I was looking for the trinity oops cause in the uncore driver.
(so far didn't found it)
However I found this tiny race: when a box is set up two threads on the
same CPU, they may be setting up the box in parallel (e.g. with kernel
preemption). This could lead to the reference count being increasing
too much. Always recheck there is no existing cpu reference inside the lock.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Link: http://lkml.kernel.org/r/1411424826-15629-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On systems with more than one socket perf stat --per-core would either
segfault or stop before outputting all cores.
The problem was that the output code referenced the id including the
socket number in the higher bits, which is far beyond any per cpu array.
Mask out the socket number before referencing cpus in abs_printout.
I also renamed the variable in nsec_printout to be clear what it is,
even though it doesn't reference cpus.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Stephane Eranian <eranian@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1411591846-32736-1-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The IvyBridge-EP uncore driver was missing three filter flags:
NC, ISOC, C6 which are useful in some cases. Support them in the same way
as the Haswell EP driver, by allowing to set them and exposing
them in the sysfs formats.
Also fix a typo in a define.
Relies on the Haswell EP driver to be applied earlier.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1409872109-31645-4-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Use the newly added Broadwell cache event list for Haswell too.
All Haswell and Broadwell events and offcore masks used in these lists
are identical.
However Haswell is very different from the Sandy Bridge
list that was used previously. That fixes a wide range of mis-counting
cache events.
The node events are now only for retired memory events, so prefetching
and speculative memory accesses are not included. They are PEBS
capable now, which makes it much easier to sample for them, plus it's
possible to create address maps with -d.
The prefetch events are gone now. They way the hardware counts
them is very misleading (some prefetches included, others not), so
it seemed best to leave them out.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1409683455-29168-5-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On Broadwell INST_RETIRED.ALL cannot be used with any period
that doesn't have the lowest 6 bits cleared. And the period
should not be smaller than 128.
Add a new callback to enforce this, and set it for Broadwell.
This is erratum BDM57 and BDM11.
How does this handle the case when an app requests a specific
period with some of the bottom bits set
The apps thinks it is sampling at X occurences per sample, when it is
in fact at X - 63 (worst case).
Short answer:
Any useful instruction sampling period needs to be 4-6 orders
of magnitude larger than 128, as an PMI every 128 instructions
would instantly overwhelm the system and be throttled.
So the +-64 error from this is really small compared to the
period, much smaller than normal system jitter.
Long answer:
<write up by Peter:>
IFF we guarantee perf_event_attr::sample_period >= 128.
Suppose we start out with sample_period=192; then we'll set period_left
to 192, we'll end up with left = 128 (we truncate the lower bits). We
get an interrupt, find that period_left = 64 (>0 so we return 0 and
don't get an overflow handler), up that to 128. Then we trigger again,
at n=256. Then we find period_left = -64 (<=0 so we return 1 and do get
an overflow). We increment with sample_period so we get left = 128. We
fire again, at n=384, period_left = 0 (<=0 so we return 1 and get an
overflow). And on and on.
So while the individual interrupts are 'wrong' we get then with
interval=256,128 in exactly the right ratio to average out at 192. And
this works for everything >=128.
So the num_samples*fixed_period thing is still entirely correct +- 127,
which is good enough I'd say, as you already have that error anyhow.
So no need to 'fix' the tools, al we need to do is refuse to create
INST_RETIRED:ALL events with sample_period < 128.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Maria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Cc: Mark Davies <junk@eslaf.co.uk>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1409683455-29168-4-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add Broadwell support for Broadwell Client to perf. This is very
similar to Haswell. It uses a new cache event table, because there
were various changes there.
The constraint list has one new event that needs to be handled over
Haswell.
The PEBS event list is the same, so we reuse Haswell's.
[fengguang.wu: make intel_bdw_event_constraints[] static]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: eranian@google.com
Link: http://lkml.kernel.org/r/1409683455-29168-3-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The new split Intel uncore driver code that recently went
into tip added a section mismatch, which the build process
complains about.
uncore_pmu_register() can be called from uncore_pci_probe,()
which is not __init and can be called from pci driver ->probe.
I'm not fully sure if it's actually possible to call the probe
function later, but it seems safer to mark uncore_pmu_register
not __init.
