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2018-09-28x86/intel_rdt: Use perf infrastructure for measurementsReinette Chatre1-8/+14
The success of a cache pseudo-locked region is measured using performance monitoring events that are programmed directly at the time the user requests a measurement. Modifying the performance event registers directly is not appropriate since it circumvents the in-kernel perf infrastructure that exists to manage these resources and provide resource arbitration to the performance monitoring hardware. The cache pseudo-locking measurements are modified to use the in-kernel perf infrastructure. Performance events are created and validated with the appropriate perf API. The performance counters are still read as directly as possible to avoid the additional cache hits. This is done safely by first ensuring with the perf API that the counters have been programmed correctly and only accessing the counters in an interrupt disabled section where they are not able to be moved. As part of the transition to the in-kernel perf infrastructure the L2 and L3 measurements are split into two separate measurements that can be triggered independently. This separation prevents additional cache misses incurred during the extra testing code used to decide if a L2 and/or L3 measurement should be made. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: fenghua.yu@intel.com Cc: tony.luck@intel.com Cc: peterz@infradead.org Cc: acme@kernel.org Cc: gavin.hindman@intel.com Cc: jithu.joseph@intel.com Cc: dave.hansen@intel.com Cc: hpa@zytor.com Link: https://lkml.kernel.org/r/fc24e728b446404f42c78573c506e98cd0599873.1537468643.git.reinette.chatre@intel.com
2018-07-03x86/intel_rdt: Make CPU information accessible for pseudo-locked regionsReinette Chatre1-0/+3
When a resource group enters pseudo-locksetup mode it reflects that the platform supports cache pseudo-locking and the resource group is unused, ready to be used for a pseudo-locked region. Until it is set up as a pseudo-locked region the resource group is "locked down" such that no new tasks or cpus can be assigned to it. This is accomplished in a user visible way by making the cpus, cpus_list, and tasks resctrl files inaccassible (user cannot read from or write to these files). When the resource group changes to pseudo-locked mode it represents a cache pseudo-locked region. While not appropriate to make any changes to the cpus assigned to this region it is useful to make it easy for the user to see which cpus are associated with the pseudo-locked region. Modify the permissions of the cpus/cpus_list file when the resource group changes to pseudo-locked mode to support reading (not writing). The information presented to the user when reading the file are the cpus associated with the pseudo-locked region. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: fenghua.yu@intel.com Cc: tony.luck@intel.com Cc: vikas.shivappa@linux.intel.com Cc: gavin.hindman@intel.com Cc: jithu.joseph@intel.com Cc: dave.hansen@intel.com Cc: hpa@zytor.com Link: https://lkml.kernel.org/r/12756b7963b6abc1bffe8fb560b87b75da827bd1.1530421961.git.reinette.chatre@intel.com
2018-06-24x86/intel_rdt: Limit C-states dynamically when pseudo-locking activeReinette Chatre1-2/+2
Deeper C-states impact cache content through shrinking of the cache or flushing entire cache to memory before reducing power to the cache. Deeper C-states will thus negatively impact the pseudo-locked regions. To avoid impacting pseudo-locked regions C-states are limited on pseudo-locked region creation so that cores associated with the pseudo-locked region are prevented from entering deeper C-states. This is accomplished by requesting a CPU latency target which will prevent the core from entering C6 across all supported platforms. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: fenghua.yu@intel.com Cc: tony.luck@intel.com Cc: vikas.shivappa@linux.intel.com Cc: gavin.hindman@intel.com Cc: jithu.joseph@intel.com Cc: dave.hansen@intel.com Cc: hpa@zytor.com Link: https://lkml.kernel.org/r/1ef4f99dd6ba12fa6fb44c5a1141e75f952b9cd9.1529706536.git.reinette.chatre@intel.com
2018-06-23x86/intel_rdt: Documentation for Cache Pseudo-LockingReinette Chatre1-2/+278
Add description of Cache Pseudo-Locking feature, its interface, as well as an example of its usage. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: fenghua.yu@intel.com Cc: tony.luck@intel.com Cc: vikas.shivappa@linux.intel.com Cc: gavin.hindman@intel.com Cc: jithu.joseph@intel.com Cc: dave.hansen@intel.com Cc: hpa@zytor.com Link: https://lkml.kernel.org/r/6e118c15d2c254a27b8891783505cd1bb94a2b10.1529706536.git.reinette.chatre@intel.com
2018-06-23x86/intel_rdt: Document new mode, size, and bit_usageReinette Chatre1-2/+97
