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2013-07-09perf record: Remove -f/--force optionJiri Olsa1-4/+0
It no longer have any affect on the processing and is marked as obsolete anyway. Signed-off-by: Jiri Olsa <jolsa@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-tvwyspiqr4getzfib2lw06ty@git.kernel.org Link: http://lkml.kernel.org/r/1372307120-737-1-git-send-email-namhyung@kernel.org [ combined patch removing the -f usage in various sub-commands, such as 'perf sched', etc, by Namhyung Kim ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-07-09perf record: Remove -A/--append optionJiri Olsa1-3/+1
It's no longer working and needed. Quite straightforward discussion/vote was in here: http://marc.info/?t=137028288300004&r=1&w=2 Signed-off-by: Jiri Olsa <jolsa@redhat.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com> Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Link: http://lkml.kernel.org/n/tip-8fgdva12hl8w3xzzpsvvg7nx@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2013-04-01perf tools: Add support for weight v7 (modified)Andi Kleen1-0/+6
perf record has a new option -W that enables weightened sampling. Add sorting support in top/report for the average weight per sample and the total weight sum. This allows to both compare relative cost per event and the total cost over the measurement period. Add the necessary glue to perf report, record and the library. v2: Merge with new hist refactoring. v3: Fix manpage. Remove value check. Rename global_weight to weight and weight to local_weight. v4: Readd sort keys to manpage v5: Move weight to end v6: Move weight to template v7: Rename weight key. Original patch from Andi modified by Stephane Eranian <eranian@google.com> to include ONLY the weight supporting code and apply to pristine 3.8.0-rc4. Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung.kim@lge.com> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1359040242-8269-6-git-send-email-eranian@google.com [ committer note: changed to cope with fc5871ed and the hists_link perf test entry ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-12-03treewide: Fix typos in various driversMasanari Iida1-1/+1
Fix typos in printk within various drivers. Signed-off-by: Masanari Iida <standby24x7@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
2012-05-22perf record: Fix documentation for branch stack samplingAnshuman Khandual1-1/+1
Signed-off-by: Anshuman Khandual <khandual@linux.vnet.ibm.com> Acked-by: Stephane Eranian <eranian@google.com> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/r/4FB60C7A.2080508@linux.vnet.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-03-09perf record: Provide default branch stack sampling mode optionStephane Eranian1-9/+14
This patch chanegs the logic of the -b, --branch-stack options of perf record. Based on users' request, the patch provides a default filter mode with the -b (or --branch-any) option. With the option, any type of taken branches is sampled. With -j (or --branch-filter), the user can specify any valid combination of branch types and privilege levels if supported by the underlying hardware. The -b (--branch any) is a shortcut for: --branch-filter any. $ perf record -b foo or: $ perf record --branch-filter any foo For more specific filtering: $ perf record --branch-filter ind_call,u foo Signed-off-by: Stephane Eranian <eranian@google.com> Cc: peterz@infradead.org Cc: acme@redhat.com Cc: asharma@fb.com Cc: ravitillo@lbl.gov Cc: vweaver1@eecs.utk.edu Cc: khandual@linux.vnet.ibm.com Cc: dsahern@gmail.com Link: http://lkml.kernel.org/r/1331246868-19905-2-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-03-09perf record: Add support for sampling taken branchRoberto Agostino Vitillo1-0/+25
This patch adds a new option to enable taken branch stack sampling, i.e., leverage the PERF_SAMPLE_BRANCH_STACK feature of perf_events. There is a new option to active this mode: -b. It is possible to pass a set of filters to select the type of branches to sample. The following filters are available: - any : any type of branches - any_call : any function call or system call - any_ret : any function return or system call return - any_ind : any indirect branch - u: only when the branch target is at the user level - k: only when the branch target is in the kernel - hv: only when the branch target is in the hypervisor Filters can be combined by passing a comma separated list to the option: $ perf record -b any_call,u -e cycles:u branchy Signed-off-by: Roberto Agostino Vitillo <ravitillo@lbl.gov> Signed-off-by: Stephane Eranian <eranian@google.com> Cc: peterz@infradead.org Cc: acme@redhat.com Cc: robert.richter@amd.com Cc: ming.m.lin@intel.com Cc: andi@firstfloor.org Cc: asharma@fb.com Cc: vweaver1@eecs.utk.edu Cc: khandual@linux.vnet.ibm.com Cc: dsahern@gmail.com Link: http://lkml.kernel.org/r/1328826068-11713-13-git-send-email-eranian@google.com Signed-off-by: Ingo Molnar <mingo@elte.hu>