This also fixes the warning.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1409332858-29039-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
On larger systems intel_pstate currently spams the boot up
log with its "Intel pstate controlling ..." message for each CPU.
It's the only subsystem that prints a message for each
CPU.
Turn the message into a pr_debug.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Dirk Brandewie <dirk.j.brandewie@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Haswell supports reporting the data address for a range
of PEBS events, including:
UOPS_RETIRED.ALL
MEM_UOPS_RETIRED.STLB_MISS_LOADS
MEM_UOPS_RETIRED.STLB_MISS_STORES
MEM_UOPS_RETIRED.LOCK_LOADS
MEM_UOPS_RETIRED.SPLIT_LOADS
MEM_UOPS_RETIRED.SPLIT_STORES
MEM_UOPS_RETIRED.ALL_LOADS
MEM_UOPS_RETIRED.ALL_STORES
MEM_LOAD_UOPS_RETIRED.L1_HIT
MEM_LOAD_UOPS_RETIRED.L2_HIT
MEM_LOAD_UOPS_RETIRED.L3_HIT
MEM_LOAD_UOPS_RETIRED.L1_MISS
MEM_LOAD_UOPS_RETIRED.L2_MISS
MEM_LOAD_UOPS_RETIRED.L3_MISS
MEM_LOAD_UOPS_RETIRED.HIT_LFB
MEM_LOAD_UOPS_L3_HIT_RETIRED.XSNP_MISS
MEM_LOAD_UOPS_L3_HIT_RETIRED.XSNP_HIT
MEM_LOAD_UOPS_L3_HIT_RETIRED.XSNP_HITM
MEM_LOAD_UOPS_L3_HIT_RETIRED.XSNP_NONE
MEM_LOAD_UOPS_L3_MISS_RETIRED.LOCAL_DRAM
This facility was already enabled earlier with the original Haswell
perf changes.
However these addresses were always reports as stores by perf, which is wrong,
as they could be loads too. The hardware does not distinguish loads and stores
for these instructions, so there's no (cheap) way for the profiler
to find out.
Change the type to PERF_MEM_OP_NA instead.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Link: http://lkml.kernel.org/r/1407785233-32193-3-git-send-email-eranian@google.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The basic idea is that it does not make sense to list all PEBS
events individually. The list is very long, sometimes outdated
and the hardware doesn't need it. If an event does not support
PEBS it will just not count, there is no security issue.
We need to only list events that something special, like
supporting load or store addresses.
This vastly simplifies the PEBS event selection. It also
speeds up the scheduling because the scheduler doesn't
have to walk as many constraints.
Bugs fixed:
- We do not allow setting forbidden flags with PEBS anymore
(SDM 18.9.4), except for the special cycle event.
This is done using a new constraint macro that also
matches on the event flags.
- Correct DataLA and load/store/na flags reporting on Haswell
[Requires a followon patch]
- We did not allow all PEBS events on Haswell:
We were missing some valid subevents in d1-d2 (MEM_LOAD_UOPS_RETIRED.*,
MEM_LOAD_UOPS_RETIRED_L3_HIT_RETIRED.*)
This includes the changes proposed by Stephane earlier and obsoletes
his patchkit (except for some changes on pre Sandy Bridge/Silvermont
CPUs)
I only did Sandy Bridge and Silvermont and later so far, mostly because these
are the parts I could directly confirm the hardware behavior with hardware
architects. Also I do not believe the older CPUs have any
missing events in their PEBS list, so there's no pressing
need to change them.
I did not implement the flag proposed by Peter to allow
setting forbidden flags. If really needed this could
be implemented on to of this patch.
v2: Fix broken store events on SNB/IVB (Stephane Eranian)
v3: More fixes. Rename some arguments (Stephane Eranian)
v4: List most Haswell events individually again to report
memory operation type correctly.
Add new flags to describe load/store/na for datala.
Update description.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1407785233-32193-2-git-send-email-eranian@google.com
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Maria Dimakopoulou <maria.n.dimakopoulou@gmail.com>
Cc: Mark Davies <junk@eslaf.co.uk>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Yan, Zheng <zheng.z.yan@intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
HSW-EP has a larger offcore mask than the client Haswell CPUs.
It is the same mask as on Sandy/IvyBridge-EP. All of
Haswell was using the client mask, so some bits were missing.