By default resource groups allow sharing of their cache allocations. There is nothing that prevents a resource group from configuring a cache allocation that overlaps with that of an existing resource group. To enable resource groups to specify that their cache allocations cannot be shared a resource group "mode" is introduced to support two possible modes: "shareable" and "exclusive". A "shareable" resource group allows sharing of its cache allocations, an "exclusive" resource group does not. A new resctrl file "mode" associated with each resource group is used to communicate its (the associated resource group's) mode setting and allow the mode to be changed. The new "mode" file as well as two other resctrl files, "bit_usage" and "size", are introduced in this series. Add documentation for the three new resctrl files as well as one example demonstrating their use. Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: fenghua.yu@intel.com Cc: tony.luck@intel.com Cc: vikas.shivappa@linux.intel.com Cc: gavin.hindman@intel.com Cc: jithu.joseph@intel.com Cc: dave.hansen@intel.com Cc: hpa@zytor.com Link: https://lkml.kernel.org/r/f03a3059ec40ae719be6f3fba9f446bb055e0064.1529706536.git.reinette.chatre@intel.com
2018-05-19x86/intel_rdt/mba_sc: Documentation for MBA software controller(mba_sc)Vikas Shivappa1-8/+67
Add documentation about the feedback loop mechanism (MBA software controller) which lets the user specify the memory bandwidth allocation in MBps. This includes some changes to "schemata" formati with examples. Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> 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/1524263781-14267-2-git-send-email-vikas.shivappa@linux.intel.com
2018-02-28Documentation, x86, resctrl: Make text and sample command matchLi RongQing1-1/+1
The text says "Move the cpus 4-7 over to p1", but the sample command writes to p0/cpus. Signed-off-by: Li RongQing <lirongqing@baidu.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: fenghua.yu@intel.com Cc: linux-doc@vger.kernel.org Link: https://lkml.kernel.org/r/1519712271-8802-1-git-send-email-lirongqing@baidu.com
2018-01-18x86/intel_rdt: Add L2CDP support in documentationFenghua Yu1-2/+5
L2 and L3 Code and Data Prioritization (CDP) can be enabled separately. The existing mount parameter "cdp" is only for enabling L3 CDP and will be kept for backwards compability. Add a new mount parameter 'cdpl2' for L2 CDP. [ tglx: Made changelog readable ] Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: Vikas" <vikas.shivappa@intel.com> Cc: Sai Praneeth" <sai.praneeth.prakhya@intel.com> Cc: Reinette" <reinette.chatre@intel.com> Link: https://lkml.kernel.org/r/1513810644-78015-3-git-send-email-fenghua.yu@intel.com
2018-01-18x86/intel_rdt: Update documentationFenghua Yu1-1/+7
With more flag bits in /proc/cpuinfo for RDT, it's better to classify the bits for readability. Some previously missing bits are added as well. Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: Vikas" <vikas.shivappa@intel.com> Cc: Sai Praneeth" <sai.praneeth.prakhya@intel.com> Cc: Reinette" <reinette.chatre@intel.com> Link: https://lkml.kernel.org/r/1513810644-78015-2-git-send-email-fenghua.yu@intel.com
2017-09-27x86/intel_rdt: Add documentation for "info/last_cmd_status"Tony Luck1-0/+11
New file in the "info" directory helps diagnose what went wrong when using the /sys/fs/resctrl file system Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Vikas Shivappa <vikas.shivappa@intel.com> Cc: Boris Petkov <bp@suse.de> Cc: Reinette Chatre <reinette.chatre@intel.com> Link: https://lkml.kernel.org/r/387e78e444582403c2454479e576caf5721a363f.1506382469.git.tony.luck@intel.com
2017-08-01x86/intel_rdt: Show bitmask of shareable resource with other executing unitsFenghua Yu1-0/+7
CPUID.(EAX=0x10, ECX=res#):EBX[31:0] reports a bit mask for a resource. Each set bit within the length of the CBM indicates the corresponding unit of the resource allocation may be used by other entities in the platform (e.g. an integrated graphics engine or hardware units outside the processor core and have direct access to the resource). Each cleared bit within the length of the CBM indicates the corresponding allocation unit can be configured to implement a priority-based allocation scheme without interference with other hardware agents in the system. Bits outside the length of the CBM are reserved. More details on the bit mask are described in x86 Software Developer's Manual. The bitmask is shown in "info" directory for each resource. It's up to user to decide how to use the bitmask within a CBM in a partition to share or isolate a resource with other executing units. Suggested-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: ravi.v.shankar@intel.com Cc: peterz@infradead.org Cc: eranian@google.com Cc: ak@linux.intel.com Cc: davidcc@google.com Cc: vikas.shivappa@linux.intel.com Link: http://lkml.kernel.org/r/20170725223904.12996-1-tony.luck@intel.com
2017-08-01x86/intel_rdt/cqm: Documentation for resctrl based RDT MonitoringVikas Shivappa1-38/+278
