BMC/Intel-BMC/linux.git/tools/perf/util/intel-pt.c, branch dev-4.6

perf intel-pt: Fix segfault tracing transactions

2016-04-18T14:00:56+00:00

Tracing a workload that uses transactions gave a seg fault as follows: perf record -e intel_pt// workload perf report Program received signal SIGSEGV, Segmentation fault. 0x000000000054b58c in intel_pt_reset_last_branch_rb (ptq=0x1a36110) at util/intel-pt.c:929 929 ptq->last_branch_rb->nr = 0; (gdb) p ptq->last_branch_rb $1 = (struct branch_stack *) 0x0 (gdb) up 1148 intel_pt_reset_last_branch_rb(ptq); (gdb) l 1143 if (ret) 1144 pr_err("Intel Processor Trace: failed to deliver transaction event 1145 ret); 1146 1147 if (pt->synth_opts.callchain) 1148 intel_pt_reset_last_branch_rb(ptq); 1149 1150 return ret; 1151 } 1152 (gdb) p pt->synth_opts.callchain $2 = true (gdb) (gdb) bt #0 0x000000000054b58c in intel_pt_reset_last_branch_rb (ptq=0x1a36110) #1 0x000000000054c1e0 in intel_pt_synth_transaction_sample (ptq=0x1a36110) #2 0x000000000054c5b2 in intel_pt_sample (ptq=0x1a36110) Caused by checking the 'callchain' flag when it should have been the 'last_branch' flag. Fix that. Reported-by: Andi Kleen Signed-off-by: Adrian Hunter Cc: Jiri Olsa Cc: stable@vger.kernel.org # v4.4+ Fixes: f14445ee72c5 ("perf intel-pt: Support generating branch stack") Link: http://lkml.kernel.org/r/1460977068-11566-1-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Add missing initialization of perf_sample.cpumode in synthesized samples

2016-03-29T23:03:56+00:00

In 473398a21d28 ("perf tools: Add cpumode to struct perf_sample"), I missed some places where perf_sample fields are directly initialized in addition to what is done in perf_evsel__parse_sample(), namely when synthesizing PERF_RECORD_{MMAP*,COMM,FORK,EXIT} for pre-existing threads and also in intel_pt and intel_bts when synthesizing events from processor trace, the jitdump code also was affected, fix it. The problem was noticed with running: # perf record -e intel_pt//u true # perf script Where the samples wouldn't get resolved because perf_sample.cpumode would be left as zero, i.e. PERF_RECORD_MISC_CPUMODE_UNKNOWN, not resolving as kernel, hypervisor or user cpu modes. Cc: Alexander Shishkin Cc: Andi Kleen Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Fixes: 473398a21d28 ("perf tools: Add cpumode to struct perf_sample") Link: http://lkml.kernel.org/n/tip-n5sdauxgk24d5nun8kuuu2mh@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Fix thread lifetime related segfaut in intel_pt

2016-02-02T15:51:11+00:00

intel_pt_process_auxtrace_info() creates a pt->unknown_thread thread that eventually needs to be freed by the last thread__put() on it, when its refcount hits zero, which may happen in intel_pt_process_auxtrace_info() error handling path and triggers the following segfault, which would happen as well at intel_pt_free, when tools using this intel_pt codebase frees up resources: # perf record -I -e intel_pt/tsc=1,noretcomp=1/u /bin/ls 0 a anaconda-ks.cfg bin perf.data perf.data.old perf-f23-bringup.todo [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.217 MB perf.data ] # # perf script -F event,comm,pid,tid,time,addr,ip,sym,dso,iregs Samples for 'instructions:u' event do not have IREGS attribute set. Cannot print 'iregs' field. intel_pt_synth_events: failed to synthesize 'instructions' event type Segmentation fault (core dumped) # The problem is: there's a union in 'struct thread' combines a list_head and a rb_node. The standard life cycle of a thread is: init rb_node in the constructor, insert it into machine->threads rbtree using rb_node, move it to machine->dead_threads using list_head, clean in the last thread__put: list_del_init(&thread->node). In the above command, it clean a thread before adding it into list, causes the above segfault. Since pt->unknown_thread will never live in an rbtree, initialize its list node so that when list_del_init() is done on it we don't segfault. After this patch: # perf script -F event,comm,pid,tid,time,addr,ip,sym,dso,iregs Samples for 'instructions:u' event do not have IREGS attribute set. Cannot print 'iregs' field. intel_pt_synth_events: failed to synthesize 'instructions' event type 0x248 [0x88]: failed to process type: 70 # Reported-by: Tong Zhang Reported-by: Wang Nan Signed-off-by: Adrian Hunter Tested-by: Arnaldo Carvalho de Melo Cc: Josh Poimboeuf Link: http://lkml.kernel.org/r/1454296865-19749-1-git-send-email-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf thread: Fix reference count initial state

2015-12-14T15:08:55+00:00

We should always return from thread__new(), the constructor, with the object with a reference count of one, so that: struct thread *thread = thread__new(); thread__put(thread); Will call thread__delete(). If any reference is made to that 'thread' variable, it better use thread__get(thread) to hold a reference. We were returning with thread->refcnt set to zero, fix it and some cases where thread__delete() was being called, which were not a problem because just one reference was being used, now that we set it to 1, use thread__put() instead. Reported-by: Masami Hiramatsu Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-4b9mkuk66to4ecckpmpvqx6s@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf machine: Add method for common kernel_map(FUNCTION) operation

