diff options
| author | Steven Rostedt <srostedt@redhat.com> | 2009-03-17 18:09:55 -0400 |
|---|---|---|
| committer | Steven Rostedt <srostedt@redhat.com> | 2009-03-17 23:10:35 -0400 |
| commit | af4617bdba34aa556272b34c3986b0a4d588f568 (patch) | |
| tree | c46a6b695724ee27c0113f6affcebeffcefbcf23 | |
| parent | 37886f6a9f62d22530ffee8d3f9215c8345b6969 (diff) | |
tracing: add global-clock option to provide cross CPU clock to traces
Impact: feature to allow better serialized clock
This patch adds an option called "global-clock" that will allow
the tracer to switch to a slower but more accurate (across CPUs)
clock.
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
| -rw-r--r-- | kernel/trace/trace.c | 34 | ||||
| -rw-r--r-- | kernel/trace/trace.h | 1 |
2 files changed, 31 insertions, 4 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 3be2f788e10..2f994caab0b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -315,6 +315,7 @@ static const char *trace_options[] = { "printk-msg-only", "context-info", "latency-format", + "global-clock", NULL }; @@ -2251,6 +2252,34 @@ static int set_tracer_option(struct tracer *trace, char *cmp, int neg) return 0; } +static void set_tracer_flags(unsigned int mask, int enabled) +{ + /* do nothing if flag is already set */ + if (!!(trace_flags & mask) == !!enabled) + return; + + if (enabled) + trace_flags |= mask; + else + trace_flags &= ~mask; + + if (mask == TRACE_ITER_GLOBAL_CLK) { + u64 (*func)(void); + + if (enabled) + func = trace_clock_global; + else + func = trace_clock_local; + + mutex_lock(&trace_types_lock); + ring_buffer_set_clock(global_trace.buffer, func); + + if (max_tr.buffer) + ring_buffer_set_clock(max_tr.buffer, func); + mutex_unlock(&trace_types_lock); + } +} + static ssize_t tracing_trace_options_write(struct file *filp, const char __user *ubuf, size_t cnt, loff_t *ppos) @@ -2278,10 +2307,7 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, int len = strlen(trace_options[i]); if (strncmp(cmp, trace_options[i], len) == 0) { - if (neg) - trace_flags &= ~(1 << i); - else - trace_flags |= (1 << i); + set_tracer_flags(1 << i, !neg); break; } } diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h index b0ecad8ecc3..26a7a28ca11 100644 --- a/kernel/trace/trace.h +++ b/kernel/trace/trace.h @@ -667,6 +667,7 @@ enum trace_iterator_flags { TRACE_ITER_PRINTK_MSGONLY = 0x10000, TRACE_ITER_CONTEXT_INFO = 0x20000, /* Print pid/cpu/time */ TRACE_ITER_LATENCY_FMT = 0x40000, + TRACE_ITER_GLOBAL_CLK = 0x80000, }; /* |