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authorLinus Torvalds <torvalds@linux-foundation.org>2016-12-12 11:46:21 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-12-12 11:46:21 -0800
commitbca13ce4554ae9cf5083e5adf395ad2266cb571b (patch)
treede392199f8eecd9c1331e2bcff5b60d4f188a5db /drivers
parent0719dbf5e1e802f1bcd0b8d8fc7639d5d1584d48 (diff)
parentb0c1ef52959582144bbea9a2b37db7f4c9e399f7 (diff)
downloadlinux-bca13ce4554ae9cf5083e5adf395ad2266cb571b.tar.bz2
Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull perf updates from Ingo Molnar: "This update is pretty big and almost exclusively includes tooling changes, because v4.9's LTS status forced to completion most of the pending kernel side hardware enablement work and because we tried to freeze core perf work a bit to give a time window for the fuzzing efforts. The diff is large mostly due to the JSON hardware event tables added for Intel and Power8 CPUs. This was a popular feature request from people working close to hardware and from the HPC community. Tree size is big because this added the CPU event tables for over a decade of Intel CPUs. Future changes for a CPU vendor alrady support should be much smaller, as events for new models are added. The new events are listed in 'perf list', for the CPU model the tool is running on. If you find an interesting event it can be used as-is: $ perf stat -a -e l2_lines_out.pf_clean sleep 1 Performance counter stats for 'system wide': 7,860,403 l2_lines_out.pf_clean 1.000624918 seconds time elapsed The event lists can be searched the usual 'perf list' fashion for (case insensitive) substrings as well: $ perf list l2_lines_out List of pre-defined events (to be used in -e): cache: l2_lines_out.demand_clean [Clean L2 cache lines evicted by demand] l2_lines_out.demand_dirty [Dirty L2 cache lines evicted by demand] l2_lines_out.dirty_all [Dirty L2 cache lines filling the L2] l2_lines_out.pf_clean [Clean L2 cache lines evicted by L2 prefetch] l2_lines_out.pf_dirty [Dirty L2 cache lines evicted by L2 prefetch] etc. There's a few high level categories as well that can be listed: 'cache', 'floating point', 'frontend', 'memory', 'pipeline', 'virtual memory'. Existing generic events and workflows should work as-is. The only kernel side change is a late breaking fix for an older regression, related to Intel BTS, LBR and PT feature interaction. On the tooling side there are three new tools / major features: - The new 'perf c2c' tool provides means for Shared Data C2C/HITM analysis. This allows you to track down cacheline contention. The tool is based on x86's load latency and precise store facility events provided by Intel CPUs. It was tested by Joe Mario and has proven to be useful, finding some cacheline contentions. Joe also wrote a blog about c2c tool with examples: https://joemario.github.io/blog/2016/09/01/c2c-blog/ excerpt of the content on this site: At a high level, “perf c2c” will show you: * The cachelines where false sharing was detected. * The readers and writers to those cachelines, and the offsets where those accesses occurred. * The pid, tid, instruction addr, function name, binary object name for those readers and writers. * The source file and line number for each reader and writer. * The average load latency for the loads to those cachelines. * Which numa nodes the samples a cacheline came from and which CPUs were involved. Using perf c2c is similar to using the Linux perf tool today. First collect data with “perf c2c record”, then generate a report output with “perf c2c report” There one finds extensive details on using the tool, with tips on reducing the volume of samples while still capturing enough to do its job. (Dick Fowles, Joe Mario, Don Zickus, Jiri Olsa) - The new 'perf sched timehist' tool provides tailored analysis of scheduling events. Example usage: perf sched record -- sleep 1 perf sched timehist By default it shows the individual schedule events, including the wait time (time between sched-out and next sched-in events for the task), the task scheduling delay (time between wakeup and actually running) and run time for the task: time cpu task name wait time sch delay run time [tid/pid] (msec) (msec) (msec) -------- ------ ---------------- --------- --------- -------- 1.874569 [0011] gcc[31949] 0.014 0.000 1.148 1.874591 [0010] gcc[31951] 0.000 0.000 0.024 1.874603 [0010] migration/10[59] 3.350 0.004 0.011 1.874604 [0011] <idle> 1.148 0.000 0.035 1.874723 [0005] <idle> 0.016 0.000 1.383 1.874746 [0005] gcc[31949] 0.153 0.078 0.022 ... Times are in msec.usec. (David Ahern, Namhyung Kim) - Add CPU vendor hardware event tables: Add JSON files with vendor event naming for Intel and Power8 processors, allowing users of tools like oprofile to keep using the event names they are used to, as well as people reading vendor documentation, where such naming is used. (Andi Kleen, Sukadev Bhattiprolu) You should see all the new events with 'perf list' and you should be able to search them, for example 'perf list miss' will list all the myriads of miss events. Other tooling features added were: - Cross-arch annotation support: o Improve ARM support in the annotation code, affecting 'perf annotate', 'perf report' and live annotation in 'perf top' (Kim Phillips) o Initial support for PowerPC in the annotation code (Ravi Bangoria) o Support AArch64 in the 'annotate' code, native/local and cross-arch/remote (Kim Phillips) - Allow considering just events in a given time interval, via the '--time start.s.ms,end.s.ms' command line, added to 'perf kmem', 'perf report', 'perf sched timehist' and 'perf script' (David Ahern) - Add option to stop printing a callchain at one of a given group of symbol names (David Ahern) - Track memory freed in 'perf kmem stat' (David Ahern) - Allow querying and setting .perfconfig variables (Taeung Song) - Show branch information in callchains (predicted, TSX aborts, loop iteractions, etc) (Jin Yao) - Dynamicly change verbosity level by pressing 'V' in the 'perf top/report' hists TUI browser (Alexis Berlemont) - Implement 'perf trace --delay' in the same fashion as in 'perf record --delay', to skip sampling workload initialization events (Alexis Berlemont) - Make vendor named events case insensitive in 'perf list', i.e. 'perf list LONGEST_LAT' works just the same as 'perf list longest_lat' (Andi Kleen) - Add unwinding support for jitdump (Stefano Sanfilippo) Tooling infrastructure changes: - Support linking perf with clang and LLVM libraries, initially statically, but this limitation will be lifted and shared libraries, when available, will be preferred to the static build, that should, as with other features, be enabled explicitly (Wang Nan) - Add initial support (and perf test entry) for tooling hooks, starting with 'record_start' and 'record_end', that will have as its initial user the eBPF infrastructure, where perf_ prefixed functions will be JITed and run when such hooks are called (Wang Nan) - Implement assorted libbpf improvements (Wang Nan)" ... and lots of other changes, features, cleanups and refactorings I did not list, see the shortlog and the git log for details" * 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (220 commits) perf/x86: Fix exclusion of BTS and LBR for Goldmont perf tools: Explicitly document that --children is enabled by default perf sched timehist: Cleanup idle_max_cpu handling perf sched timehist: Handle zero sample->tid properly perf callchain: Introduce callchain_cursor__copy() perf sched: Cleanup option processing perf sched timehist: Improve error message when analyzing wrong file perf tools: Move perf build related variables under non fixdep leg perf tools: Force fixdep compilation at the start of the build perf tools: Move PERF-VERSION-FILE target into rules area perf build: Check LLVM version in feature check perf annotate: Show raw form for jump instruction with indirect target perf tools: Add non config targets perf tools: Cleanup build directory before each test perf tools: Move python/perf.so target into rules area perf tools: Move install-gtk target into rules area tools build: Move tabs to spaces where suitable tools build: Make the .cmd file more readable perf clang: Compile BPF script using builtin clang support perf clang: Support compile IR to BPF object and add testcase ...
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