From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
stable@vger.kernel.org,
"Srivatsa S. Bhat (VMware)" <srivatsa@csail.mit.edu>
Subject: [for-linus][PATCH 09/11] tracing/hwlat: Report total time spent in all NMIs during the sample
Date: Sun, 13 Oct 2019 13:43:51 -0400 [thread overview]
Message-ID: <20191013174419.549609687@goodmis.org> (raw)
In-Reply-To: <20191013174342.381019558@goodmis.org>
From: "Srivatsa S. Bhat (VMware)" <srivatsa@csail.mit.edu>
nmi_total_ts is supposed to record the total time spent in *all* NMIs
that occur on the given CPU during the (active portion of the)
sampling window. However, the code seems to be overwriting this
variable for each NMI, thereby only recording the time spent in the
most recent NMI. Fix it by accumulating the duration instead.
Link: http://lkml.kernel.org/r/157073343544.17189.13911783866738671133.stgit@srivatsa-ubuntu
Fixes: 7b2c86250122 ("tracing: Add NMI tracing in hwlat detector")
Cc: stable@vger.kernel.org
Signed-off-by: Srivatsa S. Bhat (VMware) <srivatsa@csail.mit.edu>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
kernel/trace/trace_hwlat.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/trace/trace_hwlat.c b/kernel/trace/trace_hwlat.c
index fa95139445b2..a0251a78807d 100644
--- a/kernel/trace/trace_hwlat.c
+++ b/kernel/trace/trace_hwlat.c
@@ -150,7 +150,7 @@ void trace_hwlat_callback(bool enter)
if (enter)
nmi_ts_start = time_get();
else
- nmi_total_ts = time_get() - nmi_ts_start;
+ nmi_total_ts += time_get() - nmi_ts_start;
}
if (enter)
--
2.23.0
next prev parent reply other threads:[~2019-10-13 17:44 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-13 17:43 [for-linus][PATCH 00/11] tracing: Fixes for v5.4-rc2 Steven Rostedt
2019-10-13 17:43 ` [for-linus][PATCH 01/11] tracefs: Revert ccbd54ff54e8 ("tracefs: Restrict tracefs when the kernel is locked down") Steven Rostedt
2019-10-13 17:43 ` [for-linus][PATCH 02/11] ftrace: Get a reference counter for the trace_array on filter files Steven Rostedt
2019-10-13 17:43 ` [for-linus][PATCH 03/11] tracing: Get trace_array reference for available_tracers files Steven Rostedt
2019-10-13 17:43 ` [for-linus][PATCH 04/11] tracing: Have trace events system open call tracing_open_generic_tr() Steven Rostedt
2019-10-13 17:43 ` [for-linus][PATCH 05/11] tracing: Add tracing_check_open_get_tr() Steven Rostedt
2019-10-13 17:43 ` [for-linus][PATCH 06/11] tracing: Add locked_down checks to the open calls of files created for tracefs Steven Rostedt
2019-10-13 17:43 ` [for-linus][PATCH 07/11] tracing: Do not create tracefs files if tracefs lockdown is in effect Steven Rostedt
2019-10-13 17:43 ` Steven Rostedt [this message]
2019-10-13 17:43 ` [for-linus][PATCH 10/11] tracing/hwlat: Dont ignore outer-loop duration when calculating max_latency Steven Rostedt
2019-10-13 17:43 ` [for-linus][PATCH 11/11] tracing: Initialize iter->seq after zeroing in tracing_read_pipe() Steven Rostedt
[not found] ` <20191013174419.228868312@goodmis.org>
2019-10-13 18:57 ` [for-linus][PATCH 08/11] recordmcount: Fix nop_mcount() function Steven Rostedt
2019-10-13 19:14 ` Uwe Kleine-König
2019-10-13 19:53 ` Steven Rostedt
2019-10-13 20:03 ` Steven Rostedt
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