Eric Lee / smarc-fsl-linux-kernel

02 Nov, 2017

1 commit

  • b24413180   License cleanup: add SPDX GPL-2.0 license identifier to files with no license ... Browse Code »

    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
    Reviewed-by: Philippe Ombredanne
    Reviewed-by: Thomas Gleixner
    Signed-off-by: Greg Kroah-Hartman

    Greg Kroah-Hartman
     

09 Feb, 2016

1 commit

  • cb2517653   sched/debug: Make schedstats a runtime tunable that is disabled by default ... Browse Code »

    schedstats is very useful during debugging and performance tuning but it
    incurs overhead to calculate the stats. As such, even though it can be
    disabled at build time, it is often enabled as the information is useful.

    This patch adds a kernel command-line and sysctl tunable to enable or
    disable schedstats on demand (when it's built in). It is disabled
    by default as someone who knows they need it can also learn to enable
    it when necessary.

    The benefits are dependent on how scheduler-intensive the workload is.
    If it is then the patch reduces the number of cycles spent calculating
    the stats with a small benefit from reducing the cache footprint of the
    scheduler.

    These measurements were taken from a 48-core 2-socket
    machine with Xeon(R) E5-2670 v3 cpus although they were also tested on a
    single socket machine 8-core machine with Intel i7-3770 processors.

    netperf-tcp
    4.5.0-rc1 4.5.0-rc1
    vanilla nostats-v3r1
    Hmean 64 560.45 ( 0.00%) 575.98 ( 2.77%)
    Hmean 128 766.66 ( 0.00%) 795.79 ( 3.80%)
    Hmean 256 950.51 ( 0.00%) 981.50 ( 3.26%)
    Hmean 1024 1433.25 ( 0.00%) 1466.51 ( 2.32%)
    Hmean 2048 2810.54 ( 0.00%) 2879.75 ( 2.46%)
    Hmean 3312 4618.18 ( 0.00%) 4682.09 ( 1.38%)
    Hmean 4096 5306.42 ( 0.00%) 5346.39 ( 0.75%)
    Hmean 8192 10581.44 ( 0.00%) 10698.15 ( 1.10%)
    Hmean 16384 18857.70 ( 0.00%) 18937.61 ( 0.42%)

    Small gains here, UDP_STREAM showed nothing intresting and neither did
    the TCP_RR tests. The gains on the 8-core machine were very similar.

    tbench4
    4.5.0-rc1 4.5.0-rc1
    vanilla nostats-v3r1
    Hmean mb/sec-1 500.85 ( 0.00%) 522.43 ( 4.31%)
    Hmean mb/sec-2 984.66 ( 0.00%) 1018.19 ( 3.41%)
    Hmean mb/sec-4 1827.91 ( 0.00%) 1847.78 ( 1.09%)
    Hmean mb/sec-8 3561.36 ( 0.00%) 3611.28 ( 1.40%)
    Hmean mb/sec-16 5824.52 ( 0.00%) 5929.03 ( 1.79%)
    Hmean mb/sec-32 10943.10 ( 0.00%) 10802.83 ( -1.28%)
    Hmean mb/sec-64 15950.81 ( 0.00%) 16211.31 ( 1.63%)
    Hmean mb/sec-128 15302.17 ( 0.00%) 15445.11 ( 0.93%)
    Hmean mb/sec-256 14866.18 ( 0.00%) 15088.73 ( 1.50%)
    Hmean mb/sec-512 15223.31 ( 0.00%) 15373.69 ( 0.99%)
    Hmean mb/sec-1024 14574.25 ( 0.00%) 14598.02 ( 0.16%)
    Hmean mb/sec-2048 13569.02 ( 0.00%) 13733.86 ( 1.21%)
    Hmean mb/sec-3072 12865.98 ( 0.00%) 13209.23 ( 2.67%)

    Small gains of 2-4% at low thread counts and otherwise flat. The
    gains on the 8-core machine were slightly different

    tbench4 on 8-core i7-3770 single socket machine
    Hmean mb/sec-1 442.59 ( 0.00%) 448.73 ( 1.39%)
    Hmean mb/sec-2 796.68 ( 0.00%) 794.39 ( -0.29%)
    Hmean mb/sec-4 1322.52 ( 0.00%) 1343.66 ( 1.60%)
    Hmean mb/sec-8 2611.65 ( 0.00%) 2694.86 ( 3.19%)
    Hmean mb/sec-16 2537.07 ( 0.00%) 2609.34 ( 2.85%)
    Hmean mb/sec-32 2506.02 ( 0.00%) 2578.18 ( 2.88%)
    Hmean mb/sec-64 2511.06 ( 0.00%) 2569.16 ( 2.31%)
    Hmean mb/sec-128 2313.38 ( 0.00%) 2395.50 ( 3.55%)
    Hmean mb/sec-256 2110.04 ( 0.00%) 2177.45 ( 3.19%)
    Hmean mb/sec-512 2072.51 ( 0.00%) 2053.97 ( -0.89%)

    In constract, this shows a relatively steady 2-3% gain at higher thread
    counts. Due to the nature of the patch and the type of workload, it's
    not a surprise that the result will depend on the CPU used.