On the client parts some bits were also missing compared
to Sandy/IvyBridge, in particular the bits to match on a L4
cache hit.
The Haswell core in both client and server incarnations
accepts the same bits (but some are nops), so we can use
the same mask.
So use the snbep extended mask, which is a superset of the
client and the server, for all of Haswell.
This allows specifying a number of extra offcore events, like
for example for HSW-EP.
% perf stat -e cpu/event=0xb7,umask=0x1,offcore_rsp=0x3fffc00100,name=offcore_response_pf_l3_rfo_l3_miss_any_response/ true
which were <not supported> before.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: eranian@google.com
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Link: http://lkml.kernel.org/r/1406840722-25416-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
When a hwpoison page is locked it could change state due to parallel
modifications. The original compound page can be torn down and then
this 4k page becomes part of a differently-size compound page is is a
standalone regular page.
Check after the lock if the page is still the same compound page.
We could go back, grab the new head page and try again but it should be
quite rare, so I thought this was safest. A retry loop would be more
difficult to test and may have more side effects.
The hwpoison code by design only tries to handle cases that are
reasonably common in workloads, as visible in page-flags.
I'm not really that concerned about handling this (likely rare case),
just not crashing on it.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I found that a lot of unresolvable variables when using gdb on the
kernel become resolvable when dwarf4 is enabled. So add a Kconfig flag
to enable it.
It definitely increases the debug information size, but on the other
hand this isn't so bad when debug fusion is used.
v2: Use cc-option
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
This is an alternative approach to lower the overhead of debug info
(as we discussed a few days ago)
gcc 4.7+ and newer binutils have a new "split debug info" debug info
model where the debug info is only written once into central ".dwo" files.
This avoids having to copy it around multiple times, from the object
files to the final executable. It lowers the disk space
requirements. In addition it defaults to compressed debug data.
More details here: http://gcc.gnu.org/wiki/DebugFission
This patch adds a new option to enable it. It has to be an option,
because it'll undoubtedly break everyone's debuginfo packaging scheme.
gdb/objdump/etc. all still work, if you have new enough versions.
I don't see big compile wins (maybe a second or two faster or so), but the
object dirs with debuginfo get significantly smaller. My standard kernel
config (slightly bigger than defconfig) shrinks from 2.9G disk space
to 1.1G objdir (with non reduced debuginfo). I presume if you are IO limited
the compile time difference will be larger.
Only problem I've seen so far is that it doesn't play well with older
versions of ccache (apparently fixed, see
https://bugzilla.samba.org/show_bug.cgi?id=10005)
v2: various fixes from Dirk Gouders. Improve commit message slightly.
v3: Fix clean rules and improve Kconfig slightly
v4: Fix merge error in last version (Sam Ravnborg)
Clarify description that it mainly helps disk size.
Cc: Dirk Gouders <dirk@gouders.net>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Out of lining these two common inlines saves about 30k text size,
due to their errata workarounds.
14131431 2008136 1507328 17646895 10d452f vmlinux-before-e1000e
14101415 2004040 1507328 17612783 10cbfef vmlinux-e1000e
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
perf stat did initialize the stats structure used to compute
stddev etc. incorrectly. It merely zeroes it. But one member
(min) needs to be set to a non zero value. This causes min
to be not computed at all. Call init_stats() correctly.
It doesn't matter for stat currently because it doesn't use
min, but it's still better to do it correctly.
The other users of statistics are already correct.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1395768699-16060-1-git-send-email-andi@firstfloor.org
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Work around a LTO gcc problem: when there is no reference to a variable
in a module it will be moved to the end of the program. This causes
reordering of initcalls which the kernel does not like.
Add a dummy reference function to avoid this. The function is
deleted by the linker.
This replaces a previous much slower workaround.
Thanks to Jan "Honza" Hubička for suggesting this technique.
Suggested-by: Jan Hubička <hubicka@ucw.cz>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1391846481-31491-4-git-send-email-ak@linux.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
In LTO symbols implicitely referenced by the compiler need
to be visible. Earlier these symbols were visible implicitely
from being exported, but we disabled implicit visibility fo
EXPORTs when modules are disabled to improve code size. So
now these symbols have to be marked visible explicitely.
