kernel/tools/perf/bench/bench.h, branch linux-4.17.y

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

perf tools: Remove unused 'prefix' from builtin functions

2017-03-27T14:58:09Z

We got it from the git sources but never used it for anything, with the place where this would be somehow used remaining: static int run_builtin(struct cmd_struct *p, int argc, const char **argv) { prefix = NULL; if (p->option & RUN_SETUP) prefix = NULL; /* setup_perf_directory(); */ Ditch it. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-uw5swz05vol0qpr32c5lpvus@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Remove needless 'extern' from function prototypes

2016-03-23T18:06:35Z

Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-w246stf7ponfamclsai6b9zo@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Remove misplaced __maybe_unused

2016-03-23T15:03:04Z

All over the tree. Cc: David Ahern cc: Jiri Olsa Cc: Namhyung Kim Cc: Ravi Bangoria Link: http://lkml.kernel.org/n/tip-8nzhnokxyp8y4v7gf0j00oyb@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf bench futex: Add lock_pi stresser

2015-07-20T20:49:51Z

Allows a way of measuring low level kernel implementation of FUTEX_LOCK_PI and FUTEX_UNLOCK_PI. The program comes in two flavors: (i) single futex (default), all threads contend on the same uaddr. For the sake of the benchmark, we call into kernel space even when the lock is uncontended. The kernel will set it to TID, any waters that come in and contend for the pi futex will be handled respectively by the kernel. (ii) -M option for multiple futexes, each thread deals with its own futex. This is a trivial scenario and only measures kernel handling of 0->TID transition. Signed-off-by: Davidlohr Bueso Cc: Mel Gorman Link: http://lkml.kernel.org/r/1436259353.12255.78.camel@stgolabs.net Signed-off-by: Arnaldo Carvalho de Melo

perf bench futex: Support parallel waker threads

2015-05-08T19:23:50Z

The futex-wake benchmark only measures wakeups done within a single process. While this has value in its own, it does not really generate any hb->lock contention. A new benchmark 'wake-parallel' is added, by extending the futex-wake code such that we can measure parallel waker threads. The program output shows the avg per-thread latency in order to complete its share of wakeups: Run summary [PID 13474]: blocking on 512 threads (at [private] futex 0xa88668), 8 threads waking up 64 at a time. [Run 1]: Avg per-thread latency (waking 64/512 threads) in 0.6230 ms (+-15.31%) [Run 2]: Avg per-thread latency (waking 64/512 threads) in 0.5175 ms (+-29.95%) [Run 3]: Avg per-thread latency (waking 64/512 threads) in 0.7578 ms (+-18.03%) [Run 4]: Avg per-thread latency (waking 64/512 threads) in 0.8944 ms (+-12.54%) [Run 5]: Avg per-thread latency (waking 64/512 threads) in 1.1204 ms (+-23.85%) Avg per-thread latency (waking 64/512 threads) in 0.7826 ms (+-9.91%) Naturally, different combinations of numbers of blocking and waker threads will exhibit different information. Signed-off-by: Davidlohr Bueso Tested-by: Arnaldo Carvalho de Melo Cc: Davidlohr Bueso Link: http://lkml.kernel.org/r/1431110280-20231-1-git-send-email-dave@stgolabs.net Signed-off-by: Arnaldo Carvalho de Melo

perf bench: Add --repeat option

2014-06-19T19:13:15Z

There are a number of benchmarks that do single runs and as a result does not really help users gain a general idea of how the workload performs. So the user must either manually do multiple runs or just use single bogus results. This option will enable users to specify the amount of runs (arbitrarily defaulted to 10, to use the existing benchmarks default) through the '--repeat' option. Add it to perf-bench instead of implementing it always in each specific benchmark. Signed-off-by: Davidlohr Bueso Cc: Aswin Chandramouleeswaran Cc: Hitoshi Mitake Cc: Jiri Olsa Link: http://lkml.kernel.org/r/1402942467-10671-2-git-send-email-davidlohr@hp.com [ Kept the existing default of 10, changing it to something else should be done on separate patch ] Signed-off-by: Arnaldo Carvalho de Melo