Add a description of resctrl based RDT(resource director technology) monitoring extension and its usage. [Tony: Added descriptions for how monitoring and allocation are measured and some cleanups] Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: ravi.v.shankar@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 Cc: reinette.chatre@intel.com Link: http://lkml.kernel.org/r/1501017287-28083-3-git-send-email-vikas.shivappa@linux.intel.com
2017-05-09x86/intel_rdt: Fix a typo in DocumentationXiaochen Shen1-1/+1
Example 3 contains a typo: "C0" in "# echo C0 > p0/cpus" is wrong because it specifies core 6-7 instead of wanted core 4-7. Correct this typo to avoid confusion. Signed-off-by: Xiaochen Shen <xiaochen.shen@intel.com> Acked-by: Fenghua Yu <fenghua.yu@intel.com> Cc: vikas.shivappa@linux.intel.com Cc: tony.luck@intel.com Link: http://lkml.kernel.org/r/1493781356-24229-1-git-send-email-xiaochen.shen@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-14Documentation, x86: Intel Memory bandwidth allocationVikas Shivappa1-20/+87
Update the 'intel_rdt_ui' documentation to have Memory bandwidth(b/w) allocation interface usage. Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com> Cc: ravi.v.shankar@intel.com Cc: tony.luck@intel.com Cc: fenghua.yu@intel.com Cc: vikas.shivappa@intel.com Link: http://lkml.kernel.org/r/1491611637-20417-2-git-send-email-vikas.shivappa@linux.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-10x86/intel_rdt: Add cpus_list rdtgroup fileJiri Olsa1-0/+3
The resource control filesystem provides only a bitmask based cpus file for assigning CPUs to a resource group. That's cumbersome with large cpumasks and non-intuitive when modifying the file from the command line. Range based cpu lists are commonly used along with bitmask based cpu files in various subsystems throughout the kernel. Add 'cpus_list' file which is CPU range based. # cd /sys/fs/resctrl/ # echo 1-10 > krava/cpus_list # cat krava/cpus_list 1-10 # cat krava/cpus 0007fe # cat cpus fffff9 # cat cpus_list 0,3-23 [ tglx: Massaged changelog and replaced "bitmask lists" by "CPU ranges" ] Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Shaohua Li <shli@fb.com> Link: http://lkml.kernel.org/r/20170410145232.GF25354@krava Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2017-04-05x86/intel_rdt: Implement "update" mode when writing schemata fileTony Luck1-0/+14
The schemata file can have multiple lines and it is cumbersome to update all lines. Remove code that requires that the user provides values for every resource (in the right order). If the user provides values for just a few resources, update them and leave the rest unchanged. Side benefit: we now check which values were updated and only send IPIs to cpus that actually have updates. Signed-off-by: Tony Luck <tony.luck@intel.com> Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com> Tested-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com> Cc: ravi.v.shankar@intel.com Cc: fenghua.yu@intel.com Cc: peterz@infradead.org Cc: vikas.shivappa@intel.com Cc: h.peter.anvin@intel.com Link: http://lkml.kernel.org/r/1491255857-17213-3-git-send-email-vikas.shivappa@linux.intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-12-15Documentation, x86, resctrl: Recommend locking for resctrlfsMarcelo Tosatti1-0/+114
Concurrent write or read/write access from applications to the resctrlfs directory can result in incorrect readouts or setups. Recommend a standard locking scheme for applications to use. Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Link: http://lkml.kernel.org/r/20161214170835.GA16924@amt.cnet Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2016-11-07x86/intel_rdt: Add info files to DocumentationThomas Gleixner1-0/+19
The content of the directories and files in the info directory of the resctrl filesystem are not documented. Add the missing bits and pieces. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Shaohua Li <shli@fb.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Tony Luck <tony.luck@intel.com>
2016-10-30Documentation, x86: Documentation for Intel resource allocation user interfaceFenghua Yu1-0/+195
The documentation describes user interface of how to allocate resource in Intel RDT. Please note that the documentation covers generic user interface. Current patch set code only implemente CAT L3. CAT L2 code will be sent later. [ tglx: Added cpu example ] Signed-off-by: Fenghua Yu <fenghua.yu@intel.com> Cc: "Ravi V Shankar" <ravi.v.shankar@intel.com> Cc: "Tony Luck" <tony.luck@intel.com> Cc: "Shaohua Li" <shli@fb.com> Cc: "Sai Prakhya" <sai.praneeth.prakhya@intel.com> Cc: "Peter Zijlstra" <peterz@infradead.org> Cc: "Stephane Eranian" <eranian@google.com> Cc: "Dave Hansen" <dave.hansen@intel.com> Cc: "David Carrillo-Cisneros" <davidcc@google.com> Cc: "Nilay Vaish" <nilayvaish@gmail.com> Cc: "Vikas Shivappa" <vikas.shivappa@linux.intel.com> Cc: "Ingo Molnar" <mingo@elte.hu> Cc: "Borislav Petkov" <bp@suse.de> Cc: "H. Peter Anvin" <h.peter.anvin@intel.com> Link: http://lkml.kernel.org/r/1477692289-37412-2-git-send-email-fenghua.yu@intel.com Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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