Do this for __stack_chk_fail (with stack protector)
and memcmp.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1391845930-28580-10-git-send-email-ak@linux.intel.com
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
LTO in gcc 4.6/47. has trouble with global register variables. They were used
to read the stack pointer. Use a simple inline assembler statement with
a mov instead.
This also helps LLVM/clang, which does not support global register
variables.
[ hpa: Ideally this should become a builtin in both gcc and clang. ]
v2: More general asm constraint. Fix description (Jan Beulich)
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1382458079-24450-6-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The paravirt thunks use a hack of using a static reference to a static
function to reference that function from the top level statement.
This assumes that gcc always generates static function names in a specific
format, which is not necessarily true.
Simply make these functions global and asmlinkage or __visible. This way the
static __used variables are not needed and everything works.
Functions with arguments are __visible to keep the register calling
convention on 32bit.
Changed in paravirt and in all users (Xen and vsmp)
v2: Use __visible for functions with arguments
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Ido Yariv <ido@wizery.com>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1382458079-24450-5-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
The paravirt patching code assumes that it can reference a
local assembler label between two different top level assembler
statements. This does not work with LTO
where the assembler code may end up in different assembler files.
Replace it with extern / global /asm linkage labels.
This also removes one redundant copy of the macro.
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1382458079-24450-4-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Add a working sysctl to enable/disable automatic numa memory balancing
at runtime.
This allows us to track down performance problems with this feature and
is generally a good idea.
This was possible earlier through debugfs, but only with special
debugging options set. Also fix the boot message.
[akpm@linux-foundation.org: s/sched_numa_balancing/sysctl_numa_balancing/]
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
perf stat has a --delay option to delay measuring the workload.
This is useful to skip measuring the startup phase of the program, which
is often very different from the main workload.
The same is useful for perf record when sampling.
--no-delay was already taken, so add a --initial-delay
to perf record too.
-D was already taken for record, so there is only a long option.
v2: Don't disable group members (Namhyung Kim)
v3: port to latest perf/core
rename to --initial-delay to avoid conflict with --no-delay
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/1389476307-2124-1-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tell the compiler that the inline assembler statement
references lguest_entry.
This fixes compile problems with LTO where the variable
and the assembler code may end up in different files.
Cc: x86@kernel.org
Cc: rusty@rustcorp.com.au
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Disable static detection: the static currently drops a lot of useful
information including clones generated by gcc. Drop this. The statics
will appear now without static. prefix.
But remove the LTO .NUMBER postfixes that look ugly
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Michal Marek <mmarek@suse.cz>
Make the ksymtab symbols for EXPORT_SYMBOL visible.
This prevents the LTO compiler from adding a .NUMBER prefix,
which avoids various problems in later export processing.
Cc: rusty@rustcorp.com.au
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
The AMD_GART driver was made EXPERT/EMBEDDED a long time
ago to avoid unbootable 64bit systems with 32bit only devices.
This was before swiotlb was there, which does the job
of this fallback today. SWIOTLB is always on, so systems
should always boot.
The drawback is that every system has to compile that
driver in (it cannot be a module).
Also:
- Newer AMD CPUs (the APUs) don't seem to have AMD_GART support
at all anymore.
- Newer AMD platforms have a much better real IOMMU
- The AMD GART driver was never very good (lots of overhead,
e.g. in flushing due to some workarounds) and it's doubtful it's
really better than SWIOTLB.
- On older K8 systems it didn't even work with all chipsets.
- The 32bit device bounce buffer case should be rare/
non performance critical these days anyways.
- On non AMD systems it is not needed at all.
So drop the EXPERT dependency on AMD_GART and remove the
default y. The driver can be still compiled in, just
it's an explicit decision now, and people who don't want
it can unselect it.
I also clarified the description a bit.
This allows to save ~8K text on most modern x86-64 systems.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/1380922676-23007-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add a generic qualifier for transaction events, as a new sample
type that returns a flag word. This is particularly useful
for qualifying aborts: to distinguish aborts which happen
due to asynchronous events (like conflicts caused by another
CPU) versus instructions that lead to an abort.
The tuning strategies are very different for those cases,
so it's important to distinguish them easily and early.
Since it's inconvenient and inflexible to filter for this
in the kernel we report all the events out and allow
some post processing in user space.
The flags are based on the Intel TSX events, but should be fairly
generic and mostly applicable to other HTM architectures too. In addition
to various flag words there's also reserved space to report an
program supplied abort code. For TSX this is used to distinguish specific
classes of aborts, like a lock busy abort when doing lock elision.
