From 40cdab61cb2037b2066c98fe7c31b90b58228f52 Mon Sep 17 00:00:00 2001 From: Srinivas Pandruvada Date: Wed, 16 Jun 2021 15:13:28 -0700 Subject: [PATCH] platform/x86: ISST: Optimize CPU to PCI device mapping mainline inclusion from mainline-5.14 commit 1e42de8e53d32bbd7a732df49d872a30b4f888b4 category: bugfix bugzilla: https://gitee.com/openeuler/intel-kernel/issues/I6FY06 CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=1e42de8e53d32bbd7a732df49d872a30b4f888b4 Intel-SIG: commit 1e42de8e53d3 platform/x86: ISST: Optimize CPU to PCI device mapping. Backport for ISST Optimize PCI device mapping ------------------------------------------------- It was observed that some of the high performance benchmarks are spending more time in kernel depending on which CPU package they are executing. The difference is significant and benchmark scores varies more than 10%. These benchmarks adjust class of service to improve thread performance which run in parallel. This class of service change causes access to MMIO region of Intel Speed Select PCI devices depending on the CPU package they are executing. This mapping from CPU to PCI device instance uses a standard Linux PCI interface "pci_get_domain_bus_and_slot()". This function does a linear search to get to a PCI device. Since these platforms have 100+ PCI devices, this search can be expensive in fast path for benchmarks. Since the device and function of PCI device is fixed for Intel Speed Select PCI devices, the CPU to PCI device information can be cached at the same time when bus number for the CPU is read. In this way during runtime the cached information can be used. This improves performance of these benchmarks significantly. Signed-off-by: Srinivas Pandruvada Link: https://lore.kernel.org/r/20210616221329.1909276-1-srinivas.pandruvada@linux.intel.com Reviewed-by: Hans de Goede Signed-off-by: Hans de Goede Signed-off-by: yingbao jia --- .../intel_speed_select_if/isst_if_common.c | 29 +++++++++++++++---- 1 file changed, 24 insertions(+), 5 deletions(-) diff --git a/drivers/platform/x86/intel_speed_select_if/isst_if_common.c b/drivers/platform/x86/intel_speed_select_if/isst_if_common.c index 407afafc7e83..0fc9f529dcd6 100644 --- a/drivers/platform/x86/intel_speed_select_if/isst_if_common.c +++ b/drivers/platform/x86/intel_speed_select_if/isst_if_common.c @@ -281,11 +281,27 @@ static int isst_if_get_platform_info(void __user *argp) struct isst_if_cpu_info { /* For BUS 0 and BUS 1 only, which we need for PUNIT interface */ int bus_info[2]; + struct pci_dev *pci_dev[2]; int punit_cpu_id; }; static struct isst_if_cpu_info *isst_cpu_info; +static struct pci_dev *_isst_if_get_pci_dev(int cpu, int bus_no, int dev, int fn) +{ + int bus_number; + + if (bus_no < 0 || bus_no > 1 || cpu < 0 || cpu >= nr_cpu_ids || + cpu >= num_possible_cpus()) + return NULL; + + bus_number = isst_cpu_info[cpu].bus_info[bus_no]; + if (bus_number < 0) + return NULL; + + return pci_get_domain_bus_and_slot(0, bus_number, PCI_DEVFN(dev, fn)); +} + /** * isst_if_get_pci_dev() - Get the PCI device instance for a CPU * @cpu: Logical CPU number. @@ -300,17 +316,18 @@ static struct isst_if_cpu_info *isst_cpu_info; */ struct pci_dev *isst_if_get_pci_dev(int cpu, int bus_no, int dev, int fn) { - int bus_number; + struct pci_dev *pci_dev; if (bus_no < 0 || bus_no > 1 || cpu < 0 || cpu >= nr_cpu_ids || cpu >= num_possible_cpus()) return NULL; - bus_number = isst_cpu_info[cpu].bus_info[bus_no]; - if (bus_number < 0) - return NULL; + pci_dev = isst_cpu_info[cpu].pci_dev[bus_no]; - return pci_get_domain_bus_and_slot(0, bus_number, PCI_DEVFN(dev, fn)); + if (pci_dev && pci_dev->devfn == PCI_DEVFN(dev, fn)) + return pci_dev; + + return _isst_if_get_pci_dev(cpu, bus_no, dev, fn); } EXPORT_SYMBOL_GPL(isst_if_get_pci_dev); @@ -327,6 +344,8 @@ static int isst_if_cpu_online(unsigned int cpu) } else { isst_cpu_info[cpu].bus_info[0] = data & 0xff; isst_cpu_info[cpu].bus_info[1] = (data >> 8) & 0xff; + isst_cpu_info[cpu].pci_dev[0] = _isst_if_get_pci_dev(cpu, 0, 0, 1); + isst_cpu_info[cpu].pci_dev[1] = _isst_if_get_pci_dev(cpu, 1, 30, 1); } ret = rdmsrl_safe(MSR_THREAD_ID_INFO, &data); -- GitLab