From 7d0dc9576dc3817c483b408715e506c3e9f37bed Mon Sep 17 00:00:00 2001 From: Daniel Bristot de Oliveira Date: Wed, 2 Mar 2022 20:01:39 +0100 Subject: rtla/timerlat: Add --dma-latency option Add the --dma-latency to set /dev/cpu_dma_latency to the specified value, this aims to avoid having exit from idle states latencies that could be influencing the analysis. Link: https://lkml.kernel.org/r/72ddb0d913459f13217086dadafad88a7c46dd28.1646247211.git.bristot@kernel.org Cc: Daniel Bristot de Oliveira Cc: Clark Williams Cc: Juri Lelli Cc: Jonathan Corbet Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google) --- Documentation/tools/rtla/common_timerlat_options.rst | 5 +++++ 1 file changed, 5 insertions(+) (limited to 'Documentation/tools/rtla') diff --git a/Documentation/tools/rtla/common_timerlat_options.rst b/Documentation/tools/rtla/common_timerlat_options.rst index 14a24a121f5d..bacdea6de7a3 100644 --- a/Documentation/tools/rtla/common_timerlat_options.rst +++ b/Documentation/tools/rtla/common_timerlat_options.rst @@ -21,3 +21,8 @@ Save the stack trace at the *IRQ* if a *Thread* latency is higher than the argument in us. + +**--dma-latency** *us* + Set the /dev/cpu_dma_latency to *us*, aiming to bound exit from idle latencies. + *cyclictest* sets this value to *0* by default, use **--dma-latency** *0* to have + similar results. -- cgit v1.2.3