linux/tools/rcu/rcu-updaters.sh
Paul E. McKenney 0ac55d095d tools/rcu: Add rcu-updaters.sh script
This commit adds a tools/rcu/rcu-updaters.sh script that uses bpftrace
to print a histogram of the RCU update-side primitives invoked during
the specified time interval, or until manually terminated if no interval
is specified.

Sample output on an idle laptop:

@counts[poll_state_synchronize_rcu]: 6
@counts[synchronize_srcu]: 13
@counts[call_rcu_tasks_trace]: 25
@counts[synchronize_rcu]: 54
@counts[kvfree_call_rcu]: 428
@counts[call_rcu]: 2134

Note that when run on a kernel missing one or more of the symbols, this
script will issue a diagnostic for each that is not found, but continue
normally for the rest of the functions.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
2024-06-06 11:44:42 -07:00

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#!/bin/sh
# SPDX-License-Identifier: GPL-2.0+
#
# Run bpftrace to obtain a histogram of the types of primitives used to
# initiate RCU grace periods. The count associated with rcu_gp_init()
# is the number of normal (non-expedited) grace periods.
#
# Usage: rcu-updaters.sh [ duration-in-seconds ]
#
# Note that not all kernel builds have all of these functions. In those
# that do not, this script will issue a diagnostic for each that is not
# found, but continue normally for the rest of the functions.
duration=${1}
if test -n "${duration}"
then
exitclause='interval:s:'"${duration}"' { exit(); }'
else
echo 'Hit control-C to end sample and print results.'
fi
bpftrace -e 'kprobe:kvfree_call_rcu,
kprobe:call_rcu,
kprobe:call_rcu_tasks,
kprobe:call_rcu_tasks_rude,
kprobe:call_rcu_tasks_trace,
kprobe:call_srcu,
kprobe:rcu_barrier,
kprobe:rcu_barrier_tasks,
kprobe:rcu_barrier_tasks_rude,
kprobe:rcu_barrier_tasks_trace,
kprobe:srcu_barrier,
kprobe:synchronize_rcu,
kprobe:synchronize_rcu_expedited,
kprobe:synchronize_rcu_tasks,
kprobe:synchronize_rcu_tasks_rude,
kprobe:synchronize_rcu_tasks_trace,
kprobe:synchronize_srcu,
kprobe:synchronize_srcu_expedited,
kprobe:get_state_synchronize_rcu,
kprobe:get_state_synchronize_rcu_full,
kprobe:start_poll_synchronize_rcu,
kprobe:start_poll_synchronize_rcu_expedited,
kprobe:start_poll_synchronize_rcu_full,
kprobe:start_poll_synchronize_rcu_expedited_full,
kprobe:poll_state_synchronize_rcu,
kprobe:poll_state_synchronize_rcu_full,
kprobe:cond_synchronize_rcu,
kprobe:cond_synchronize_rcu_full,
kprobe:start_poll_synchronize_srcu,
kprobe:poll_state_synchronize_srcu,
kprobe:rcu_gp_init
{ @counts[func] = count(); } '"${exitclause}"