2012-02-14perf tools: Allow multiple threads or processes in record, stat, topDavid Ahern1-2/+2
Allow a user to collect events for multiple threads or processes using a comma separated list. e.g., collect data on a VM and its vhost thread: perf top -p 21483,21485 perf stat -p 21483,21485 -ddd perf record -p 21483,21485 or monitoring vcpu threads perf top -t 21488,21489 perf stat -t 21488,21489 -ddd perf record -t 21488,21489 Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/1328718772-16688-1-git-send-email-dsahern@gmail.com Signed-off-by: David Ahern <dsahern@gmail.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2012-01-25perf tools: Introduce per user viewArnaldo Carvalho de Melo1-0/+4
The new --uid command line option will show only the tasks for a given user, using the proc interface to figure out the existing tasks. Kernel work is needed to close races at startup, but this should already be useful in many use cases. Cc: David Ahern <dsahern@gmail.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lkml.kernel.org/n/tip-bdnspm000gw2l984a2t53o8z@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2011-12-23perf: builtin-record: Document and check that mmap_pages must be a power of two.Nelson Elhage1-1/+1
Now that we automatically point users at it, let's provide them some guidance so that they hopefully don't just get mysterious EINVAL's from the kernel. 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/1324301972-22740-4-git-send-email-nelhage@nelhage.com Signed-off-by: Nelson Elhage <nelhage@nelhage.com> [ committer note: Made it work after 50a682c ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2011-02-16perf tool: Add cgroup supportStephane Eranian1-0/+11
This patch adds the ability to filter monitoring based on container groups (cgroups) for both perf stat and perf record. It is possible to monitor multiple cgroup in parallel. There is one cgroup per event. The cgroups to monitor are passed via a new -G option followed by a comma separated list of cgroup names. The cgroup filesystem has to be mounted. Given a cgroup name, the perf tool finds the corresponding directory in the cgroup filesystem and opens it. It then passes that file descriptor to the kernel. Example: $ perf stat -B -a -e cycles:u,cycles:u,cycles:u -G test1,,test2 -- sleep 1 Performance counter stats for 'sleep 1': 2,368,667,414 cycles test1 2,369,661,459 cycles <not counted> cycles test2 1.001856890 seconds time elapsed Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <4d590290.825bdf0a.7d0a.4890@mx.google.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2011-01-13perf record: Add "nodelay" mode, disabled by defaultKirill Smelkov1-0/+3
Sometimes there is a need to use perf in "live-log" mode. The problem is, for seldom events, actual info output is largely delayed because perf-record reads sample data in whole pages. So for such scenarious, add flag for perf-record to go in "nodelay" mode. To track e.g. what's going on in icmp_rcv while ping is running Use it with something like this: (1) $ perf probe -L icmp_rcv | grep -U8 '^ *43\>' goto error; } 38 if (!pskb_pull(skb, sizeof(*icmph))) goto error; icmph = icmp_hdr(skb); 43 ICMPMSGIN_INC_STATS_BH(net, icmph->type); /* * 18 is the highest 'known' ICMP type. Anything else is a mystery * * RFC 1122: 3.2.2 Unknown ICMP messages types MUST be silently * discarded. */ 50 if (icmph->type > NR_ICMP_TYPES) goto error; $ perf probe icmp_rcv:43 'type=icmph->type' (2) $ cat trace-icmp.py [...] def trace_begin(): print "in trace_begin" def trace_end(): print "in trace_end" def probe__icmp_rcv(event_name, context, common_cpu, common_secs, common_nsecs, common_pid, common_comm, __probe_ip, type): print_header(event_name, common_cpu, common_secs, common_nsecs, common_pid, common_comm) print "__probe_ip=%u, type=%u\n" % \ (__probe_ip, type), [...] (3) $ perf record -a -D -e probe:icmp_rcv -o - | \ perf script -i - -s trace-icmp.py Thanks to Peter Zijlstra for pointing how to do it. Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu>, Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <20110112140613.GA11698@tugrik.mns.mnsspb.ru> Signed-off-by: Kirill Smelkov <kirr@mns.spb.ru> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-12-05perf tools: Ask for ID PERF_SAMPLE_ info on all PERF_RECORD_ eventsArnaldo Carvalho de Melo1-0/+5
