kernel.git/arch/x86/kernel/cpu/intel_rdt.h, branch linux-4.18.y

x86/intel_rdt/mba_sc: Feedback loop to dynamically update mem bandwidth

2018-05-19T11:16:44Z

mba_sc is a feedback loop where we periodically read MBM counters and try to restrict the bandwidth below a max value so the below is always true: "current bandwidth(cur_bw) < user specified bandwidth(user_bw)" The frequency of these checks is currently 1s and we just tag along the MBM overflow timer to do the updates. Doing it once in a second also makes the calculation of bandwidth easy. The steps of increase or decrease of bandwidth is the minimum granularity specified by the hardware. Although the MBA's goal is to restrict the bandwidth below a maximum, there may be a need to even increase the bandwidth. Since MBA controls the L2 external bandwidth where as MBM measures the L3 external bandwidth, we may end up restricting some rdtgroups unnecessarily. This may happen in the sequence where rdtgroup (set of jobs) had high "L3 <-> memory traffic" in initial phases -> mba_sc kicks in and reduced bandwidth percentage values -> but after some it has mostly "L2 <-> L3" traffic. In this scenario mba_sc increases the bandwidth percentage when there is lesser memory traffic. Signed-off-by: Vikas Shivappa Signed-off-by: Thomas Gleixner Cc: ravi.v.shankar@intel.com Cc: tony.luck@intel.com Cc: fenghua.yu@intel.com Cc: vikas.shivappa@intel.com Cc: ak@linux.intel.com Cc: hpa@zytor.com Link: https://lkml.kernel.org/r/1524263781-14267-7-git-send-email-vikas.shivappa@linux.intel.com

x86/intel_rdt/mba_sc: Prepare for feedback loop

2018-05-19T11:16:44Z

This is a preparatory patch for the mba feedback loop. Add support to measure the "bandwidth in MBps" and the "delta bandwidth". Measure it by reading the MBM IA32_QM_CTR MSRs and calculating the amount of "bytes" moved. There is no user space interface for this and will only be used by the feedback loop patch. Signed-off-by: Vikas Shivappa Signed-off-by: Thomas Gleixner Cc: ravi.v.shankar@intel.com Cc: tony.luck@intel.com Cc: fenghua.yu@intel.com Cc: vikas.shivappa@intel.com Cc: ak@linux.intel.com Cc: hpa@zytor.com Link: https://lkml.kernel.org/r/1524263781-14267-6-git-send-email-vikas.shivappa@linux.intel.com

x86/intel_rdt/mba_sc: Add initialization support

2018-05-19T11:16:43Z

When MBA software controller is enabled, a per domain storage is required for user specified bandwidth in "MBps" and the "percentage" values which are programmed into the IA32_MBA_THRTL_MSR. Add support for these data structures and initialization. The MBA percentage values have a default max value of 100 but however the max value in MBps is not available from the hardware so it's set to U32_MAX. This simply says that the control group can use all bandwidth by default but does not say what is the actual max bandwidth available. The actual bandwidth that is available may depend on lot of factors like QPI link, number of memory channels, memory channel frequency, its width and memory speed, how many channels are configured and also if memory interleaving is enabled. So there is no way to determine the maximum at runtime reliably. Signed-off-by: Vikas Shivappa Signed-off-by: Thomas Gleixner Cc: ravi.v.shankar@intel.com Cc: tony.luck@intel.com Cc: fenghua.yu@intel.com Cc: vikas.shivappa@intel.com Cc: ak@linux.intel.com Cc: hpa@zytor.com Link: https://lkml.kernel.org/r/1524263781-14267-4-git-send-email-vikas.shivappa@linux.intel.com

x86/intel_rdt/mba_sc: Enable/disable MBA software controller

2018-05-19T11:16:43Z

Currently user does memory bandwidth allocation(MBA) by specifying the bandwidth in percentage via the resctrl schemata file: "/sys/fs/resctrl/schemata" Add a new mount option "mba_MBps" to enable the user to specify MBA in MBps: $mount -t resctrl resctrl [-o cdp[,cdpl2][mba_MBps]] /sys/fs/resctrl Signed-off-by: Vikas Shivappa Signed-off-by: Thomas Gleixner Cc: ravi.v.shankar@intel.com Cc: tony.luck@intel.com Cc: fenghua.yu@intel.com Cc: vikas.shivappa@intel.com Cc: ak@linux.intel.com Cc: hpa@zytor.com Link: https://lkml.kernel.org/r/1524263781-14267-3-git-send-email-vikas.shivappa@linux.intel.com

x86/intel_rdt: Enable L2 CDP in MSR IA32_L2_QOS_CFG

2018-01-18T08:33:31Z

Bit 0 in MSR IA32_L2_QOS_CFG (0xc82) is L2 CDP enable bit. By default, the bit is zero, i.e. L2 CAT is enabled, and L2 CDP is disabled. When the resctrl mount parameter "cdpl2" is given, the bit is set to 1 and L2 CDP is enabled. In L2 CDP mode, the L2 CAT mask MSRs are re-mapped into interleaved pairs of mask MSRs for code (referenced by an odd CLOSID) and data (referenced by an even CLOSID). Signed-off-by: Fenghua Yu Signed-off-by: Thomas Gleixner Cc: "Ravi V Shankar" Cc: "Tony Luck" Cc: Vikas" Cc: Sai Praneeth" Cc: Reinette" Link: https://lkml.kernel.org/r/1513810644-78015-6-git-send-email-fenghua.yu@intel.com

x86/intel_rdt: Add two new resources for L2 Code and Data Prioritization (CDP)