    hackbench-pipes
    4.5.0-rc1 4.5.0-rc1
    vanilla nostats-v3r1
    Amean 1 0.0637 ( 0.00%) 0.0660 ( -3.59%)
    Amean 4 0.1229 ( 0.00%) 0.1181 ( 3.84%)
    Amean 7 0.1921 ( 0.00%) 0.1911 ( 0.52%)
    Amean 12 0.3117 ( 0.00%) 0.2923 ( 6.23%)
    Amean 21 0.4050 ( 0.00%) 0.3899 ( 3.74%)
    Amean 30 0.4586 ( 0.00%) 0.4433 ( 3.33%)
    Amean 48 0.5910 ( 0.00%) 0.5694 ( 3.65%)
    Amean 79 0.8663 ( 0.00%) 0.8626 ( 0.43%)
    Amean 110 1.1543 ( 0.00%) 1.1517 ( 0.22%)
    Amean 141 1.4457 ( 0.00%) 1.4290 ( 1.16%)
    Amean 172 1.7090 ( 0.00%) 1.6924 ( 0.97%)
    Amean 192 1.9126 ( 0.00%) 1.9089 ( 0.19%)

    Some small gains and losses and while the variance data is not included,
    it's close to the noise. The UMA machine did not show anything particularly
    different

    pipetest
    4.5.0-rc1 4.5.0-rc1
    vanilla nostats-v2r2
    Min Time 4.13 ( 0.00%) 3.99 ( 3.39%)
    1st-qrtle Time 4.38 ( 0.00%) 4.27 ( 2.51%)
    2nd-qrtle Time 4.46 ( 0.00%) 4.39 ( 1.57%)
    3rd-qrtle Time 4.56 ( 0.00%) 4.51 ( 1.10%)
    Max-90% Time 4.67 ( 0.00%) 4.60 ( 1.50%)
    Max-93% Time 4.71 ( 0.00%) 4.65 ( 1.27%)
    Max-95% Time 4.74 ( 0.00%) 4.71 ( 0.63%)
    Max-99% Time 4.88 ( 0.00%) 4.79 ( 1.84%)
    Max Time 4.93 ( 0.00%) 4.83 ( 2.03%)
    Mean Time 4.48 ( 0.00%) 4.39 ( 1.91%)
    Best99%Mean Time 4.47 ( 0.00%) 4.39 ( 1.91%)
    Best95%Mean Time 4.46 ( 0.00%) 4.38 ( 1.93%)
    Best90%Mean Time 4.45 ( 0.00%) 4.36 ( 1.98%)
    Best50%Mean Time 4.36 ( 0.00%) 4.25 ( 2.49%)
    Best10%Mean Time 4.23 ( 0.00%) 4.10 ( 3.13%)
    Best5%Mean Time 4.19 ( 0.00%) 4.06 ( 3.20%)
    Best1%Mean Time 4.13 ( 0.00%) 4.00 ( 3.39%)

    Small improvement and similar gains were seen on the UMA machine.

    The gain is small but it stands to reason that doing less work in the
    scheduler is a good thing. The downside is that the lack of schedstats and
    tracepoints may be surprising to experts doing performance analysis until
    they find the existence of the schedstats= parameter or schedstats sysctl.
    It will be automatically activated for latencytop and sleep profiling to
    alleviate the problem. For tracepoints, there is a simple warning as it's
    not safe to activate schedstats in the context when it's known the tracepoint
    may be wanted but is unavailable.

    Signed-off-by: Mel Gorman
    Reviewed-by: Matt Fleming
    Reviewed-by: Srikar Dronamraju
    Cc: Linus Torvalds
    Cc: Mike Galbraith
    Cc: Peter Zijlstra
    Cc: Thomas Gleixner
    Link: http://lkml.kernel.org/r/1454663316-22048-1-git-send-email-mgorman@techsingularity.net
    Signed-off-by: Ingo Molnar

    Mel Gorman
     

17 Nov, 2011

1 commit

  • 029632fbb   sched: Make separate sched*.c translation units ... Browse Code »
    43

    Since once needs to do something at conferences and fixing compile
    warnings doesn't actually require much if any attention I decided
    to break up the sched.c #include "*.c" fest.

    This further modularizes the scheduler code.

    Signed-off-by: Peter Zijlstra
    Link: http://lkml.kernel.org/n/tip-x0fcd3mnp8f9c99grcpewmhi@git.kernel.org
    Signed-off-by: Ingo Molnar

    Peter Zijlstra
     

11 Feb, 2009

1 commit

  • ad0b0fd55   sched, latencytop: incorporate review feedback from Andrew Morton ... Browse Code »

    Andrew had some suggestions for the latencytop file; this patch takes care
    of most of these:

    * Add documentation
    * Turn account_scheduler_latency into an inline function
    * Don't report negative values to userspace
    * Make the file operations struct const
    * Fix a few checkpatch.pl warnings

    Signed-off-by: Arjan van de Ven
    Signed-off-by: Andrew Morton
    Signed-off-by: Ingo Molnar

    Arjan van de Ven
     

26 Jan, 2008

1 commit