perf bench: Add futex-requeue microbenchmark

2014-03-14T14:20:44Z

Block a bunch of threads on a futex and requeue them on another, N at a time. This program is particularly useful to measure the latency of nthread requeues without waking up any tasks -- thus mimicking a regular futex_wait. An example run: $ perf bench futex requeue -r 100 -t 64 Run summary [PID 151011]: Requeuing 64 threads (from 0x7d15c4 to 0x7d15c8), 1 at a time. [Run 1]: Requeued 64 of 64 threads in 0.0400 ms [Run 2]: Requeued 64 of 64 threads in 0.0390 ms [Run 3]: Requeued 64 of 64 threads in 0.0400 ms ... [Run 100]: Requeued 64 of 64 threads in 0.0390 ms Requeued 64 of 64 threads in 0.0399 ms (+-0.37%) Signed-off-by: Davidlohr Bueso Acked-by: Darren Hart Cc: Aswin Chandramouleeswaran Cc: Darren Hart Cc: Ingo Molnar Cc: Jason Low Cc: Peter Zijlstra Cc: Scott J Norton Cc: Thomas Gleixner Cc: Waiman Long Link: http://lkml.kernel.org/r/1387081917-9102-4-git-send-email-davidlohr@hp.com Signed-off-by: Arnaldo Carvalho de Melo

perf bench: Add futex-wake microbenchmark

2014-03-14T14:20:43Z

Block a bunch of threads on a futex and wake them up, N at a time. This program is particularly useful to measure the latency of nthread wakeups in non-error situations: all waiters are queued and all wake calls wakeup one or more tasks. An example run: $ perf bench futex wake -t 512 -r 100 Run summary [PID 27823]: blocking on 512 threads (at futex 0x7e10d4), waking up 1 at a time. [Run 1]: Wokeup 512 of 512 threads in 6.0080 ms [Run 2]: Wokeup 512 of 512 threads in 5.2280 ms [Run 3]: Wokeup 512 of 512 threads in 4.8300 ms ... [Run 100]: Wokeup 512 of 512 threads in 5.0100 ms Wokeup 512 of 512 threads in 5.0109 ms (+-2.25%) Signed-off-by: Davidlohr Bueso Acked-by: Darren Hart Cc: Aswin Chandramouleeswaran Cc: Darren Hart Cc: Ingo Molnar Cc: Jason Low Cc: Peter Zijlstra Cc: Scott J Norton Cc: Thomas Gleixner Cc: Waiman Long Link: http://lkml.kernel.org/r/1387081917-9102-3-git-send-email-davidlohr@hp.com Signed-off-by: Arnaldo Carvalho de Melo

perf bench: Add futex-hash microbenchmark

2014-03-14T14:20:43Z

Introduce futexes to perf-bench and add a program that stresses and measures the kernel's implementation of the hash table. This is a multi-threaded program that simply measures the amount of failed futex wait calls - we only want to deal with the hashing overhead, so a negative return of futex_wait_setup() is enough to do the trick. An example run: $ perf bench futex hash -t 32 Run summary [PID 10989]: 32 threads, each operating on 1024 [private] futexes for 10 secs. [thread 0] futexes: 0x19d9b10 ... 0x19dab0c [ 418713 ops/sec ] [thread 1] futexes: 0x19daca0 ... 0x19dbc9c [ 469913 ops/sec ] [thread 2] futexes: 0x19dbe30 ... 0x19dce2c [ 479744 ops/sec ] ... [thread 31] futexes: 0x19fbb80 ... 0x19fcb7c [ 464179 ops/sec ] Averaged 454310 operations/sec (+- 0.84%), total secs = 10 Signed-off-by: Davidlohr Bueso Acked-by: Darren Hart Cc: Aswin Chandramouleeswaran Cc: Darren Hart Cc: Ingo Molnar Cc: Jason Low Cc: Peter Zijlstra Cc: Scott J Norton Cc: Thomas Gleixner Cc: Waiman Long Link: http://lkml.kernel.org/r/1387081917-9102-2-git-send-email-davidlohr@hp.com Signed-off-by: Arnaldo Carvalho de Melo