2018-01-18T08:33:31Z

L2 data and L2 code are added as new resources in rdt_resources_all[] and data in the resources are configured. When L2 CDP is enabled, the schemata will have the two resources in this format: L2DATA:l2id0=xxxx;l2id1=xxxx;.... L2CODE:l2id0=xxxx;l2id1=xxxx;.... xxxx represent CBM (Cache Bit Mask) values in the schemata, similar to all others (L2 CAT/L3 CAT/L3 CDP). Signed-off-by: Fenghua Yu Signed-off-by: Thomas Gleixner Cc: "Ravi V Shankar" Cc: "Tony Luck" Cc: Vikas" Cc: Sai Praneeth" Cc: Reinette" Link: https://lkml.kernel.org/r/1513810644-78015-5-git-send-email-fenghua.yu@intel.com

Merge branch 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2017-11-14T03:05:19Z

Pull x86 cache resource updates from Thomas Gleixner: "This update provides updates to RDT: - A diagnostic framework for the Resource Director Technology (RDT) user interface (sysfs). The failure modes of the user interface are hard to diagnose from the error codes. An extra last command status file provides now sensible textual information about the failure so its simpler to use. - A few minor cleanups and updates in the RDT code" * 'x86-cache-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/intel_rdt: Fix a silent failure when writing zero value schemata x86/intel_rdt: Fix potential deadlock during resctrl mount x86/intel_rdt: Fix potential deadlock during resctrl unmount x86/intel_rdt: Initialize bitmask of shareable resource if CDP enabled x86/intel_rdt: Remove redundant assignment x86/intel_rdt/cqm: Make integer rmid_limbo_count static x86/intel_rdt: Add documentation for "info/last_cmd_status" x86/intel_rdt: Add diagnostics when making directories x86/intel_rdt: Add diagnostics when writing the cpus file x86/intel_rdt: Add diagnostics when writing the tasks file x86/intel_rdt: Add diagnostics when writing the schemata file x86/intel_rdt: Add framework for better RDT UI diagnostics

