cpu) +int __init atd_parse_cpu_capacity(struct device_node *cpu_node, int cpu) { int ret = 1; u32 cpu_capacity; @@ -185,12 +185,12 @@ init_cpu_capacity_callback(struct notifier_block *nb, cpus_to_visit, policy->related_cpus); for_each_cpu(cpu, policy->related_cpus) { - raw_capacity[cpu] = arch_scale_cpu_capacity(NULL, cpu) * + raw_capacity[cpu] = atd_scale_cpu_capacity(NULL, cpu) * policy->cpuinfo.max_freq / 1000UL; capacity_scale = max(raw_capacity[cpu], capacity_scale); } if (cpumask_empty(cpus_to_visit)) { - normalize_cpu_capacity(); + atd_normalize_cpu_capacity(); kfree(raw_capacity); pr_debug("cpu_capacity: parsing done\n"); cap_parsing_done = true; diff --git a/include/linux/arch_topology.h b/include/linux/arch_topology.h index 4edae9fe8cdd..e25458d7ee9a 100644 --- a/include/linux/arch_topology.h +++ b/include/linux/arch_topology.h @@ -4,14 +4,14 @@ #ifndef _LINUX_ARCH_TOPOLOGY_H_ #define _LINUX_ARCH_TOPOLOGY_H_ -void normalize_cpu_capacity(void); +void atd_normalize_cpu_capacity(void); struct device_node; -int parse_cpu_capacity(struct device_node *cpu_node, int cpu); +int atd_parse_cpu_capacity(struct device_node *cpu_node, int cpu); struct sched_domain; -unsigned long arch_scale_cpu_capacity(struct sched_domain *sd, int cpu); +unsigned long atd_scale_cpu_capacity(struct sched_domain *sd, int cpu); -void set_capacity_scale(unsigned int cpu, unsigned long capacity); +void atd_set_capacity_scale(unsigned int cpu, unsigned long capacity); #endif /* _LINUX_ARCH_TOPOLOGY_H_ */