diff options
| author | Frederic Weisbecker <fweisbec@gmail.com> | 2009-07-01 21:02:09 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-07-01 22:37:23 +0200 |
| commit | 0406ca6d8e849d9dd027c8cb6791448e81411aef (patch) | |
| tree | 3de38f9c75f41ec28b5b15b211f4e6df7ea7f437 /arch/x86 | |
| parent | 5da50258584469ddfee6545feb4eb2252a8d7e7b (diff) | |
perf_counter: Ignore the nmi call frames in the x86-64 backtraces
About every callchains recorded with perf record are filled up
including the internal perfcounter nmi frame:
perf_callchain
perf_counter_overflow
intel_pmu_handle_irq
perf_counter_nmi_handler
notifier_call_chain
atomic_notifier_call_chain
notify_die
do_nmi
nmi
We want ignore this frame as it's not interesting for
instrumentation. To solve this, we simply ignore every frames
from nmi context.
New example of "perf report -s sym -c" after this patch:
9.59% [k] search_by_key
4.88%
search_by_key
reiserfs_read_locked_inode
reiserfs_iget
reiserfs_lookup
do_lookup
__link_path_walk
path_walk
do_path_lookup
user_path_at
vfs_fstatat
vfs_lstat
sys_newlstat
system_call_fastpath
__lxstat
0x406fb1
3.19%
search_by_key
search_by_entry_key
reiserfs_find_entry
reiserfs_lookup
do_lookup
__link_path_walk
path_walk
do_path_lookup
user_path_at
vfs_fstatat
vfs_lstat
sys_newlstat
system_call_fastpath
__lxstat
0x406fb1
[...]
For now this patch only solves the problem in x86-64.
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Anton Blanchard <anton@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <1246474930-6088-1-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/stacktrace.h | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/perf_counter.c | 8 | ||||
| -rw-r--r-- | arch/x86/kernel/dumpstack_32.c | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/dumpstack_64.c | 22 |
4 files changed, 30 insertions, 8 deletions
diff --git a/arch/x86/include/asm/stacktrace.h b/arch/x86/include/asm/stacktrace.h index f517944b2b1..cf86a5e7381 100644 --- a/arch/x86/include/asm/stacktrace.h +++ b/arch/x86/include/asm/stacktrace.h @@ -3,6 +3,8 @@ extern int kstack_depth_to_print; +int x86_is_stack_id(int id, char *name); + /* Generic stack tracer with callbacks */ struct stacktrace_ops { diff --git a/arch/x86/kernel/cpu/perf_counter.c b/arch/x86/kernel/cpu/perf_counter.c index d4cf4ce19aa..36c3dc7b899 100644 --- a/arch/x86/kernel/cpu/perf_counter.c +++ b/arch/x86/kernel/cpu/perf_counter.c @@ -1561,6 +1561,7 @@ void callchain_store(struct perf_callchain_entry *entry, u64 ip) static DEFINE_PER_CPU(struct perf_callchain_entry, irq_entry); static DEFINE_PER_CPU(struct perf_callchain_entry, nmi_entry); +static DEFINE_PER_CPU(int, in_nmi_frame); static void @@ -1576,7 +1577,9 @@ static void backtrace_warning(void *data, char *msg) static int backtrace_stack(void *data, char *name) { - /* Process all stacks: */ + per_cpu(in_nmi_frame, smp_processor_id()) = + x86_is_stack_id(NMI_STACK, name); + return 0; } @@ -1584,6 +1587,9 @@ static void backtrace_address(void *data, unsigned long addr, int reliable) { struct perf_callchain_entry *entry = data; + if (per_cpu(in_nmi_frame, smp_processor_id())) + return; + if (reliable) callchain_store(entry, addr); } diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c index d593cd1f58d..bca5fba91c9 100644 --- a/arch/x86/kernel/dumpstack_32.c +++ b/arch/x86/kernel/dumpstack_32.c @@ -19,6 +19,12 @@ #include "dumpstack.h" +/* Just a stub for now */ +int x86_is_stack_id(int id, char *name) +{ + return 0; +} + void dump_trace(struct task_struct *task, struct pt_regs *regs, unsigned long *stack, unsigned long bp, const struct stacktrace_ops *ops, void *data) diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index d35db5993fd..54b0a327676 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -19,10 +19,8 @@ #include "dumpstack.h" -static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, - unsigned *usedp, char **idp) -{ - static char ids[][8] = { + +static char x86_stack_ids[][8] = { [DEBUG_STACK - 1] = "#DB", [NMI_STACK - 1] = "NMI", [DOUBLEFAULT_STACK - 1] = "#DF", @@ -33,6 +31,15 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, N_EXCEPTION_STACKS + DEBUG_STKSZ / EXCEPTION_STKSZ - 2] = "#DB[?]" #endif }; + +int x86_is_stack_id(int id, char *name) +{ + return x86_stack_ids[id - 1] == name; +} + +static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, + unsigned *usedp, char **idp) +{ unsigned k; /* @@ -61,7 +68,7 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, if (*usedp & (1U << k)) break; *usedp |= 1U << k; - *idp = ids[k]; + *idp = x86_stack_ids[k]; return (unsigned long *)end; } /* @@ -81,12 +88,13 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, do { ++j; end -= EXCEPTION_STKSZ; - ids[j][4] = '1' + (j - N_EXCEPTION_STACKS); + x86_stack_ids[j][4] = '1' + + (j - N_EXCEPTION_STACKS); } while (stack < end - EXCEPTION_STKSZ); if (*usedp & (1U << j)) break; *usedp |= 1U << j; - *idp = ids[j]; + *idp = x86_stack_ids[j]; return (unsigned long *)end; } #endif |