perf-kmem(1)
============

NAME
----
perf-kmem - Tool to trace/measure kernel memory properties

SYNOPSIS
--------
[verse]
'perf kmem' {record|stat} [<options>]

DESCRIPTION
-----------
There are two variants of perf kmem:

  'perf kmem record <command>' to record the kmem events
  of an arbitrary workload.

  'perf kmem stat' to report kernel memory statistics.

OPTIONS
-------
-i <file>::
--input=<file>::
	Select the input file (default: perf.data unless stdin is a fifo)

-v::
--verbose::
        Be more verbose. (show symbol address, etc)

--caller::
	Show per-callsite statistics

--alloc::
	Show per-allocation statistics

-s <key[,key2...]>::
--sort=<key[,key2...]>::
	Sort the output (default: 'frag,hit,bytes' for slab and 'bytes,hit'
	for page).  Available sort keys are 'ptr, callsite, bytes, hit,
	pingpong, frag' for slab and 'page, callsite, bytes, hit, order,
	migtype, gfp' for page.  This option should be preceded by one of the
	mode selection options - i.e. --slab, --page, --alloc and/or --caller.

-l <num>::
--line=<num>::
	Print n lines only

--raw-ip::
	Print raw ip instead of symbol

--slab::
	Analyze SLAB allocator events.

--page::
	Analyze page allocator events

--live::
	Show live page stat.  The perf kmem shows total allocation stat by
	default, but this option shows live (currently allocated) pages
	instead.  (This option works with --page option only)

--time::
	Only analyze samples within given time window: <start>,<stop>. Times
	have the format seconds.microseconds. If start is not given (i.e., time
	string is ',x.y') then analysis starts at the beginning of the file. If
	stop time is not given (i.e, time string is 'x.y,') then analysis goes
	to end of file.

SEE ALSO
--------
linkperf:perf-record[1]
/arm_arch_timer.h'>log</a><a href='/cgit.cgi/linux/net-next.git/tree/include/clocksource/arm_arch_timer.h?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>tree</a><a class='active' href='/cgit.cgi/linux/net-next.git/commit/include/clocksource/arm_arch_timer.h?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>commit</a><a href='/cgit.cgi/linux/net-next.git/diff/include/clocksource/arm_arch_timer.h?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>diff</a></td><td class='form'><form class='right' method='get' action='/cgit.cgi/linux/net-next.git/log/include/clocksource/arm_arch_timer.h'>
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/commit/?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>root</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>include</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include/clocksource?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>clocksource</a>/<a href='/cgit.cgi/linux/net-next.git/commit/include/clocksource/arm_arch_timer.h?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>arm_arch_timer.h</a></div><div class='content'><div class='cgit-panel'><b>diff options</b><form method='get'><input type='hidden' name='id' value='6e978b22efa1db9f6e71b24440b5f1d93e968ee3'/><table><tr><td colspan='2'/></tr><tr><td class='label'>context:</td><td class='ctrl'><select name='context' onchange='this.form.submit();'><option value='1'>1</option><option value='2'>2</option><option value='3' selected='selected'>3</option><option value='4'>4</option><option value='5'>5</option><option value='6'>6</option><option value='7'>7</option><option value='8'>8</option><option value='9'>9</option><option value='10'>10</option><option value='15'>15</option><option value='20'>20</option><option value='25'>25</option><option value='30'>30</option><option value='35'>35</option><option value='40'>40</option></select></td></tr><tr><td class='label'>space:</td><td class='ctrl'><select name='ignorews' onchange='this.form.submit();'><option value='0' selected='selected'>include</option><option value='1'>ignore</option></select></td></tr><tr><td class='label'>mode:</td><td class='ctrl'><select name='dt' onchange='this.form.submit();'><option value='0' selected='selected'>unified</option><option value='1'>ssdiff</option><option value='2'>stat only</option></select></td></tr><tr><td/><td class='ctrl'><noscript><input type='submit' value='reload'/></noscript></td></tr></table></form></div><table summary='commit info' class='commit-info'>
<tr><th>author</th><td>Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;</td><td class='right'>2017-02-03 14:18:39 -0800</td></tr>
<tr><th>committer</th><td>Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;</td><td class='right'>2017-02-04 00:11:08 +0100</td></tr>
<tr><th>commit</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/clocksource/arm_arch_timer.h?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>6e978b22efa1db9f6e71b24440b5f1d93e968ee3</a> (<a href='/cgit.cgi/linux/net-next.git/patch/include/clocksource/arm_arch_timer.h?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>patch</a>)</td></tr>
<tr><th>tree</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/tree/?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>c666f7a26b860674848949e39a610222b0723f89</a> /<a href='/cgit.cgi/linux/net-next.git/tree/include/clocksource/arm_arch_timer.h?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>include/clocksource/arm_arch_timer.h</a></td></tr>
<tr><th>parent</th><td colspan='2' class='oid'><a href='/cgit.cgi/linux/net-next.git/commit/include/clocksource/arm_arch_timer.h?id=3c223c19aea85d3dda1416c187915f4a30b04b1f'>3c223c19aea85d3dda1416c187915f4a30b04b1f</a> (<a href='/cgit.cgi/linux/net-next.git/diff/include/clocksource/arm_arch_timer.h?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3&amp;id2=3c223c19aea85d3dda1416c187915f4a30b04b1f'>diff</a>)</td></tr></table>
<div class='commit-subject'>cpufreq: intel_pstate: Disable energy efficiency optimization</div><div class='commit-msg'>Some Kabylake desktop processors may not reach max turbo when running in
HWP mode, even if running under sustained 100% utilization.

This occurs when the HWP.EPP (Energy Performance Preference) is set to
"balance_power" (0x80) -- the default on most systems.

It occurs because the platform BIOS may erroneously enable an
energy-efficiency setting -- MSR_IA32_POWER_CTL BIT-EE, which is not
recommended to be enabled on this SKU.

On the failing systems, this BIOS issue was not discovered when the
desktop motherboard was tested with Windows, because the BIOS also
neglects to provide the ACPI/CPPC table, that Windows requires to enable
HWP, and so Windows runs in legacy P-state mode, where this setting has
no effect.

Linux' intel_pstate driver does not require ACPI/CPPC to enable HWP, and
so it runs in HWP mode, exposing this incorrect BIOS configuration.

There are several ways to address this problem.

First, Linux can also run in legacy P-state mode on this system.
As intel_pstate is how Linux enables HWP, booting with
"intel_pstate=disable"
will run in acpi-cpufreq/ondemand legacy p-state mode.

Or second, the "performance" governor can be used with intel_pstate,
which will modify HWP.EPP to 0.

Or third, starting in 4.10, the
/sys/devices/system/cpu/cpufreq/policy*/energy_performance_preference
attribute in can be updated from "balance_power" to "performance".

Or fourth, apply this patch, which fixes the erroneous setting of
MSR_IA32_POWER_CTL BIT_EE on this model, allowing the default
configuration to function as designed.

Signed-off-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Reviewed-by: Len Brown &lt;len.brown@intel.com&gt;
Cc: 4.6+ &lt;stable@vger.kernel.org&gt; # 4.6+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
</div><div class='diffstat-header'><a href='/cgit.cgi/linux/net-next.git/diff/?id=6e978b22efa1db9f6e71b24440b5f1d93e968ee3'>Diffstat</a> (limited to 'include/clocksource/arm_arch_timer.h')</div><table summary='diffstat' class='diffstat'>