So that we can use -T == --timestamp, asking for PERF_SAMPLE_TIME: $ perf record -aT $ perf report -D | grep PERF_RECORD_ <SNIP> 3 5951915425 0x47530 [0x58]: PERF_RECORD_SAMPLE(IP, 1): 16811/16811: 0xffffffff8138c1a2 period: 215979 cpu:3 3 5952026879 0x47588 [0x90]: PERF_RECORD_SAMPLE(IP, 1): 16811/16811: 0xffffffff810cb480 period: 215979 cpu:3 3 5952059959 0x47618 [0x38]: PERF_RECORD_FORK(6853:6853):(16811:16811) 3 5952138878 0x47650 [0x78]: PERF_RECORD_SAMPLE(IP, 1): 16811/16811: 0xffffffff811bac35 period: 431478 cpu:3 3 5952375068 0x476c8 [0x30]: PERF_RECORD_COMM: find:6853 3 5952395923 0x476f8 [0x50]: PERF_RECORD_MMAP 6853/6853: [0x400000(0x25000) @ 0]: /usr/bin/find 3 5952413756 0x47748 [0xa0]: PERF_RECORD_SAMPLE(IP, 1): 6853/6853: 0xffffffff810d080f period: 859332 cpu:3 3 5952419837 0x477e8 [0x58]: PERF_RECORD_MMAP 6853/6853: [0x3f44600000(0x21d000) @ 0]: /lib64/ld-2.5.so 3 5952437929 0x47840 [0x48]: PERF_RECORD_MMAP 6853/6853: [0x7fff7e1c9000(0x1000) @ 0x7fff7e1c9000]: [vdso] 3 5952570127 0x47888 [0x58]: PERF_RECORD_MMAP 6853/6853: [0x3f46200000(0x218000) @ 0]: /lib64/libselinux.so.1 3 5952623637 0x478e0 [0x58]: PERF_RECORD_MMAP 6853/6853: [0x3f44a00000(0x356000) @ 0]: /lib64/libc-2.5.so 3 5952675720 0x47938 [0x58]: PERF_RECORD_MMAP 6853/6853: [0x3f44e00000(0x204000) @ 0]: /lib64/libdl-2.5.so 3 5952710080 0x47990 [0x58]: PERF_RECORD_MMAP 6853/6853: [0x3f45a00000(0x246000) @ 0]: /lib64/libsepol.so.1 3 5952847802 0x479e8 [0x58]: PERF_RECORD_SAMPLE(IP, 1): 6853/6853: 0xffffffff813897f0 period: 1142536 cpu:3 <SNIP> First column is the cpu and the second the timestamp. That way we can investigate problems in the event stream. If the new perf binary is run on an older kernel, it will disable this feature automatically. Tested-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Ian Munsie <imunsie@au1.ibm.com> Acked-by: Thomas Gleixner <tglx@linutronix.de> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Ian Munsie <imunsie@au1.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Stephane Eranian <eranian@google.com> LKML-Reference: <1291318772-30880-5-git-send-email-acme@infradead.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-12-01perf record: Document missing optionsShawn Bohrer1-4/+13
Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1291168642-11402-9-git-send-email-shawn.bohrer@gmail.com> Signed-off-by: Shawn Bohrer <shawn.bohrer@gmail.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-10-26perf scripting: Shut up 'perf record' final statusArnaldo Carvalho de Melo1-0/+4
We want just the script output, not internal details about the record phase. Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <new-submission> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-06-17perf record: Add option to avoid updating buildid cacheStephane Eranian1-0/+6
There are situations where there is enough information in the perf.data to process the samples. Updating the buildid cache may add unecessary overhead in terms of disk space and time (copying large elf images). A persistent option to do this already exists via the perfconfig file, simply do: [buildid] dir = /dev/null This patch provides a way to suppress builid cache updates on a per-run basis. It addds a new option, -N, to perf record. Buildids are still generated in the perf.data file. Cc: David S. Miller <davem@davemloft.net> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <4c19ef89.93ecd80a.40dc.fffff8e9@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-06-05perf tools: Add the ability to specify list of cpus to monitorStephane Eranian1-0/+7
