Performance: Mark channel and buffer event disabled check unlikely

Channel and buffer are typically enabled when tracing, else the probes
would not be connected. Ensure the compiler optimizes for the right
usual case.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

diff --git a/libringbuffer/frontend_api.h b/libringbuffer/frontend_api.h
index 93f6760b28b938238171dda1cb3bd395352d362e..5ddb8ac460951f0bae59a3f098cf6bca510a3799 100644 (file)
--- a/libringbuffer/frontend_api.h
+++ b/libringbuffer/frontend_api.h
@@ -160,14 +160,14 @@ int lib_ring_buffer_reserve(const struct lttng_ust_lib_ring_buffer_config *confi
        unsigned long o_begin, o_end, o_old;
        size_t before_hdr_pad = 0;
 
-       if (uatomic_read(&chan->record_disabled))
+       if (caa_unlikely(uatomic_read(&chan->record_disabled)))
                return -EAGAIN;
 
        if (config->alloc == RING_BUFFER_ALLOC_PER_CPU)
                buf = shmp(handle, chan->backend.buf[ctx->cpu].shmp);
        else
                buf = shmp(handle, chan->backend.buf[0].shmp);
-       if (uatomic_read(&buf->record_disabled))
+       if (caa_unlikely(uatomic_read(&buf->record_disabled)))
                return -EAGAIN;
        ctx->buf = buf;