| Message ID | 20200506110737.14904-3-kjain@linux.ibm.com (mailing list archive) |
|---|---|
| State | Changes Requested |
| Headers | show |
| Series | powerpc/hv-24x7: Expose chip/sockets info to add json file metric support for the hv_24x7 socket/chip level events | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (1bc92fe3175eb26ff37e580c0383d7a9abe06835) |
| snowpatch_ozlabs/checkpatch | warning | total: 0 errors, 0 warnings, 1 checks, 97 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
Hi, Kajol Jain <kjain@linux.ibm.com> writes: > diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c > index 48e8f4b17b91..8cf242aad98f 100644 > --- a/arch/powerpc/perf/hv-24x7.c > +++ b/arch/powerpc/perf/hv-24x7.c > @@ -20,6 +20,7 @@ > #include <asm/io.h> > #include <linux/byteorder/generic.h> > > +#include <asm/rtas.h> > #include "hv-24x7.h" > #include "hv-24x7-catalog.h" > #include "hv-common.h" > @@ -57,6 +58,75 @@ static bool is_physical_domain(unsigned domain) > } > } > > +/* > + * The Processor Module Information system parameter allows transferring > + * of certain processor module information from the platform to the OS. > + * Refer PAPR+ document to get parameter token value as '43'. > + */ > + > +#define PROCESSOR_MODULE_INFO 43 > +#define PROCESSOR_MAX_LENGTH (8 * 1024) > + > +DEFINE_SPINLOCK(rtas_local_data_buf_lock); > +EXPORT_SYMBOL(rtas_local_data_buf_lock); This should be static and not exported, correct? > + > +static u32 phys_sockets; /* Physical sockets */ > +static u32 phys_chipspersocket; /* Physical chips per socket*/ > +static u32 phys_coresperchip; /* Physical cores per chip */ > + > +/* > + * Function read_sys_info_pseries() make a rtas_call which require > + * data buffer of size 8K. As standard 'rtas_data_buf' is of size > + * 4K, we are adding new local buffer 'rtas_local_data_buf'. Sorry if this has been covered before but I don't understand why it would require a larger buffer; by my reading this call will return *ten bytes* of output. Also, current versions of PAPR+ limit the output length to 4002 bytes. I feel like I'm missing something. > + */ > +static __be16 rtas_local_data_buf[PROCESSOR_MAX_LENGTH] __cacheline_aligned; > + > +/* > + * read_sys_info_pseries() > + * Retrieve the number of sockets and chips per socket and cores per > + * chip details through the get-system-parameter rtas call. > + */ > +void read_sys_info_pseries(void) > +{ > + int call_status, len, ntypes; > + > + /* > + * Making system parameter: chips and sockets and cores per chip > + * default to 1. > + */ > + phys_sockets = 1; > + phys_chipspersocket = 1; > + phys_coresperchip = 1; > + memset(rtas_local_data_buf, 0, PROCESSOR_MAX_LENGTH * sizeof(__be16)); Modifying global state outside of any critical section...? How do you prevent readers from seeing inconsistent results? > + spin_lock(&rtas_local_data_buf_lock); > + > + call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1, > + NULL, > + PROCESSOR_MODULE_INFO, > + __pa(rtas_local_data_buf), > + PROCESSOR_MAX_LENGTH); > + > + spin_unlock(&rtas_local_data_buf_lock); Using this lock this way fails to provide any protection to the data buffer or the phys_* variables. > + > + if (call_status != 0) { > + pr_info("Error calling get-system-parameter (0x%x)\n", > + call_status); To be robust, this should handle busy (-2) and extended delay (990x) statuses. And if it's going to log errors it should use pr_err() and use decimal, not hex, to report the RTAS call status, since that's how they're specified in PAPR+.
