Eric Lee / smarc-fsl-linux-kernel

02 Mar, 2017

2 commits

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
     

05 Jun, 2014

1 commit

31 Oct, 2011

1 commit

  • 9984de1a5   kernel: Map most files to use export.h instead of module.h ... Browse Code »

    The changed files were only including linux/module.h for the
    EXPORT_SYMBOL infrastructure, and nothing else. Revector them
    onto the isolated export header for faster compile times.

    Nothing to see here but a whole lot of instances of:

    -#include
    +#include

    This commit is only changing the kernel dir; next targets
    will probably be mm, fs, the arch dirs, etc.

    Signed-off-by: Paul Gortmaker

    Paul Gortmaker
     

13 Sep, 2011

1 commit

  • 757455d41   locking, latencytop: Annotate latency_lock as raw ... Browse Code »

    The latency_lock is lock can be taken in the guts of the
    scheduler code and therefore cannot be preempted on -rt -
    annotate it.

    In mainline this change documents the low level nature of
    the lock - otherwise there's no functional difference. Lockdep
    and Sparse checking will work as usual.

    Signed-off-by: Thomas Gleixner
    Signed-off-by: Ingo Molnar

    Thomas Gleixner
     

31 Mar, 2011

1 commit

14 Jan, 2011

1 commit

12 Nov, 2010

1 commit

  • 38715258a   latencytop: fix per task accumulator ... Browse Code »

    Per task latencytop accumulator prematurely terminates due to erroneous
    placement of latency_record_count. It should be incremented whenever a
    new record is allocated instead of increment on every latencytop event.

    Also fix search iterator to only search known record events instead of
    blindly searching all pre-allocated space.

    Signed-off-by: Ken Chen
    Reviewed-by: Arjan van de Ven
    Cc:
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Ken Chen
     

30 Mar, 2010

1 commit

  • 5a0e3ad6a   include cleanup: Update gfp.h and slab.h includes to prepare for breaking implic… ... Browse Code »

    …it slab.h inclusion from percpu.h

    percpu.h is included by sched.h and module.h and thus ends up being
    included when building most .c files. percpu.h includes slab.h which
    in turn includes gfp.h making everything defined by the two files
    universally available and complicating inclusion dependencies.

    percpu.h -> slab.h dependency is about to be removed. Prepare for
    this change by updating users of gfp and slab facilities include those
    headers directly instead of assuming availability. As this conversion
    needs to touch large number of source files, the following script is
    used as the basis of conversion.

    http://userweb.kernel.org/~tj/misc/slabh-sweep.py

    The script does the followings.

    * Scan files for gfp and slab usages and update includes such that
    only the necessary includes are there. ie. if only gfp is used,
    gfp.h, if slab is used, slab.h.

    * When the script inserts a new include, it looks at the include
    blocks and try to put the new include such that its order conforms
    to its surrounding. It's put in the include block which contains
    core kernel includes, in the same order that the rest are ordered -
    alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
    doesn't seem to be any matching order.

    * If the script can't find a place to put a new include (mostly
    because the file doesn't have fitting include block), it prints out
    an error message indicating which .h file needs to be added to the
    file.

    The conversion was done in the following steps.

    1. The initial automatic conversion of all .c files updated slightly
    over 4000 files, deleting around 700 includes and adding ~480 gfp.h
    and ~3000 slab.h inclusions. The script emitted errors for ~400
    files.

    2. Each error was manually checked. Some didn't need the inclusion,
    some needed manual addition while adding it to implementation .h or
    embedding .c file was more appropriate for others. This step added
    inclusions to around 150 files.

    3. The script was run again and the output was compared to the edits
    from #2 to make sure no file was left behind.

    4. Several build tests were done and a couple of problems were fixed.
    e.g. lib/decompress_*.c used malloc/free() wrappers around slab
    APIs requiring slab.h to be added manually.

    5. The script was run on all .h files but without automatically
    editing them as sprinkling gfp.h and slab.h inclusions around .h
    files could easily lead to inclusion dependency hell. Most gfp.h
    inclusion directives were ignored as stuff from gfp.h was usually
    wildly available and often used in preprocessor macros. Each
    slab.h inclusion directive was examined and added manually as
    necessary.

    6. percpu.h was updated not to include slab.h.

    7. Build test were done on the following configurations and failures
    were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my
    distributed build env didn't work with gcov compiles) and a few
    more options had to be turned off depending on archs to make things
    build (like ipr on powerpc/64 which failed due to missing writeq).

    * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
    * powerpc and powerpc64 SMP allmodconfig
    * sparc and sparc64 SMP allmodconfig
    * ia64 SMP allmodconfig
    * s390 SMP allmodconfig
    * alpha SMP allmodconfig
    * um on x86_64 SMP allmodconfig

    8. percpu.h modifications were reverted so that it could be applied as
    a separate patch and serve as bisection point.

    Given the fact that I had only a couple of failures from tests on step
    6, I'm fairly confident about the coverage of this conversion patch.
    If there is a breakage, it's likely to be something in one of the arch
    headers which should be easily discoverable easily on most builds of
    the specific arch.

    Signed-off-by: Tejun Heo <tj@kernel.org>
    Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org>
    Cc: Ingo Molnar <mingo@redhat.com>
    Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

    Tejun Heo
     

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
     

11 Dec, 2008

1 commit

  • 9c2462472   KSYM_SYMBOL_LEN fixes ... Browse Code »

    Miles Lane tailing /sys files hit a BUG which Pekka Enberg has tracked
    to my 966c8c12dc9e77f931e2281ba25d2f0244b06949 sprint_symbol(): use
    less stack exposing a bug in slub's list_locations() -
    kallsyms_lookup() writes a 0 to namebuf[KSYM_NAME_LEN-1], but that was
    beyond the end of page provided.

    The 100 slop which list_locations() allows at end of page looks roughly
    enough for all the other stuff it might print after the symbol before
    it checks again: break out KSYM_SYMBOL_LEN earlier than before.

    Latencytop and ftrace and are using KSYM_NAME_LEN buffers where they
    need KSYM_SYMBOL_LEN buffers, and vmallocinfo a 2*KSYM_NAME_LEN buffer
    where it wants a KSYM_SYMBOL_LEN buffer: fix those before anyone copies
    them.

    [akpm@linux-foundation.org: ftrace.h needs module.h]
    Signed-off-by: Hugh Dickins
    Cc: Christoph Lameter
    Cc Miles Lane
    Acked-by: Pekka Enberg
    Acked-by: Steven Rostedt
    Acked-by: Frederic Weisbecker
    Cc: Rusty Russell
    Signed-off-by: Andrew Morton
    Signed-off-by: Linus Torvalds

    Hugh Dickins
     

29 Apr, 2008

1 commit

20 Apr, 2008

1 commit

26 Jan, 2008

1 commit