diff options
| author | Dave Hansen <dave.hansen@linux.intel.com> | 2013-06-21 19:51:38 +0400 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2013-06-23 13:52:58 +0400 |
| commit | 0c4df02d739fed5ab081b330d67403206dd3967e (patch) | |
| tree | 37296c48ff5adef1537fd5c64977a3c1a0e8cff2 /arch/x86 | |
| parent | 14c63f17b1fde5a575a28e96547a22b451c71fb5 (diff) | |
| download | linux-0c4df02d739fed5ab081b330d67403206dd3967e.tar.xz | |
x86: Add NMI duration tracepoints
This patch has been invaluable in my adventures finding
issues in the perf NMI handler. I'm as big a fan of
printk() as anybody is, but using printk() in NMIs is
deadly when they're happening frequently.
Even hacking in trace_printk() ended up eating enough
CPU to throw off some of the measurements I was making.
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: paulus@samba.org
Cc: acme@ghostprotocols.net
Cc: Dave Hansen <dave@sr71.net>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/nmi.c | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/arch/x86/kernel/nmi.c b/arch/x86/kernel/nmi.c index e9bae4c2f2dd..0920212e6159 100644 --- a/arch/x86/kernel/nmi.c +++ b/arch/x86/kernel/nmi.c @@ -30,6 +30,9 @@ #include <asm/nmi.h> #include <asm/x86_init.h> +#define CREATE_TRACE_POINTS +#include <trace/events/nmi.h> + struct nmi_desc { spinlock_t lock; struct list_head head; @@ -108,11 +111,13 @@ static int __kprobes nmi_handle(unsigned int type, struct pt_regs *regs, bool b2 */ list_for_each_entry_rcu(a, &desc->head, list) { u64 before, delta, whole_msecs; - int decimal_msecs; + int decimal_msecs, thishandled; before = local_clock(); - handled += a->handler(type, regs); + thishandled = a->handler(type, regs); + handled += thishandled; delta = local_clock() - before; + trace_nmi_handler(a->handler, (int)delta, thishandled); if (delta < nmi_longest_ns) continue; |