This patch adds a -C option to stat, record, top to designate a list of CPUs to monitor. CPUs can be specified as a comma-separated list or ranges, no space allowed. Examples: $ perf record -a -C0-1,4-7 sleep 1 $ perf top -C0-4 $ perf stat -a -C1,2,3,4 sleep 1 With perf record in per-thread mode with inherit mode on, samples are collected only when the thread runs on the designated CPUs. The -C option does not turn on system-wide mode automatically. Cc: David S. Miller <davem@davemloft.net> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Zanussi <tzanussi@gmail.com> LKML-Reference: <4bff9496.d345d80a.41fe.7b00@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-13perf tools: change event inheritance logic in stat and recordStephane Eranian1-2/+2
By default, event inheritance across fork and pthread_create was on but the -i option of stat and record, which enabled inheritance, led to believe it was off by default. This patch fixes this logic by inverting the meaning of the -i option. By default inheritance is on whether you attach to a process (-p), a thread (-t) or start a process. If you pass -i, then you turn off inheritance. Turning off inheritance if you don't need it, helps limit perf resource usage as well. The patch also fixes perf stat -t xxxx and perf record -t xxxx which did not start the counters. Acked-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: David S. Miller <davem@davemloft.net> Cc: Frédéric Weisbecker <fweisbec@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <4bea9d2f.d60ce30a.0b5b.08e1@mx.google.com> Signed-off-by: Stephane Eranian <eranian@google.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-04-15perf: Always record tracepoints raw samples from perf recordFrederic Weisbecker1-1/+1
Trace events are mostly used for tracing rather than simple counting. Don't bother anymore with adding -R when using them, just record raw samples of trace events every time. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de>
2010-04-15perf: Make -f the default for perf recordFrederic Weisbecker1-1/+1
Force the overwriting mode by default if append mode is not explicit. Adding -f every time one uses perf on a daily basis quickly becomes a burden. Keep the -f among the options though to avoid breaking some random users scripts. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Paul Mackerras <paulus@samba.org> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de>
2009-11-23perf tools: Add support for breakpoint events in perf toolsFrederic Weisbecker1-4/+12
Add the breakpoint events support with this new sysnopsis: mem:addr[:access] Where addr is a raw addr value in the kernel and access can be either [r][w][x] Example to profile tasklist_lock: $ grep tasklist_lock /proc/kallsyms ffffffff8189c000 D tasklist_lock $ perf record -e mem:0xffffffff8189c000:rw -a -f -c 1 $ perf report # Samples: 62 # # Overhead Command Shared Object Symbol # ........ ............... ............. ...... # 29.03% swapper [kernel] [k] _raw_read_trylock 29.03% swapper [kernel] [k] _raw_read_unlock 19.35% init [kernel] [k] _raw_read_trylock 19.35% init [kernel] [k] _raw_read_unlock 1.61% events/0 [kernel] [k] _raw_read_trylock 1.61% events/0 [kernel] [k] _raw_read_unlock Coming soon: - Support for symbols in the event definition. - Default period to 1 for breakpoint events because these are not high frequency events. The same thing is needed for trace events. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Prasad <prasad@linux.vnet.ibm.com> LKML-Reference: <1258987355-8751-4-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Prasad <prasad@linux.vnet.ibm.com>
2009-08-31perf tools: Add missing parameters documentationFrederic Weisbecker1-0/+4
Add missing documentation for the following parameters: - perf record -R - perf report -g Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <1251682323-10395-1-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-08-05perf report: Add missing command line options to man pageArnaldo Carvalho de Melo1-3/+57
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> LKML-Reference: <20090805130453.GC10688@ghostprotocols.net> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-06-06perf_counter tools: Move from Documentation/perf_counter/ to tools/perf/Ingo Molnar1-0/+42
Several people have suggested that 'perf' has become a full-fledged tool that should be moved out of Documentation/. Move it to the (new) tools/ directory. Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> LKML-Reference: <new-submission> Signed-off-by: Ingo Molnar <mingo@elte.hu>