License cleanup: add SPDX GPL-2.0 license identifier to files with no license

2017-11-02T10:10:55Z

Many source files in the tree are missing licensing information, which makes it harder for compliance tools to determine the correct license. By default all files without license information are under the default license of the kernel, which is GPL version 2. Update the files which contain no license information with the 'GPL-2.0' SPDX license identifier. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This patch is based on work done by Thomas Gleixner and Kate Stewart and Philippe Ombredanne. How this work was done: Patches were generated and checked against linux-4.14-rc6 for a subset of the use cases: - file had no licensing information it it. - file was a */uapi/* one with no licensing information in it, - file was a */uapi/* one with existing licensing information, Further patches will be generated in subsequent months to fix up cases where non-standard license headers were used, and references to license had to be inferred by heuristics based on keywords. The analysis to determine which SPDX License Identifier to be applied to a file was done in a spreadsheet of side by side results from of the output of two independent scanners (ScanCode & Windriver) producing SPDX tag:value files created by Philippe Ombredanne. Philippe prepared the base worksheet, and did an initial spot review of a few 1000 files. The 4.13 kernel was the starting point of the analysis with 60,537 files assessed. Kate Stewart did a file by file comparison of the scanner results in the spreadsheet to determine which SPDX license identifier(s) to be applied to the file. She confirmed any determination that was not immediately clear with lawyers working with the Linux Foundation. Criteria used to select files for SPDX license identifier tagging was: - Files considered eligible had to be source code files. - Make and config files were included as candidates if they contained >5 lines of source - File already had some variant of a license header in it (even if <5 lines). All documentation files were explicitly excluded. The following heuristics were used to determine which SPDX license identifiers to apply. - when both scanners couldn't find any license traces, file was considered to have no license information in it, and the top level COPYING file license applied. For non */uapi/* files that summary was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 11139 and resulted in the first patch in this series. If that file was a */uapi/* path one, it was "GPL-2.0 WITH Linux-syscall-note" otherwise it was "GPL-2.0". Results of that was: SPDX license identifier # files ---------------------------------------------------|------- GPL-2.0 WITH Linux-syscall-note 930 and resulted in the second patch in this series. - if a file had some form of licensing information in it, and was one of the */uapi/* ones, it was denoted with the Linux-syscall-note if any GPL family license was found in the file or had no licensing in it (per prior point). Results summary: SPDX license identifier # files ---------------------------------------------------|------ GPL-2.0 WITH Linux-syscall-note 270 GPL-2.0+ WITH Linux-syscall-note 169 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-2-Clause) 21 ((GPL-2.0 WITH Linux-syscall-note) OR BSD-3-Clause) 17 LGPL-2.1+ WITH Linux-syscall-note 15 GPL-1.0+ WITH Linux-syscall-note 14 ((GPL-2.0+ WITH Linux-syscall-note) OR BSD-3-Clause) 5 LGPL-2.0+ WITH Linux-syscall-note 4 LGPL-2.1 WITH Linux-syscall-note 3 ((GPL-2.0 WITH Linux-syscall-note) OR MIT) 3 ((GPL-2.0 WITH Linux-syscall-note) AND MIT) 1 and that resulted in the third patch in this series. - when the two scanners agreed on the detected license(s), that became the concluded license(s). - when there was disagreement between the two scanners (one detected a license but the other didn't, or they both detected different licenses) a manual inspection of the file occurred. - In most cases a manual inspection of the information in the file resulted in a clear resolution of the license that should apply (and which scanner probably needed to revisit its heuristics). - When it was not immediately clear, the license identifier was confirmed with lawyers working with the Linux Foundation. - If there was any question as to the appropriate license identifier, the file was flagged for further research and to be revisited later in time. In total, over 70 hours of logged manual review was done on the spreadsheet to determine the SPDX license identifiers to apply to the source files by Kate, Philippe, Thomas and, in some cases, confirmation by lawyers working with the Linux Foundation. Kate also obtained a third independent scan of the 4.13 code base from FOSSology, and compared selected files where the other two scanners disagreed against that SPDX file, to see if there was new insights. The Windriver scanner is based on an older version of FOSSology in part, so they are related. Thomas did random spot checks in about 500 files from the spreadsheets for the uapi headers and agreed with SPDX license identifier in the files he inspected. For the non-uapi files Thomas did random spot checks in about 15000 files. In initial set of patches against 4.14-rc6, 3 files were found to have copy/paste license identifier errors, and have been fixed to reflect the correct identifier. Additionally Philippe spent 10 hours this week doing a detailed manual inspection and review of the 12,461 patched files from the initial patch version early this week with: - a full scancode scan run, collecting the matched texts, detected license ids and scores - reviewing anything where there was a license detected (about 500+ files) to ensure that the applied SPDX license was correct - reviewing anything where there was no detection but the patch license was not GPL-2.0 WITH Linux-syscall-note to ensure that the applied SPDX license was correct This produced a worksheet with 20 files needing minor correction. This worksheet was then exported into 3 different .csv files for the different types of files to be modified. These .csv files were then reviewed by Greg. Thomas wrote a script to parse the csv files and add the proper SPDX tag to the file, in the format that the file expected. This script was further refined by Greg based on the output to detect more types of files automatically and to distinguish between header and source .c files (which need different comment types.) Finally Greg ran the script using the .csv files to generate the patches. Reviewed-by: Kate Stewart Reviewed-by: Philippe Ombredanne Reviewed-by: Thomas Gleixner Signed-off-by: Greg Kroah-Hartman

x86/intel_rdt: Add framework for better RDT UI diagnostics

2017-09-27T10:10:10Z

Commands are given to the resctrl file system by making/removing directories, or by writing to files. When something goes wrong the user is generally left wondering why they got: bash: echo: write error: Invalid argument Add a new file "last_cmd_status" to the "info" directory that will give the user some better clues on what went wrong. Provide functions to clear and update last_cmd_status which check that we hold the rdtgroup_mutex. [ tglx: Made last_cmd_status static and folded back the hunk from patch 3 which replaces the open coded access to last_cmd_status with the accessor function ] Signed-off-by: Tony Luck Signed-off-by: Thomas Gleixner Cc: Fenghua Yu Cc: Steven Rostedt Cc: Vikas Shivappa Cc: Boris Petkov Cc: Reinette Chatre Link: https://lkml.kernel.org/r/edc4e0e9741eee89bba569f0021b1b2662fd9508.1506382469.git.tony.luck@intel.com

x86/intel_rdt/cqm: Improve limbo list processing

2017-08-16T10:05:41Z

During a mkdir, the entire limbo list is synchronously checked on each package for free RMIDs by sending IPIs. With a large number of RMIDs (SKL has 192) this creates a intolerable amount of work in IPIs. Replace the IPI based checking of the limbo list with asynchronous worker threads on each package which periodically scan the limbo list and move the RMIDs that have: llc_occupancy < threshold_occupancy on all packages to the free list. mkdir now returns -ENOSPC if the free list and the limbo list ere empty or returns -EBUSY if there are RMIDs on the limbo list and the free list is empty. Getting rid of the IPIs also simplifies the data structures and the serialization required for handling the lists. [ tglx: Rewrote changelog ... ] Signed-off-by: Vikas Shivappa Signed-off-by: Thomas Gleixner Cc: ravi.v.shankar@intel.com Cc: tony.luck@intel.com Cc: fenghua.yu@intel.com Cc: peterz@infradead.org Cc: eranian@google.com Cc: vikas.shivappa@intel.com Cc: ak@linux.intel.com Cc: davidcc@google.com Link: http://lkml.kernel.org/r/1502845243-20454-3-git-send-email-vikas.shivappa@linux.intel.com