On 5/12/20 2:37 AM, Nathan Lynch wrote: > Hi, > > Kajol Jain <kjain@linux.ibm.com> writes: >> diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c >> index 48e8f4b17b91..8cf242aad98f 100644 >> --- a/arch/powerpc/perf/hv-24x7.c >> +++ b/arch/powerpc/perf/hv-24x7.c >> @@ -20,6 +20,7 @@ >> #include <asm/io.h> >> #include <linux/byteorder/generic.h> >> >> +#include <asm/rtas.h> >> #include "hv-24x7.h" >> #include "hv-24x7-catalog.h" >> #include "hv-common.h" >> @@ -57,6 +58,75 @@ static bool is_physical_domain(unsigned domain) >> } >> } >> >> +/* >> + * The Processor Module Information system parameter allows transferring >> + * of certain processor module information from the platform to the OS. >> + * Refer PAPR+ document to get parameter token value as '43'. >> + */ >> + >> +#define PROCESSOR_MODULE_INFO 43 >> +#define PROCESSOR_MAX_LENGTH (8 * 1024) >> + >> +DEFINE_SPINLOCK(rtas_local_data_buf_lock); >> +EXPORT_SYMBOL(rtas_local_data_buf_lock); > > This should be static and not exported, correct? > >> + >> +static u32 phys_sockets; /* Physical sockets */ >> +static u32 phys_chipspersocket; /* Physical chips per socket*/ >> +static u32 phys_coresperchip; /* Physical cores per chip */ >> + >> +/* >> + * Function read_sys_info_pseries() make a rtas_call which require >> + * data buffer of size 8K. As standard 'rtas_data_buf' is of size >> + * 4K, we are adding new local buffer 'rtas_local_data_buf'. > > Sorry if this has been covered before but I don't understand why it > would require a larger buffer; by my reading this call will return *ten > bytes* of output. Also, current versions of PAPR+ limit the output > length to 4002 bytes. I feel like I'm missing something. > Hi Nathan, Thanks for reviewing the patch. Actually when I was testing this patch in both power8 and power9 machine, I got some issue in power9 because of buffer size. And I checked the buffer size used in util_linux which is 8192. So, I increase the buffer size.I will again test it as I did couple of changes after that with 4002 size. > >> + */ >> +static __be16 rtas_local_data_buf[PROCESSOR_MAX_LENGTH] __cacheline_aligned; >> + >> +/* >> + * read_sys_info_pseries() >> + * Retrieve the number of sockets and chips per socket and cores per >> + * chip details through the get-system-parameter rtas call. >> + */ >> +void read_sys_info_pseries(void) >> +{ >> + int call_status, len, ntypes; >> + >> + /* >> + * Making system parameter: chips and sockets and cores per chip >> + * default to 1. >> + */ >> + phys_sockets = 1; >> + phys_chipspersocket = 1; >> + phys_coresperchip = 1; >> + memset(rtas_local_data_buf, 0, PROCESSOR_MAX_LENGTH * sizeof(__be16)); > > Modifying global state outside of any critical section...? How do > you prevent readers from seeing inconsistent results? Yes right, Will update. > > >> + spin_lock(&rtas_local_data_buf_lock); >> + >> + call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1, >> + NULL, >> + PROCESSOR_MODULE_INFO, >> + __pa(rtas_local_data_buf), >> + PROCESSOR_MAX_LENGTH); >> + >> + spin_unlock(&rtas_local_data_buf_lock); > > Using this lock this way fails to provide any protection to the data > buffer or the phys_* variables. > > >> + >> + if (call_status != 0) { >> + pr_info("Error calling get-system-parameter (0x%x)\n", >> + call_status); > > To be robust, this should handle busy (-2) and extended delay (990x) > statuses. And if it's going to log errors it should use pr_err() and use > decimal, not hex, to report the RTAS call status, since that's how > they're specified in PAPR+. Thanks for pointing it, Will update. Thanks, Kajol Jain
