c10fde0d9e
If vertical cpu polarization is active then the hypervisor will dispatch certain cpus for a longer time than other cpus for maximum performance. For example if a guest would have three virtual cpus, each of them with a share of 33 percent, then in case of vertical cpu polarization all of the processing time would be combined to a single cpu which would run all the time, while the other two cpus would get nearly no cpu time. There are three different types of vertical cpus: high, medium and low. Low cpus hardly get any real cpu time, while high cpus get a full real cpu. Medium cpus get something in between. In order to switch between the two possible modes (default is horizontal) a 0 for horizontal polarization or a 1 for vertical polarization must be written to the dispatching sysfs attribute: /sys/devices/system/cpu/dispatching The polarization of each single cpu can be figured out by the polarization sysfs attribute of each cpu: /sys/devices/system/cpu/cpuX/polarization horizontal, vertical:high, vertical:medium, vertical:low or unknown. When switching polarization the polarization attribute may contain the value unknown until the configuration change is done and the kernel has figured out the new polarization of each cpu. Note that running a system with different types of vertical cpus may result in significant performance regressions. If possible only one type of vertical cpus should be used. All other cpus should be offlined. Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
113 lines
2.7 KiB
C
113 lines
2.7 KiB
C
/*
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* include/asm-s390/smp.h
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*
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* S390 version
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* Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation
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* Author(s): Denis Joseph Barrow (djbarrow@de.ibm.com,barrow_dj@yahoo.com),
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* Martin Schwidefsky (schwidefsky@de.ibm.com)
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* Heiko Carstens (heiko.carstens@de.ibm.com)
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*/
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#ifndef __ASM_SMP_H
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#define __ASM_SMP_H
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#include <linux/threads.h>
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#include <linux/cpumask.h>
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#include <linux/bitops.h>
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#if defined(__KERNEL__) && defined(CONFIG_SMP) && !defined(__ASSEMBLY__)
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#include <asm/lowcore.h>
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#include <asm/sigp.h>
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#include <asm/ptrace.h>
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/*
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s390 specific smp.c headers
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*/
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typedef struct
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{
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int intresting;
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sigp_ccode ccode;
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__u32 status;
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__u16 cpu;
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} sigp_info;
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extern void machine_restart_smp(char *);
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extern void machine_halt_smp(void);
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extern void machine_power_off_smp(void);
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#define NO_PROC_ID 0xFF /* No processor magic marker */
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/*
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* This magic constant controls our willingness to transfer
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* a process across CPUs. Such a transfer incurs misses on the L1
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* cache, and on a P6 or P5 with multiple L2 caches L2 hits. My
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* gut feeling is this will vary by board in value. For a board
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* with separate L2 cache it probably depends also on the RSS, and
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* for a board with shared L2 cache it ought to decay fast as other
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* processes are run.
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*/
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#define PROC_CHANGE_PENALTY 20 /* Schedule penalty */
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#define raw_smp_processor_id() (S390_lowcore.cpu_data.cpu_nr)
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static inline __u16 hard_smp_processor_id(void)
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{
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__u16 cpu_address;
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asm volatile("stap %0" : "=m" (cpu_address));
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return cpu_address;
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}
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/*
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* returns 1 if cpu is in stopped/check stopped state or not operational
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* returns 0 otherwise
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*/
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static inline int
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smp_cpu_not_running(int cpu)
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{
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__u32 status;
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switch (signal_processor_ps(&status, 0, cpu, sigp_sense)) {
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case sigp_order_code_accepted:
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case sigp_status_stored:
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/* Check for stopped and check stop state */
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if (status & 0x50)
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return 1;
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break;
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case sigp_not_operational:
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return 1;
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default:
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break;
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}
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return 0;
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}
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#define cpu_logical_map(cpu) (cpu)
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extern int __cpu_disable (void);
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extern void __cpu_die (unsigned int cpu);
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extern void cpu_die (void) __attribute__ ((noreturn));
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extern int __cpu_up (unsigned int cpu);
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extern struct mutex smp_cpu_state_mutex;
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extern int smp_cpu_polarization[];
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extern int smp_call_function_mask(cpumask_t mask, void (*func)(void *),
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void *info, int wait);
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#endif
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#ifndef CONFIG_SMP
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static inline void smp_send_stop(void)
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{
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/* Disable all interrupts/machine checks */
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__load_psw_mask(psw_kernel_bits & ~PSW_MASK_MCHECK);
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}
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#define hard_smp_processor_id() 0
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#define smp_cpu_not_running(cpu) 1
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#endif
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extern union save_area *zfcpdump_save_areas[NR_CPUS + 1];
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#endif
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