#include #include #include #include #include #include #include #include #include #include "xenfs.h" #define XEN_KSYM_NAME_LEN 127 /* Hypervisor may have different name length */ struct xensyms { struct xen_platform_op op; char *name; uint32_t namelen; }; /* Grab next output page from the hypervisor */ static int xensyms_next_sym(struct xensyms *xs) { int ret; struct xenpf_symdata *symdata = &xs->op.u.symdata; uint64_t symnum; memset(xs->name, 0, xs->namelen); symdata->namelen = xs->namelen; symnum = symdata->symnum; ret = HYPERVISOR_platform_op(&xs->op); if (ret < 0) return ret; /* * If hypervisor's symbol didn't fit into the buffer then allocate * a larger buffer and try again. */ if (unlikely(symdata->namelen > xs->namelen)) { kfree(xs->name); xs->namelen = symdata->namelen; xs->name = kzalloc(xs->namelen, GFP_KERNEL); if (!xs->name) return -ENOMEM; set_xen_guest_handle(symdata->name, xs->name); symdata->symnum--; /* Rewind */ ret = HYPERVISOR_platform_op(&xs->op); if (ret < 0) return ret; } if (symdata->symnum == symnum) /* End of symbols */ return 1; return 0; } static void *xensyms_start(struct seq_file *m, loff_t *pos) { struct xensyms *xs = (struct xensyms *)m->private; xs->op.u.symdata.symnum = *pos; if (xensyms_next_sym(xs)) return NULL; return m->private; } static void *xensyms_next(struct seq_file *m, void *p, loff_t *pos) { struct xensyms *xs = (struct xensyms *)m->private; xs->op.u.symdata.symnum = ++(*pos); if (xensyms_next_sym(xs)) return NULL; return p; } static int xensyms_show(struct seq_file *m, void *p) { struct xensyms *xs = (struct xensyms *)m->private; struct xenpf_symdata *symdata = &xs->op.u.symdata; seq_printf(m, "%016llx %c %s\n", symdata->address, symdata->type, xs->name); return 0; } static void xensyms_stop(struct seq_file *m, void *p) { } static const struct seq_operations xensyms_seq_ops = { .start = xensyms_start, .next = xensyms_next, .show = xensyms_show, .stop = xensyms_stop, }; static int xensyms_open(struct inode *inode, struct file *file) { struct seq_file *m; struct xensyms *xs; int ret; ret = seq_open_private(file, &xensyms_seq_ops, sizeof(struct xensyms)); if (ret) return ret; m = file->private_data; xs = (struct xensyms *)m->private; xs->namelen = XEN_KSYM_NAME_LEN + 1; xs->name = kzalloc(xs->namelen, GFP_KERNEL); if (!xs->name) { seq_release_private(inode, file); return -ENOMEM; } set_xen_guest_handle(xs->op.u.symdata.name, xs->name); xs->op.cmd = XENPF_get_symbol; xs->op.u.symdata.namelen = xs->namelen; return 0; } static int xensyms_release(struct inode *inode, struct file *file) { struct seq_file *m = file->private_data; struct xensyms *xs = (struct xensyms *)m->private; kfree(xs->name); return seq_release_private(inode, file); } const struct file_operations xensyms_ops = { .open = xensyms_open, .read = seq_read, .llseek = seq_lseek, .release = xensyms_release }; ='/cgit.cgi/linux/net-next.git/commit/tools/testing/selftests?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>selftests/powerpc/pmu/event.c
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authorSrinivas Pandruvada <srinivas.pandruvada@linux.intel.com>2017-02-03 14:18:39 -0800
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2017-02-04 00:11:08 +0100
commit6e978b22efa1db9f6e71b24440b5f1d93e968ee3 (patch)
treec666f7a26b860674848949e39a610222b0723f89 /tools/testing/selftests/powerpc/pmu/event.c
parent3c223c19aea85d3dda1416c187915f4a30b04b1f (diff)
cpufreq: intel_pstate: Disable energy efficiency optimization
Some Kabylake desktop processors may not reach max turbo when running in HWP mode, even if running under sustained 100% utilization. This occurs when the HWP.EPP (Energy Performance Preference) is set to "balance_power" (0x80) -- the default on most systems. It occurs because the platform BIOS may erroneously enable an energy-efficiency setting -- MSR_IA32_POWER_CTL BIT-EE, which is not recommended to be enabled on this SKU. On the failing systems, this BIOS issue was not discovered when the desktop motherboard was tested with Windows, because the BIOS also neglects to provide the ACPI/CPPC table, that Windows requires to enable HWP, and so Windows runs in legacy P-state mode, where this setting has no effect. Linux' intel_pstate driver does not require ACPI/CPPC to enable HWP, and so it runs in HWP mode, exposing this incorrect BIOS configuration. There are several ways to address this problem. First, Linux can also run in legacy P-state mode on this system. As intel_pstate is how Linux enables HWP, booting with "intel_pstate=disable" will run in acpi-cpufreq/ondemand legacy p-state mode. Or second, the "performance" governor can be used with intel_pstate, which will modify HWP.EPP to 0. Or third, starting in 4.10, the /sys/devices/system/cpu/cpufreq/policy*/energy_performance_preference attribute in can be updated from "balance_power" to "performance". Or fourth, apply this patch, which fixes the erroneous setting of MSR_IA32_POWER_CTL BIT_EE on this model, allowing the default configuration to function as designed. Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> Reviewed-by: Len Brown <len.brown@intel.com> Cc: 4.6+ <stable@vger.kernel.org> # 4.6+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'tools/testing/selftests/powerpc/pmu/event.c')