summaryrefslogtreecommitdiff
path: root/tools/include/asm/barrier.h
AgeCommit message (Collapse)AuthorFilesLines
2018-11-06nds32: Perf portingNickhu1-0/+2
This is the commit that porting the perf for nds32. 1.Raw event: The raw events start with 'r'. Usage: perf stat -e rXYZ ./app X: the index of performance counter. YZ: the index(convert to hexdecimal) of events Example: 'perf stat -e r101 ./app' means the counter 1 will count the instruction event. The index of counter and events can be found in "Andes System Privilege Architecture Version 3 Manual". Or you can perform the 'perf list' to find the symbolic name of raw events. 2.Perf mmap2: Fix unexpected perf mmap2() page fault When the mmap2() called by perf application, you will encounter such condition:"failed to write." With return value -EFAULT This is due to the page fault caused by "reading" buffer from the mapped legal address region to write to the descriptor. The page_fault handler will get a VM_FAULT_SIGBUS return value, which should not happens here.(Due to this is a read request.) You can refer to kernel/events/core.c:perf_mmap_fault(...) If "(vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))" is evaluated as true, you will get VM_FAULT_SIGBUS as return value. However, this is not an write request. The flags which indicated why the page fault happens is wrong. Furthermore, NDS32 SPAv3 is not able to detect it is read or write. It only know either it is instruction fetch or data access. Therefore, by removing the wrong flag assignment(actually, the hardware is not able to show the reason), we can fix this bug. 3.Perf multiple events map to same counter. When there are multiple events map to the same counter, the counter counts inaccurately. This is because each counter only counts one event in the same time. So when there are multiple events map to same counter, they have to take turns in each context. There are two solution: 1. Print the error message when multiple events map to the same counter. But print the error message would let the program hang in loop. The ltp (linux test program) would be failed when the program hang in loop. 2. Don't print the error message, the ltp would pass. But the user need to have the knowledge that don't count the events which map to the same counter, or the user will get the inaccurate results. We choose method 2 for the solution Signed-off-by: Nickhu <nickhu@andestech.com> Acked-by: Greentime Hu <greentime@andestech.com> Signed-off-by: Greentime Hu <greentime@andestech.com>
2018-10-19tools, perf: add and use optimized ring_buffer_{read_head, write_tail} helpersDaniel Borkmann1-0/+35
Currently, on x86-64, perf uses LFENCE and MFENCE (rmb() and mb(), respectively) when processing events from the perf ring buffer which is unnecessarily expensive as we can do more lightweight in particular given this is critical fast-path in perf. According to Peter rmb()/mb() were added back then via a94d342b9cb0 ("tools/perf: Add required memory barriers") at a time where kernel still supported chips that needed it, but nowadays support for these has been ditched completely, therefore we can fix them up as well. While for x86-64, replacing rmb() and mb() with smp_*() variants would result in just a compiler barrier for the former and LOCK + ADD for the latter (__sync_synchronize() uses slower MFENCE by the way), Peter suggested we can use smp_{load_acquire,store_release}() instead for architectures where its implementation doesn't resolve in slower smp_mb(). Thus, e.g. in x86-64 we would be able to avoid CPU barrier entirely due to TSO. For architectures where the latter needs to use smp_mb() e.g. on arm, we stick to cheaper smp_rmb() variant for fetching the head. This work adds helpers ring_buffer_read_head() and ring_buffer_write_tail() for tools infrastructure that either switches to smp_load_acquire() for architectures where it is cheaper or uses READ_ONCE() + smp_rmb() barrier for those where it's not in order to fetch the data_head from the perf control page, and it uses smp_store_release() to write the data_tail. Latter is smp_mb() + WRITE_ONCE() combination or a cheaper variant if architecture allows for it. Those that rely on smp_rmb() and smp_mb() can further improve performance in a follow up step by implementing the two under tools/arch/*/include/asm/barrier.h such that they don't have to fallback to rmb() and mb() in tools/include/asm/barrier.h. Switch perf to use ring_buffer_read_head() and ring_buffer_write_tail() so it can make use of the optimizations. Later, we convert libbpf as well to use the same helpers. Side note [0]: the topic has been raised of whether one could simply use the C11 gcc builtins [1] for the smp_load_acquire() and smp_store_release() instead: __atomic_load_n(ptr, __ATOMIC_ACQUIRE); __atomic_store_n(ptr, val, __ATOMIC_RELEASE); Kernel and (presumably) tooling shipped along with the kernel has a minimum requirement of being able to build with gcc-4.6 and the latter does not have C11 builtins. While generally the C11 memory models don't align with the kernel's, the C11 load-acquire and store-release alone /could/ suffice, however. Issue is that this is implementation dependent on how the load-acquire and store-release is done by the compiler and the mapping of supported compilers must align to be compatible with the kernel's implementation, and thus needs to be verified/tracked on a case by case basis whether they match (unless an architecture uses them also from kernel side). The implementations for smp_load_acquire() and smp_store_release() in this patch have been adapted from the kernel side ones to have a concrete and compatible mapping in place. [0] http://patchwork.ozlabs.org/patch/985422/ [1] https://gcc.gnu.org/onlinedocs/gcc/_005f_005fatomic-Builtins.html Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Will Deacon <will.deacon@arm.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2017-11-02License cleanup: add SPDX GPL-2.0 license identifier to files with no licenseGreg Kroah-Hartman1-0/+1
