Stephane Eranian reported that doing a scheduler latency
measurements with perf on AMD doesn't work out as expected due
to the fact that the sched_clock() granularity is too coarse,
i.e. done in jiffies due to the sched_clock_stable not set,
which, if set, would mean that we get to use the TSC as sample
source which would give us much higher precision.
However, there's no reason not to set sched_clock_stable on AMD
because all families from F10h and upwards do have an invariant
TSC and have the CPUID flag to prove (CPUID_8000_0007_EDX[8]).
Make it so, #1.
Signed-off-by: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@amd64.org>
Cc: Venki Pallipadi <venki@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: Andreas Herrmann <andreas.herrmann3@amd.com>
Link: http://lkml.kernel.org/r/20120206132546.GA30854@quad
[ Should any non-standard system break the TSC, we should
mark them so explicitly, in their platform init handler, or
in a DMI quirk. ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Currently we can put the object files in a different directory by using
'O=' comand line argument.
However the generated documentation files don't honor this directive,
This patch fixes that. It's been tested for man target but the others
seems currently broken so no tests have been done on them so far.
Link: http://lkml.kernel.org/r/1328541443-18003-1-git-send-email-fbuihuu@gmail.com
Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
So that we can get the perf bench exec stack fixes and then apply the
remaining fix for the files added after what is in perf/urgent.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This patch fixes an issue where perf report shows nan% for certain
perf.data files. The below is from a report for a do_fork probe:
-nan% sshd [kernel.kallsyms] [k] do_fork
-nan% packagekitd [kernel.kallsyms] [k] do_fork
-nan% dbus-daemon [kernel.kallsyms] [k] do_fork
-nan% bash [kernel.kallsyms] [k] do_fork
A git bisect shows commit f3bda2c as the cause. However, looking back
through the git history, I saw commit 640c03c which seems to have
removed the required initialization for perf_sample->period. The problem
only started showing after commit f3bda2c. The below patch re-introduces
the initialization and it fixes the problem for me.
With the below patch, for the same perf.data:
73.08% bash [kernel.kallsyms] [k] do_fork
8.97% 11-dhclient [kernel.kallsyms] [k] do_fork
6.41% sshd [kernel.kallsyms] [k] do_fork
3.85% 20-chrony [kernel.kallsyms] [k] do_fork
2.56% sendmail [kernel.kallsyms] [k] do_fork
This patch applies over current linux-tip commit 9949284.
Problem introduced in:
$ git describe 640c03c
v2.6.37-rc3-83-g640c03c
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Robert Richter <robert.richter@amd.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: stable@kernel.org
Link: http://lkml.kernel.org/r/20120203170113.5190.25558.stgit@localhost6.localdomain6
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
In some perf ancient versions we used '[kernel.kallsyms._text]' as the
name for the kernel map.
This got changed with commit:
perf: 'perf kvm' tool for monitoring guest performance from host
commit a1645ce12a
Author: Zhang, Yanmin <yanmin_zhang@linux.intel.com>
and we started to use following name '[kernel.kallsyms]_text'.
This name change is important for the report code dealing with ancient
perf data. When processing the kernel map event, we need to recognize
the old naming (dont match the last ']') and initialize the kernel map
correctly.
The subsequent call to maps__set_kallsyms_ref_reloc_sym deals with the
superfluous ']' to get correct symbol name.
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1328461865-6127-1-git-send-email-jolsa@redhat.com
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
With the new throttling/unthrottling code introduced with
commit:
e050e3f0a7 ("perf: Fix broken interrupt rate throttling")
we occasionally hit two WARN_ON_ONCE() checks in:
- intel_pmu_pebs_enable()
- intel_pmu_lbr_enable()
- x86_pmu_start()
The assertions are no longer problematic. There is a valid
path where they can trigger but it is harmless.
The assertion can be triggered with:
$ perf record -e instructions:pp ....
Leading to paths:
intel_pmu_pebs_enable
intel_pmu_enable_event
x86_perf_event_set_period
x86_pmu_start
perf_adjust_freq_unthr_context
perf_event_task_tick
scheduler_tick
And:
intel_pmu_lbr_enable
intel_pmu_enable_event
x86_perf_event_set_period
x86_pmu_start
perf_adjust_freq_unthr_context.
perf_event_task_tick
scheduler_tick
cpuc->enabled is always on because when we get to
perf_adjust_freq_unthr_context() the PMU is not totally
disabled. Furthermore when we need to adjust a period,
we only stop the event we need to change and not the
entire PMU. Thus, when we re-enable, cpuc->enabled is
already set. Note that when we stop the event, both
pebs and lbr are stopped if necessary (and possible).
