Updated for systemd user units, fleshed out INSTALL.md

.gitignore

@@ -0,0 +1,12 @@
+*
+!.gitignore
+!CONFIGURE.md
+!INSTALL.md
+!README.md
+!psi-alerts-user.service
+!psi-alerts.sh
+!psi-alerts@.service
+!psi-by-example
+!psi-monitor-user.service
+!psi-monitor.service
+!psi-monitor.sh

CONFIGURE.md

@@ -0,0 +1,100 @@
+# CONFIGURE Included in this project are a number of systemd units:
+    * psi-monitor.service
+        * uses psi-monitor executable (in /usr/bin/)
+    * psi-alerts@.service (systemd template service)
+        * uses psi-alerts.sh script in */usr/local/bin/*
+    * psi-alerts-user.service (systemd user service)
+        * also uses psi-alerts.sh script in *~/bin/* (or wherever you want to
+          put it)
+
+The `psi-alerts.sh` is essentially a daemon (a systemd simple service), and for
+now the systemd template needs to be instantiated with the username that will
+execute `psi-alerts.sh` (if using the systemd template).  Also, a systemd unit
+override should be created, like so:  
+
+```
+sudo cp psi-alerts@.service /etc/systemd/system/
+sudo systemctl edit psi-alerts@<user>.service
+```
+--OR--
+```
+cp psi-alerts-user.service ~/.config/systemd/user/psi-alerts.service
+systemctl --user edit psi-alerts.service
+```
+This will open an editor, and in later versions of systemd the comment code will be included, clearly showing where the override should be entered:
+
+```
+### Editing /etc/systemd/system/psi-alerts@trey.service.d/override.conf
+### Anything between here and the comment below will become the contents of the drop-in file
+
+[Service]
+Environment=EMAIL_TO="email@domain.tld"
+Environment=SMS_DST="phone_number@sms.domain.tld"
+Environment=NOTIFICATION_CMD="dunstify"
+Environment=NOTIFICATION_OPTS="--timeout=0 --printid --urgency=critical --icon=/usr/share/icons/breeze-dark/emblems/16/emblem-warning.svg"
+Environment=NOTIFICATION_HIST_CMD="dunstctl history"
+Environment=NOTIFICATION_IDX=15
+Environment=SSH_USER="username"
+Environment=SSH_HOST="localhost"
+Environment=SSH_PORT=5999
+Environment=SSH_ID_PATH="~user/.ssh/psi-alerts"
+Environment=CLEAR_THRESHOLD="5.0"
+ExecStart=  # Clear ExecStart for user unit
+ExecStart=/path/to/psi-alerts.sh --user # User unit
+
+### Edits below this comment will be discarded
+
+### /etc/systemd/system/psi-alerts@.service
+# [Unit]
+# Description=Pressure Stall Information (PSI) alerts
+# PartOf=multi-user.target  # system template
+# PartOf=default.target     # user service
+# After=psi-monitor.service
+#
+# [Service]
+# 
+# User=%i # User unit will not have User=%i
+# Type=simple
+# ExecStart=psi-alerts.sh
+#
+# [Install]
+# WantedBy=multi-user.target
+```
+
+All of these are required except where noted, there are no default options
+(defaults may be added in the future).  A brief description of each:
+* **EMAIL_TO**:  the email address the notification should be sent to.  The
+  output of `pidstat` will be included in the body of this email, for each
+  triggered resource type (CPU, I/O, Memory), at the time the monitor alerted.
+* **SMS_DST**:  the email-to-SMS address, as defined by your mobile carrier.
+  Please review your mobile carrier's documentation.  For Google Fi, based in
+  the US, the format is
+  `<mobile_number_without_country_code>@msg.fi.google.com`.  This email address
+  does **not** get the output of `pidstat` in the body of the message.
+* **NOTIFICATION_CMD**:   The command on the remote host to run to display
+  notifications, e.g. `notify-send` or `dunstify`.
+* **NOTIFICATION_OPTS**:   Options for the `${NOTIFICATION_CMD}`.  Should
+  include `--print-id` if supported by the command.
+* **NOTIFICATION_HIST_CMD**:  The command to display the notification history
+  (e.g. `dunst history`).
+* **NOTIFICATION_IDX**:  The index if the JSON structure that contains the
+  notification ID.  `dunst`, as of version 1.9.2-1, displays its history as a
+  JSON structure.  For other notification daemons, some other history mechanism
+  will likely be required;  patches needed and welcome!
+* **SSH_USER**:  The SSH username to connect to the remote host that will
+  display the notifications to the system administrator.
+* **SSH_HOST**:  The SSH host to connect to.  This is where
+  `${NOTIFICATION_CMD} ${NOTIFICATION_OPTS}` and `${NOTIFICATION_HIST_CMD}`
+  will run.
+* **SSH_PORT**:  The SSH port to connect to.
+* **SSH_ID_PATH**:  The path to the SSH id (private key file) to use for
+  authenticating to the remote host.  This can be exluded if the local user
+  already has an ssh-agent running, with the necessary key and passphrase
+  entered.  If ssh-agent is not desired, then this SSH id (private key file)
+  should have an empty passphrase (i.e., no passphrase).  Not having this
+  environment variable, and no ssh-agent will disable the desktop notifications
+  (SMS and email will still work, as they don't use SSH)
+* **CLEAR_THRESHOLD**:  The percentage threshold the some avg300 threshold
+  should be below before considering the alert cleared.  This will depend
+  highly on the workload running on the system.
+