Flags:
Elision and generic transactions (ELISION vs TRANSACTION)
(HLE vs RTM on TSX; IBM etc. would likely only use TRANSACTION)
Aborts caused by current thread vs aborts caused by others (SYNC vs ASYNC)
Retryable transaction (RETRY)
Conflicts with other threads (CONFLICT)
Transaction write capacity overflow (CAPACITY WRITE)
Transaction read capacity overflow (CAPACITY READ)
Transactions implicitely aborted can also return an abort code.
This can be used to signal specific events to the profiler. A common
case is abort on lock busy in a RTM eliding library (code 0xff)
To handle this case we include the TSX abort code
Common example aborts in TSX would be:
- Data conflict with another thread on memory read.
Flags: TRANSACTION|ASYNC|CONFLICT
- executing a WRMSR in a transaction. Flags: TRANSACTION|SYNC
- HLE transaction in user space is too large
Flags: ELISION|SYNC|CAPACITY-WRITE
The only flag that is somewhat TSX specific is ELISION.
This adds the perf core glue needed for reporting the new flag word out.
v2: Add MEM/MISC
v3: Move transaction to the end
v4: Separate capacity-read/write and remove misc
v5: Remove _SAMPLE. Move abort flags to 32bit. Rename
transaction to txn
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1379688044-14173-2-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Add support to perf stat to print the basic transactional execution statistics:
Total cycles, Cycles in Transaction, Cycles in aborted transsactions
using the in_tx and in_tx_checkpoint qualifiers.
Transaction Starts and Elision Starts, to compute the average transaction
length.
This is a reasonable overview over the success of the transactions.
Also support architectures that have a transaction aborted cycles
counter like POWER8. Since that is awkward to handle in the kernel
abstract handle both cases here.
Enable with a new --transaction / -T option.
This requires measuring these events in a group, since they depend on each
other.
This is implemented by using TM sysfs events exported by the kernel
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Arnaldo Carvalho de Melo <acme@infradead.org>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1377128846-977-5-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
tcp_established_options assumes opts->options is 0 before calling,
as it read modify writes it.
For the tcp_current_mss() case the opts structure is not zeroed,
so this can be done with uninitialized values.
This is ok, because ->options is not read in this path.
But it's still better to avoid the operation on the uninitialized
field. This shuts up a static code analyzer, and presumably
may help the optimizer.
Cc: netdev@vger.kernel.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
eee_get_cur assumes that the output data is already zeroed. It can
read-modify-write the advertised field:
if (ipcnfg & E1000_IPCNFG_EEE_100M_AN)
2594 edata->advertised |= ADVERTISED_100baseT_Full;
This is ok for the normal ethtool eee_get call, which always
zeroes the input data before.
But eee_set_cur also calls eee_get_cur and it did not zero the input
field. Later on it then compares agsinst the field, which can contain partial
stack garbage.
Zero the input field in eee_set_cur() too.
Cc: jeffrey.t.kirsher@intel.com
Cc: netdev@vger.kernel.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add TSX event aliases, and export them from the kernel to perf.
These are used by perf stat -T and to allow
more user friendly access to events. The events are designed to
be fairly generic and may also apply to other architectures
implementing HTM. They all cover common situations that
happens during tuning of transactional code.
For Haswell we have to separate the HLE and RTM events,
as they are separate in the PMU.
This adds the following events:
tx-start Count start transaction (used by perf stat -T)
tx-commit Count commit of transaction
tx-abort Count all aborts
tx-conflict Count aborts due to conflict with another CPU.
tx-capacity Count capacity aborts (transaction too large)
Then matching el-* events for HLE
cycles-t Transactional cycles (used by perf stat -T)
* also exists on POWER8
cycles-ct Transactional cycles commited (used by perf stat -T)
* according to Michael Ellerman POWER8 has a cycles-transactional-committed,
* perf stat -T handles both cases
Note for useful abort profiling often precise has to be set,
as Haswell can only report the point inside the transaction
with precise=2.
For some classes of aborts, like conflicts, this is not needed,
as it makes more sense to look at the complete critical section.