Signed-off-by: Stephane Eranian <eranian@google.com>
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/20120202110401.GA30911@quad
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
rbd: fix safety of rbd_put_client()
rbd: fix a memory leak in rbd_get_client()
ceph: create a new session lock to avoid lock inversion
ceph: fix length validation in parse_reply_info()
ceph: initialize client debugfs outside of monc->mutex
ceph: change "ceph.layout" xattr to be "ceph.file.layout"
The rbd_client structure uses a kref to arrange for cleaning up and
freeing an instance when its last reference is dropped. The cleanup
routine is rbd_client_release(), and one of the things it does is
delete the rbd_client from rbd_client_list. It acquires node_lock
to do so, but the way it is done is still not safe.
The problem is that when attempting to reuse an existing rbd_client,
the structure found might already be in the process of getting
destroyed and cleaned up.
Here's the scenario, with "CLIENT" representing an existing
rbd_client that's involved in the race:
Thread on CPU A | Thread on CPU B
--------------- | ---------------
rbd_put_client(CLIENT) | rbd_get_client()
kref_put() | (acquires node_lock)
kref->refcount becomes 0 | __rbd_client_find() returns CLIENT
calls rbd_client_release() | kref_get(&CLIENT->kref);
| (releases node_lock)
(acquires node_lock) |
deletes CLIENT from list | ...and starts using CLIENT...
(releases node_lock) |
and frees CLIENT | <-- but CLIENT gets freed here
Fix this by having rbd_put_client() acquire node_lock. The result
could still be improved, but at least it avoids this problem.
Signed-off-by: Alex Elder <elder@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>
This fixes the race in process_vm_core found by Oleg (see
http://article.gmane.org/gmane.linux.kernel/1235667/
for details).
This has been updated since I last sent it as the creation of the new
mm_access() function did almost exactly the same thing as parts of the
previous version of this patch did.
In order to use mm_access() even when /proc isn't enabled, we move it to
kernel/fork.c where other related process mm access functions already
are.
Signed-off-by: Chris Yeoh <yeohc@au1.ibm.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If an existing rbd client is found to be suitable for use in
rbd_get_client(), the rbd_options structure is not being
freed as it should. Fix that.
Signed-off-by: Alex Elder <elder@dreamhost.com>
Signed-off-by: Sage Weil <sage@newdream.net>
Lockdep was reporting a possible circular lock dependency in
dentry_lease_is_valid(). That function needs to sample the
session's s_cap_gen and and s_cap_ttl fields coherently, but needs
to do so while holding a dentry lock. The s_cap_lock field was
being used to protect the two fields, but that can't be taken while
holding a lock on a dentry within the session.
In most cases, the s_cap_gen and s_cap_ttl fields only get operated
on separately. But in three cases they need to be updated together.
Implement a new lock to protect the spots updating both fields
atomically is required.
Signed-off-by: Alex Elder <elder@dreamhost.com>
Reviewed-by: Sage Weil <sage@newdream.net>
"len" is read from network and thus needs validation. Otherwise, given
a bogus "len" value, p+len could be an out-of-bounds pointer, which is
used in further parsing.
Signed-off-by: Xi Wang <xi.wang@gmail.com>
Signed-off-by: Sage Weil <sage@newdream.net>
Initializing debufs under monc->mutex introduces a lock dependency for
sb->s_type->i_mutex_key, which (combined with several other dependencies)
leads to an annoying lockdep warning. There's no particular reason to do
the debugfs setup under this lock, so move it out.
It used to be the case that our first monmap could come from the OSD; that
is no longer the case with recent servers, so we will reliably set up the
client entry during the initial authentication.
We don't have to worry about racing with debugfs teardown by
ceph_debugfs_client_cleanup() because ceph_destroy_client() calls
ceph_msgr_flush() first, which will wait for the message dispatch work
to complete (and the debugfs init to complete).
Fixes: #1940
Signed-off-by: Sage Weil <sage@newdream.net>
The virtual extended attribute named "ceph.layout" is meaningful
only for regular files. Change its name to be "ceph.file.layout" to
more directly reflect that in the ceph xattr namespace. Preserve
the old "ceph.layout" name for the time being (until we decide it's
safe to get rid of it entirely).
Add a missing initializer for "readonly" in the terminating entry.
Signed-off-by: Alex Elder <elder@dreamhost.com>
Reviewed-by: Sage Weil <sage@newdream.net>
Fernando Luis Vázquez Cao
Borislav Petkov
Ingo Molnar
Namhyung Kim
Franck Bui-Huu
Jiri Olsa
Arnaldo Carvalho de Melo
Naveen N. Rao
Stephane Eranian
Linus Torvalds
Josh Triplett
Alex Elder
Christopher Yeoh
Xi Wang
Sage Weil
Robert Richter