INSTALL.md

@@ -0,0 +1,63 @@
+# INSTALL
+First, clone this repository with the `--recurse-submodules` flag:
+```
+$ git clone --recurse-submodules https://git.eldon.me/trey/psi-alerts.git
+```
+
+`--recurse-submodules` is only necessary if you wish to use the modified
+psi-by-example program for `psi-monitor`.  I found this too noisy to be of use,
+it alerts too quickly so I wrote my own with relaxed timing.
+
+If you want to use the psi-by-example/psi-monitor code, you'll need to compile
+it: 
+
+```
+gcc -o psi-monitor psi-monitor.c
+``` 
+
+## Using the systemd template unit
+1.  Copy the `psi-alerts.sh` and `psi-monitor.sh` scripts to */usr/local/bin*:
+
+    ```
+    sudo cp psi-alerts.sh /usr/local/bin
+    sudo cp psi-monitor.sh /usr/local/bin/psi-monitor 
+    ### OR ###
+    sudo cp psi-by-example/psi-monitor /usr/local/bin
+    ```
+
+2.  Copy the systemd units to */etc/systemd/system*:
+
+    ```
+    sudo cp psi-alerts@.service psi-monitor.service /etc/systemd/system/
+    ```
+
+
+## Using the systemd user units
+1.  Copy the `psi-alerts.sh` and `psi-monitor.sh` scripts to *~/bin* (or
+    wherever you want them):
+    
+    ```
+    cp -a psi-alerts.sh psi-monitor.sh ~/bin/
+    ```
+
+2.  Copy the systemd user units to *~/.config/systemd/user/*
+
+    ```
+    cp psi-alerts-user.service ~/.config/systemd/user/psi-alerts.service
+    cp psi-monitor-user.service ~/.config/systemd/user/psi-monitor.service
+    ```
+
+# CONFIGURE
+See *CONFIGURE.md* in this repository
+
+# ENABLE and START
+## system template instance:
+```
+sudo systemctl enable --now psi-monitor.service psi-alerts@<user>.service
+```
+
+## User instance
+```
+systemctl --user enable --now psi-monitor.service psi-alerts.service
+```
+

README.md

@@ -2,28 +2,102 @@
 ## PURPOSE
 
 This project aims to deliver Pressure Stall Information (PSI) alerts via
-standard Linux graphical desktop (through `libnotify` compatible daemons and
-CLI programs), and email (email-to-SMS is also supported).  This can alert the
-system administrator of CPU, I/O, or Memory (RAM) pressure in near real time.
+standard Linux graphical desktop notifications (through `libnotify` compatible
+daemons and CLI programs), and email (email-to-SMS is also supported).  This
+can alert the system administrator of CPU, I/O, or Memory (RAM) pressure in
+near real time.
 