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 <kstewart@linuxfoundation.org> Reviewed-by: Philippe Ombredanne <pombredanne@nexb.com> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-08perf tools: Move generic barriers out of perf-sys.hArnaldo Carvalho de Melo1-0/+2
We will need it for atomic.h, so move it from the ad-hoc tools/perf/ place to a tools/ subset of the kernel arch/ hierarchy. The parisc stuff was just using the asm-generic/barrier.h, no need to introduce a tools/arch/parisc/ tree just yet. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-tfas9bs1gje0hfsvhqgrosd6@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-08perf tools: Move tile barrier.h stuff to tools/arch/tile/include/asm/barrier.hArnaldo Carvalho de Melo1-0/+2
We will need it for atomic.h, so move it from the ad-hoc tools/perf/ place to a tools/ subset of the kernel arch/ hierarchy. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-jwcs4r1lo0ld8a4ricbe0zug@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-08perf tools: Move mips barrier.h stuff to tools/arch/mips/include/asm/barrier.hArnaldo Carvalho de Melo1-0/+2
We will need it for atomic.h, so move it from the ad-hoc tools/perf/ place to a tools/ subset of the kernel arch/ hierarchy. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Deng-Cheng Zhu <dengcheng.zhu@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-c5a8m8lbjuy0agep6giykxbz@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-08perf tools: Move xtensa barrier.h stuff to ↵Arnaldo Carvalho de Melo1-0/+2
tools/arch/xtensa/include/asm/barrier.h We will need it for atomic.h, so move it from the ad-hoc tools/perf/ place to a tools/ subset of the kernel arch/ hierarchy. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-lp68dspbtjcwbpzd7x5c6zp5@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-08perf tools: Move arm(64) barrier.h stuff to ↵Arnaldo Carvalho de Melo1-0/+4
tools/arch/arm*/include/asm/barrier.h We will need it for atomic.h, so move it from the ad-hoc tools/perf/ place to a tools/ subset of the kernel arch/ hierarchy. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-cgfhreaejd7ohitdjccu9k2o@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-08perf tools: Move ia64 barrier.h stuff to tools/arch/ia64/include/asm/barrier.hArnaldo Carvalho de Melo1-0/+2
We will need it for atomic.h, so move it from the ad-hoc tools/perf/ place to a tools/ subset of the kernel arch/ hierarchy. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-4op0qdukegrdumyefz4icxk0@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-08perf tools: Move alpha barrier.h stuff to tools/arch/alpha/include/asm/barrier.hArnaldo Carvalho de Melo1-0/+2
We will need it for atomic.h, so move it from the ad-hoc tools/perf/ place to a tools/ subset of the kernel arch/ hierarchy. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-vs2plxuph0ne3zcupijgjy9z@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-08perf tools: Move sparc barrier.h stuff to tools/arch/sparc/include/asm/barrier.hArnaldo Carvalho de Melo1-0/+2
We will need it for atomic.h, so move it from the ad-hoc tools/perf/ place to a tools/ subset of the kernel arch/ hierarchy. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-f0d04b9x63grt30nahpw9ei0@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-08perf tools: Move sh barrier.h stuff to tools/arch/sh/include/asm/barrier.hArnaldo Carvalho de Melo1-0/+2
We will need it for atomic.h, so move it from the ad-hoc tools/perf/ place to a tools/ subset of the kernel arch/ hierarchy. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-6xqb97k782wqp1r3v6jqayki@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-08perf tools: Move s390 barrier.h stuff to tools/arch/s390/include/asm/barrier.hArnaldo Carvalho de Melo1-0/+2
We will need it for atomic.h, so move it from the ad-hoc tools/perf/ place to a tools/ subset of the kernel arch/ hierarchy. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-zv4x77074resrkl4ayzf5e7d@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-08perf tools: Move powerpc barrier.h stuff to ↵Arnaldo Carvalho de Melo1-0/+2
tools/arch/powerpc/include/asm/barrier.h We will need it for atomic.h, so move it from the ad-hoc tools/perf/ place to a tools/ subset of the kernel arch/ hierarchy. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-pk6f5x9vh8k2ebzhh9uj5wo2@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2015-05-08perf tools: Move x86 barrier.h stuff to tools/arch/x86/include/asm/barrier.hArnaldo Carvalho de Melo1-0/+3
We will need it for atomic.h, so move it from the ad-hoc tools/perf/ place to a tools/ subset of the kernel arch/ hierarchy. Other aches will follow, each in a cset. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Borislav Petkov <bp@suse.de> Cc: David Ahern <dsahern@gmail.com> Cc: Don Zickus <dzickus@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-vy6bqmsvm6puibpay2cy4wid@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>