This gives a clean set of generalized events to examine transaction
success and aborts. Haswell has additional events for TSX, but those
are more specialized for very specific situations.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1378438661-24765-4-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Use the existing weight reporting facility to report the transaction
abort cost, that is the number of cycles wasted in aborts.
Haswell reports this in the PEBS record.
This was in fact the original user for weight.
This is a very useful sort key to concentrate on the most
costly aborts and a good metric for TSX tuning.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1378438661-24765-3-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
With checkpointed counters there can be a situation where the counter
is overflowing, aborts the transaction, is set back to a non overflowing
checkpoint, causes interupt. The interrupt doesn't see the overflow
because it has been checkpointed. This is then a spurious PMI, typically with
a ugly NMI message. It can also lead to excessive aborts.
Avoid this problem by:
- Using the full counter width for counting counters (earlier patch)
- Forbid sampling for checkpointed counters. It's not too useful anyways,
checkpointing is mainly for counting. The check is approximate
(to still handle KVM), but should catch the majority of cases.
- On a PMI always set back checkpointed counters to zero.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1378438661-24765-2-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
We cannot assume that the inline assembler code always ends up in the same
file as the original C file. So make any assembler labels that are called
with "extern" by C global
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Wim Van Sebroeck <wim@iguana.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The 64bit __copy_{from,to}_user_inatomic always called
copy_from_user_generic, but skipped the special optimizations for 1/2/4/8
byte accesses.
This especially hurts the futex call, which accesses the 4 byte futex
user value with a complicated fast string operation in a function call,
instead of a single movl.
Use __copy_{from,to}_user for _inatomic instead to get the same
optimizations. The only problem was the might_fault() in those functions.
So move that to new wrapper and call __copy_{f,t}_user_nocheck()
from *_inatomic directly.
32bit already did this correctly by duplicating the code.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1376687844-19857-2-git-send-email-andi@firstfloor.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Current code uses asmlinkage for functions without arguments.
This adds an implicit regparm(0) which creates a warning
when assigning the function to pointers.
Use __visible for the functions without arguments.
This avoids having to add regparm(0) to function pointers.
Since they have no arguments it does not make any difference.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1377115662-4865-1-git-send-email-andi@firstfloor.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
perf stat -a needs 10 open file descriptors per logical CPU
perf stat -a -dddd needs 20 open fds for each.
This implies that stat -a doesn't work on any system with the default
ulimit -n 1024 which has more than ~100 CPUs and stat -a -dddd doesn't
work on anything with more than 46 CPUs.
Longer term there needs to be probably some way to lower the file
descriptor requirements. This would need some changes in the kernel/user
interface.
But short term this patch just tries to increase the file descriptor
limit in perf itself, when it runs into a EMFILE.
It first sets it to the hard limit, and then tries to increase the hard
limit.
On Fedora systems the default seems to be soft limit 1024 and hard limit
4*1024. So even non root can support 409 or 186 CPUs respectively. root
can go far higher.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Link: http://lkml.kernel.org/r/1375670486-15480-1-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Tables used from assembler should be marked __visible to let
the compiler know.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
When measuring workloads the startup phase -- doing page faults, dynamic
linking, opening files -- is often very different from the rest of the
workload. Especially with smaller kernels and using counter
multiplexing this can give significant measurement errors.
Multiplexing assumes that the workload is mostly the same over longer
periods. But at startup there is typically some spike of activity which
is relatively short. If many groups are multiplexing the one group
seeing the spike, and which is then scaled up over the time to run all
groups, may see a significant error.
Also in general it's often not useful to measure the startup, because it
is so different from the rest.
One way around this is to use interval mode and discard the first
sample, but this can be awkward because interval mode doesn't support
intervals of less than 100ms, and also a useful interval is not
necessarily the same as a useful startup delay.
This patch adds a new --initial-delay / -D option to skip measuring for
the startup phase. The time can be specified in ms
Here's a simple example:
perf stat -e page-faults bash -c 'for i in $(seq 100000) ; do true ; done'
...
3,721 page-faults
...
If we just wait 20 ms the number of page faults is 1/3 less:
perf stat -D 20 -e page-faults bash -c 'for i in $(seq 100000) ; do true ; done'
...
2,823 page-faults
...
So we filtered out most of the startup noise from bash.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Reviewed-by: Jiri Olsa <jolsa@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1375490473-1503-4-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Andi Kleen