 ## PREREQUISITES
-* A Linux system with kernel 5.2.0 or greater
+* A Linux system with kernel 5.2.0 or greater, with the /proc filesystem
+  enabled
 * systemd
 * zsh
+* sysstat (for pidstat)
 * ssh (OpenSSH, for desktop notifications)
 * psi-by-example (a modified version of this is included in this project as a
   submodule)
+* a libnotify-compatible desktop notification system
+    * any notification program should use the `--print-id` parameter if
+      possible
+        * both `notify-send` and `dunstify` (part of
+          [dunst](https://dunst-project.org/)) support this
+    * note, this has only been tested with `dunst`, since it has the capability
+      of showing notification history
+        * `notify-send` specifically does not appear to retain a history, so the
+          `check_dunst_id_is_visible` function won't work with it (and the logic to
+          skip sending a new notification if one is already sent will be broken).  
+            * since I don't use `notify-send`, I'm not sure how to solve this
+            * patches welcome!
+* jq (for the aformentioned `dunst` integration)
+
+## History
+
+When I first learned about [Pressure Stall
+Information](https://docs.kernel.org/accounting/psi.html) (PSI), I was
+intrigued.  This provides a real-time view into the performance and typical
+resource contention Linux system administrators need to worry about:  CPU, I/O,
+and Memory (RAM).  During this research, I found [this
+post](https://unixism.net/2019/08/linux-pressure-stall-information-psi-by-example/)
+complete with a C code example;  albeit, it was light on I/O details and the
+example C code the author provided didn't even include Memory pressure at all
+(so modified it to include Memory pressure).  
+
+A quick and dirty description of PSI:  whenever one or more processes are
+waiting for some measurable resource (CPU, I/O, or RAM), the percentage of
+processes waiting on the resource will begin to increase.  Initially, the
+percentage will be low, but as resource contention increases, more and more
+processes will be waiting to be processed by the CPU for that resource.  If not
+all processes are waiting on this resource, PSI calls this the "some"
+contention for resources.  If all processes are waiting on the resource, this
+is known as the "full" resource contention.  
+
+The pressure information is exposed in the _/proc_ filesystem in these three
+virtual files: _/proc/pressure/cpu_, _/proc/pressure/io_,
+_/proc/pressure/memory_.  Each file reports both some and full, and has the
+following output:
 
-## INSTALL
-First, clone this repository with the `--recurse-submodules` flag:
 ```
-$ git clone --recurse-submodules https://git.eldon.me/trey/psi-alerts.git
+some avg10=0.02 avg60=0.43 avg300=0.55 total=711489361
+full avg10=0.02 avg60=0.43 avg300=0.54 total=681874430
 ```
 
