The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x 01b05fc0e5f3aec443a9a8ffa0022cbca2fd3608 # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024061354-playtime-clumsy-d741@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^..

Possible dependencies:

01b05fc0e5f3 ("rtla/timerlat: Fix histogram report when a cpu count is 0") ed774f7481fa ("rtla/timerlat_hist: Add timerlat user-space support") 2091336b9a8b ("rtla/timerlat_hist: Add auto-analysis support") 272ced2556e6 ("rtla: Add --house-keeping option") a957cbc02531 ("rtla: Add -C cgroup support") 9fa48a2477de ("rtla/timerlat: Add auto-analysis only option") 1f428356c38d ("rtla: Add hwnoise tool") ce6cc6f70cad ("Documentation/rtla: Add timerlat-top auto-analysis options") 5def33df84d2 ("rtla/timerlat: Add auto-analysis support to timerlat top")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 01b05fc0e5f3aec443a9a8ffa0022cbca2fd3608 Mon Sep 17 00:00:00 2001 From: John Kacur jkacur@redhat.com Date: Fri, 10 May 2024 15:03:18 -0400 Subject: [PATCH] rtla/timerlat: Fix histogram report when a cpu count is 0

On short runs it is possible to get no samples on a cpu, like this:

# rtla timerlat hist -u -T50

Index IRQ-001 Thr-001 Usr-001 IRQ-002 Thr-002 Usr-002 2 1 0 0 0 0 0 33 0 1 0 0 0 0 36 0 0 1 0 0 0 49 0 0 0 1 0 0 52 0 0 0 0 1 0 over: 0 0 0 0 0 0 count: 1 1 1 1 1 0 min: 2 33 36 49 52 18446744073709551615 avg: 2 33 36 49 52 - max: 2 33 36 49 52 0 rtla timerlat hit stop tracing IRQ handler delay: (exit from idle) 48.21 us (91.09 %) IRQ latency: 49.11 us Timerlat IRQ duration: 2.17 us (4.09 %) Blocking thread: 1.01 us (1.90 %) swapper/2:0 1.01 us ------------------------------------------------------------------------ Thread latency: 52.93 us (100%)

Max timerlat IRQ latency from idle: 49.11 us in cpu 2

Note, the value 18446744073709551615 is the same as ~0.

Fix this by reporting no results for the min, avg and max if the count is 0.

Link: https://lkml.kernel.org/r/20240510190318.44295-1-jkacur@redhat.com

Cc: stable@vger.kernel.org Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode") Suggested-by: Daniel Bristot de Oliveria bristot@kernel.org Signed-off-by: John Kacur jkacur@redhat.com Signed-off-by: Daniel Bristot de Oliveira bristot@kernel.org

diff --git a/tools/tracing/rtla/src/timerlat_hist.c b/tools/tracing/rtla/src/timerlat_hist.c index d4bab86ca1b9..fbe2c6549bf9 100644 --- a/tools/tracing/rtla/src/timerlat_hist.c +++ b/tools/tracing/rtla/src/timerlat_hist.c @@ -327,17 +327,29 @@ timerlat_print_summary(struct timerlat_hist_params *params, if (!data->hist[cpu].irq_count && !data->hist[cpu].thread_count) continue;

- if (!params->no_irq) - trace_seq_printf(trace->seq, "%9llu ", - data->hist[cpu].min_irq); + if (!params->no_irq) { + if (data->hist[cpu].irq_count) + trace_seq_printf(trace->seq, "%9llu ", + data->hist[cpu].min_irq); + else + trace_seq_printf(trace->seq, " - "); + }

- if (!params->no_thread) - trace_seq_printf(trace->seq, "%9llu ", - data->hist[cpu].min_thread); + if (!params->no_thread) { + if (data->hist[cpu].thread_count) + trace_seq_printf(trace->seq, "%9llu ", + data->hist[cpu].min_thread); + else + trace_seq_printf(trace->seq, " - "); + }

- if (params->user_hist) - trace_seq_printf(trace->seq, "%9llu ", - data->hist[cpu].min_user); + if (params->user_hist) { + if (data->hist[cpu].user_count) + trace_seq_printf(trace->seq, "%9llu ", + data->hist[cpu].min_user); + else + trace_seq_printf(trace->seq, " - "); + } } trace_seq_printf(trace->seq, "\n");

@@ -387,17 +399,29 @@ timerlat_print_summary(struct timerlat_hist_params *params, if (!data->hist[cpu].irq_count && !data->hist[cpu].thread_count) continue;

- if (!params->no_irq) - trace_seq_printf(trace->seq, "%9llu ", - data->hist[cpu].max_irq); + if (!params->no_irq) { + if (data->hist[cpu].irq_count) + trace_seq_printf(trace->seq, "%9llu ", + data->hist[cpu].max_irq); + else + trace_seq_printf(trace->seq, " - "); + }

- if (!params->no_thread) - trace_seq_printf(trace->seq, "%9llu ", - data->hist[cpu].max_thread); + if (!params->no_thread) { + if (data->hist[cpu].thread_count) + trace_seq_printf(trace->seq, "%9llu ", + data->hist[cpu].max_thread); + else + trace_seq_printf(trace->seq, " - "); + }

- if (params->user_hist) - trace_seq_printf(trace->seq, "%9llu ", - data->hist[cpu].max_user); + if (params->user_hist) { + if (data->hist[cpu].user_count) + trace_seq_printf(trace->seq, "%9llu ", + data->hist[cpu].max_user); + else + trace_seq_printf(trace->seq, " - "); + } } trace_seq_printf(trace->seq, "\n"); trace_seq_do_printf(trace->seq);