diff --git a/arch/powerpc/include/asm/rtas.h b/arch/powerpc/include/asm/rtas.h index 3c1887351c71..1c11f814932d 100644 --- a/arch/powerpc/include/asm/rtas.h +++ b/arch/powerpc/include/asm/rtas.h @@ -482,6 +482,7 @@ static inline void rtas_initialize(void) { }; #endif extern int call_rtas(const char *, int, int, unsigned long *, ...); +extern void read_sys_info_pseries(void); #endif /* __KERNEL__ */ #endif /* _POWERPC_RTAS_H */ diff --git a/arch/powerpc/perf/hv-24x7.c b/arch/powerpc/perf/hv-24x7.c index 48e8f4b17b91..8cf242aad98f 100644 --- a/arch/powerpc/perf/hv-24x7.c +++ b/arch/powerpc/perf/hv-24x7.c @@ -20,6 +20,7 @@ #include <asm/io.h> #include <linux/byteorder/generic.h> +#include <asm/rtas.h> #include "hv-24x7.h" #include "hv-24x7-catalog.h" #include "hv-common.h" @@ -57,6 +58,75 @@ static bool is_physical_domain(unsigned domain) } } +/* + * The Processor Module Information system parameter allows transferring + * of certain processor module information from the platform to the OS. + * Refer PAPR+ document to get parameter token value as '43'. + */ + +#define PROCESSOR_MODULE_INFO 43 +#define PROCESSOR_MAX_LENGTH (8 * 1024) + +DEFINE_SPINLOCK(rtas_local_data_buf_lock); +EXPORT_SYMBOL(rtas_local_data_buf_lock); + +static u32 phys_sockets; /* Physical sockets */ +static u32 phys_chipspersocket; /* Physical chips per socket*/ +static u32 phys_coresperchip; /* Physical cores per chip */ + +/* + * Function read_sys_info_pseries() make a rtas_call which require + * data buffer of size 8K. As standard 'rtas_data_buf' is of size + * 4K, we are adding new local buffer 'rtas_local_data_buf'. + */ +static __be16 rtas_local_data_buf[PROCESSOR_MAX_LENGTH] __cacheline_aligned; + +/* + * read_sys_info_pseries() + * Retrieve the number of sockets and chips per socket and cores per + * chip details through the get-system-parameter rtas call. + */ +void read_sys_info_pseries(void) +{ + int call_status, len, ntypes; + + /* + * Making system parameter: chips and sockets and cores per chip + * default to 1. + */ + phys_sockets = 1; + phys_chipspersocket = 1; + phys_coresperchip = 1; + memset(rtas_local_data_buf, 0, PROCESSOR_MAX_LENGTH * sizeof(__be16)); + spin_lock(&rtas_local_data_buf_lock); + + call_status = rtas_call(rtas_token("ibm,get-system-parameter"), 3, 1, + NULL, + PROCESSOR_MODULE_INFO, + __pa(rtas_local_data_buf), + PROCESSOR_MAX_LENGTH); + + spin_unlock(&rtas_local_data_buf_lock); + + if (call_status != 0) { + pr_info("Error calling get-system-parameter (0x%x)\n", + call_status); + } else { + rtas_local_data_buf[PROCESSOR_MAX_LENGTH - 1] = '\0'; + len = be16_to_cpup((__be16 *)&rtas_local_data_buf[0]); + if (len < 4) + return; + + ntypes = be16_to_cpup(&rtas_local_data_buf[1]); + + if (!ntypes) + return; + phys_sockets = be16_to_cpup(&rtas_local_data_buf[2]); + phys_chipspersocket = be16_to_cpup(&rtas_local_data_buf[3]); + phys_coresperchip = be16_to_cpup(&rtas_local_data_buf[4]); + } +} + /* Domains for which more than one result element are returned for each event. */ static bool domain_needs_aggregation(unsigned int domain) { @@ -1605,6 +1675,8 @@ static int hv_24x7_init(void) if (r) return r; + read_sys_info_pseries(); + return 0; }
For hv_24x7 socket/chip level events, specific chip-id to which the data requested should be added as part of pmu events. But number of chips/socket in the system details are not exposed. Patch implements read_sys_info_pseries() to get system parameter values like number of sockets and chips per socket. Rtas_call with token "PROCESSOR_MODULE_INFO" is used to get these values. Sub-sequent patch exports these values via sysfs. Patch also make these parameters default to 1. Signed-off-by: Kajol Jain <kjain@linux.ibm.com> --- arch/powerpc/include/asm/rtas.h | 1 + arch/powerpc/perf/hv-24x7.c | 72 +++++++++++++++++++++++++++++++++ 2 files changed, 73 insertions(+)