-## CONFIGURE
-Included in this project are a number of systemd units:
-    * psi-monitor.service
-    * psi-alerts@.service (template service)
+This example is taken from _/proc/pressure/io_, for I/O pressure.   The full
+CPU pressure information really depends on the cgroups, which this project
+doesn't pay close attention to at this time.  The percentages are a measure of
+the average resource pressure over the last 10s, 60s, and 300s (5 minutes).
+The total is the number of microseconds that any processes were waiting for the
+resource;  this is a counter that is reset on boot, and will continously update
+as processes wait for the resource.  They always have to wait for the resource,
+even if it's on the order of hundreds of microseconds or less.  Even if the
+percentages were all zeroes, the total counter will be nonzero (at least for
+the some metrics), and even the full metrics will have a nonzero total except
+for CPU, because the full CPU total only really applies to cgroups (and are out
+of scope for this project at present).
+
+The monitor code (from psi-by-example listed above) only considers the "some"
+pressure for all three resources, which will usually alert before the system
+becomes critical (and in the case of full Memory usage/thrashing, completely
+unusable for any workload).  Thus the alerts should come in well before the full
+resource pressure gets maxed out.
+
+Now, I don't know C very well, but this _monitor.c_ code was easy enough to
+extend to include memory pressure.  However, the _create_load.c_ only creates
+CPU and I/O load (memory load is too detrimental to system performance).  
+
+This was developed on an [SSDNodes VPS](https://ssdnodes.com) (Virtual Private
+Server), which is a KVM virtual machine, backed by SSD hardware.  It is very
+well provisioned with virtual hardware:  8 vCPUs, 32GiB RAM, and 640GiB SSD
+disk space.  Currently, there is very little load on this system, even with
+four different websites on it, with corresponding database engines, and an
+nginx reverse proxy.  I plan on putting
+[mailcow-dockerized](https://docs.mailcow.email/) on this VPS soon, which has
+the potential to increase the load significantly.
+
+Now, once the regular workload of this VPS increases, my current configuration
+may become too noisy.  However, I've tried to configure `psi-alerts.sh` in such
+a way that it only alerts once when the pressure on a resource increases, and
+won't alert again until that pressure subsides (and the some percentages drop
+below the configurable threshold for at least five minutes).
 
 ## TODO
 * finish INSTALL section
@@ -33,3 +107,13 @@ Included in this project are a number of systemd units:
     * about defining an instance and editing it
         * `sudo systemctl edit psi-alerts@<user>.service`
         * mainly for `Environment=` variables
+    * consider reworking this for a user service, not a system service
+        * this could make desktop notifications simpler, and not having to use
+          SSH keys without passphrases
+          * possibly learn how to connect to an existing ssh-agent
+        * need to become much more familiar with user services
+* consider reworking all code in a compiled language (other than C)
+    * time to learn Go
+    * or continue learning Rust
+    * need to know how to use kernel syscalls in these languages (if possible)
+    * also, convert psi-alerts.sh script to either of these languages

psi-alerts-user.service

@@ -0,0 +1,12 @@
+[Unit]
+Description=Pressure Stall Information (PSI) alerts
+PartOf=default.target
+After=psi-monitor.service
+
+[Service]
+Type=simple
+ExecStart=psi-alerts.sh
+
+[Install]
+WantedBy=default.target
+

psi-alerts.sh

@@ -1,8 +1,9 @@
 #!/usr/bin/env zsh
 
+################################################################################
 # Send alerts when Pressure Stall Information is high
 # 
-#    Copyright © 2023 Trey Blancher
+#    Copyright © 2023 Trey Blancher $(base64 -d <<< dHJleUBibGFuY2hlci5uZXQK)
 #
 #    This program is free software: you can redistribute it and/or modify it
 #    under the terms of the GNU General Public License as published by the Free
@@ -17,6 +18,9 @@
 #    You should have received a copy of the GNU General Public License along
 #    with this program.  If not, see <https://www.gnu.org/licenses/>.
 #
+#    Submodules may be distributed under a separate software license;  see the
+#    LICENSE file within each submodule.
+# 
 # This script monitors the systemd journal, specifically the
 # `psi-monitor.service` and waits for Pressure State Information monitor events
 # to be logged.  The monitor program is shipped in the psi-by-example submodule
@@ -32,51 +36,85 @@
 # systemd psi-alerts@<user>.service overrides (will be placed in
 # /etc/systemd/system/psi-alerts@<user>.service.d/override.conf. See the
 # README.md for details.
-
+################################################################################
 
 svc="psi-monitor.service"
 cpu="/proc/pressure/cpu"
 mem="/proc/pressure/memory"
 io="/proc/pressure/io"
+user="$(whoami)"
 host="$(hostname)"
 email_to="${EMAIL_TO}"
 sms_dst="${SMS_DST}"
 sms_domain="$(awk -F@ '{print $NF}' <<< ${SMS_DST})"
 ssh_port="${SSH_PORT}"
 ssh_host="${SSH_HOST}"
+ssh_user="${SSH_USER}"
+ssh_id_path="${SSH_ID_PATH}"
 clear_threshold="${CLEAR_THRESHOLD}"
 notification_cmd="${NOTIFICATION_CMD}"
+notification_hist_cmd="${NOTIFICATION_HIST_CMD}"
 notification_opts="${NOTIFICATION_OPTS}"
 id_idx="${NOTIFICATION_IDX}"
+user=false
 