2015-09-30T21:34:29+00:00

And it is also a step in the direction of killing the separation of data and text maps in map_groups. Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-rrds86kb3wx5wk8v38v56gw8@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Add mispred-all config option to aid use with autofdo

2015-09-28T20:21:00+00:00

autofdo incorrectly expects branch flags to include either mispred or predicted. In fact mispred = predicted = 0 is valid and means the flags are not supported, which they aren't by Intel PT. To make autofdo work, add a config option which will cause Intel PT decoder to set the mispred flag on all branches. Below is an example of using Intel PT with autofdo. The example is also added to the Intel PT documentation. It requires autofdo (https://github.com/google/autofdo) and gcc version 5. The bubble sort example is from the AutoFDO tutorial (https://gcc.gnu.org/wiki/AutoFDO/Tutorial) amended to take the number of elements as a parameter. $ gcc-5 -O3 sort.c -o sort_optimized $ ./sort_optimized 30000 Bubble sorting array of 30000 elements 2254 ms $ cat ~/.perfconfig [intel-pt] mispred-all $ perf record -e intel_pt//u ./sort 3000 Bubble sorting array of 3000 elements 58 ms [ perf record: Woken up 2 times to write data ] [ perf record: Captured and wrote 3.939 MB perf.data ] $ perf inject -i perf.data -o inj --itrace=i100usle --strip $ ./create_gcov --binary=./sort --profile=inj --gcov=sort.gcov -gcov_version=1 $ gcc-5 -O3 -fauto-profile=sort.gcov sort.c -o sort_autofdo $ ./sort_autofdo 30000 Bubble sorting array of 30000 elements 2155 ms Note there is currently no advantage to using Intel PT instead of LBR, but that may change in the future if greater use is made of the data. Signed-off-by: Adrian Hunter Cc: Jiri Olsa Link: http://lkml.kernel.org/r/1443186956-18718-26-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Support generating branch stack

2015-09-28T19:59:14+00:00

Add support for generating branch stack context for PT samples. The decoder reports a configurable number of branches as branch context for each sample. Internally it keeps track of them by using a simple sliding window. We also flush the last branch buffer on each sample to avoid overlapping intervals. This is useful for: - Reporting accurate basic block edge frequencies through the perf report branch view - Using with --branch-history to get the wider context of samples - Other users of LBRs Also the Documentation is updated. Examples: Record with Intel PT: perf record -e intel_pt//u ls Branch stacks are used by default if synthesized so: perf report --itrace=ile is the same as: perf report --itrace=ile -b Branch history can be requested also: perf report --itrace=igle --branch-history Based-on-patch-by: Andi Kleen Signed-off-by: Adrian Hunter Cc: Jiri Olsa Link: http://lkml.kernel.org/r/1443186956-18718-15-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf intel-pt: Move branch filter logic

2015-09-28T19:58:27+00:00

intel_pt_synth_branch_sample() skips synthesizing if the branch does not match the branch filter. That logic was sitting in the middle of the function but is more efficiently placed at the start of the function, so move it. Signed-off-by: Adrian Hunter Cc: Jiri Olsa Link: http://lkml.kernel.org/r/1443186956-18718-14-git-send-email-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf auxtrace: Fix 'instructions' period of zero

2015-09-28T18:50:56+00:00

Instruction tracing options (i.e. --itrace) include an option for sampling instructions at an arbitrary period. e.g. --itrace=i10us means make an 'instructions' sample for every 10us of trace. Currently the logic does not distinguish between a period of zero and no period being specified at all, so it gets treated as the default period which is 100000. That doesn't really make sense. Fix it so that zero period is accepted and treated as meaning "as often as possible". In the case of Intel PT that is the same as a period of 1 and a unit of 'instructions' (i.e. --itrace=i1i). Signed-off-by: Adrian Hunter Cc: Jiri Olsa Link: http://lkml.kernel.org/r/1443186956-18718-2-git-send-email-adrian.hunter@intel.com [ Add a few lines describing this in the Documentation/intel-pt.txt file ] Signed-off-by: Arnaldo Carvalho de Melo

Merge tag 'perf-core-for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

2015-09-08T14:22:29+00:00

Pull perf/core improvements and fixes from Arnaldo Carvalho de Melo: User visible changes: - Use PERF_RECORD_SWITCH when available in intel-pt, instead of "sched:sched_switch" events, enabling an unprivileged user to trace multi-threaded or multi-process workloads. (Adrian Hunter) - Always use non inlined file name for 'srcfile' sort key. (Andi Kleen) - Quieten failed to read counter message, helps in systems without backend-stalled-cycles. (Andi Kleen) Infrastructure changes: - Add a 'perf test' entry for decoding of new x86 instructions. (Adrian Hunter) - Add new instructions (sha, clflushopt, clwb, pcommit, rdpkru, wrpkru, xsavec, xsaves, xrstors) to the x86 instruction decoder. (Adrian Hunter) - Add a build test to warn when source code drifts happen for the instruction decoder files in the kernel and in tools/perf. (Adrian Hunter) - Copy linux/filter.h to tools/include. (He Kuang) - Support function __get_dynamic_array_len in libtraceevent. (He Kuanguuu) - Tracing path finding/mounting/error reporting refactorings. (Jiri Olsa) - Store CPU socket and core IDs in perf.data. (Kan Liang) - Reorganize add/del probe insertion routines in 'perf probe'. (Namhyung Kim, Wang Nan) Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Ingo Molnar