+if [[ -n "${1}" ]]; then
+    if  [[ "${1}" == "-u" ]] || \
+        [[ "${1}" == "--user" ]]; then
+        user=true
+    fi 
+fi
+       
+get_ssh_agent () {
+    for dir in /tmp/ssh-*; do
+        if [[ -O ${dir} ]]; then
+            # only choose the last agent
+            export SSH_AGENT_PID=$(ps -eaf | grep '[s]sh-agent' | \
+                                   grep ${user} | awk '{print $2}')
+            export SSH_AUTH_SOCK=$(ls ${dir}/agent.* | tail -1)
+        fi
+    done
+
+    if [[ -S ${SSH_AUTH_SOCK} ]]; then
+        # we found an ssh_agent socket
+        true
+    else
+        false
+    fi
+}
 print_psi () {
     local psi_file="${1}"
-    cat "${(P)psi_file}"
+    cat "${(P)$(tr '[[:upper:]]' '[[:lower:]]' <<< "${psi_file}")}"
 }
 
-print_pidstat () {
+print_stats () {
     local psi_type="${1}"
-    local opts="-l --human"
 
     case "${psi_type}" in
         CPU)
-            opts="-u ${opts}"
+            top -bcn1 -o %CPU -w 512 | head -n 30
+            printf "\n\n"
+            pidstat -ul --human
             ;;
         IO)
-            opts="-d ${opts}"
+            sudo iotop --batch --only --iter=10
+            printf "\n\n"
+            pidstat -dl --human
             ;;
         MEM)
-            opts="-r ${opts}"
+            top -bcn1 -o %MEM -w 512 | head -n 30
+            printf "\n\n"
+            pidstat -rl --human
             ;;
         *)
             print "Invalid psi_type:  ${psi_type}" >&2
             ;;
     esac
-
-    pidstat "${opts}"
 }
 
+
 send_notice () {
+    #set -x
     local psi_type="${1}"
     shift
     
@@ -96,19 +134,35 @@ send_notice () {
     esac
 
     integer notification_id
-    if ! notification_id=$(ssh -q "${ssh_host}" -p ${ssh_port} \
+    if get_ssh_agent && [[ -S ${SSH_AUTH_SOCK} ]]; then
+        if ! notification_id=$(ssh -q "${ssh_user}@${ssh_host}" -p ${ssh_port} \
             "${notification_cmd} ${notification_opts} '${host}:  PSI ${psi_type} triggered!' '${psi}'"); then
                 print "Connection to notification daemon failed!" >&2
                 false
         else
-        echo ${notification_id}
+            print ${notification_id}
             true
         fi
+    elif [[ -n "${ssh_id_path}" ]]; then
+        if ! notification_id=$(ssh -q -i "${ssh_id_path}" "${ssh_user}@${ssh_host}" -p ${ssh_port} \
+            "${notification_cmd} ${notification_opts} '${host}:  PSI ${psi_type} triggered!' '${psi}'"); then
+                print "Connection to notification daemon failed!" >&2
+                false
+        else
+            print ${notification_id}
+            true
+        fi
+    else
+        print "No SSH notifications configured.  Returning." >&2
+        false
+    fi
+    #set +x
 }
 
 send () {
+    #set -x
     if [[ "${#@}" -lt 2 ]] && [[ "${#@}" -gt 3 ]]; then
-        echo "Wrong number of arguments to send()!" >&2
+        print "Wrong number of arguments to send()!" >&2
         return false
     fi
 
@@ -128,47 +182,51 @@ send () {
 
     local psi="$(print_psi $(tr '[[:upper:]]' '[[:lower:]]' <<< ${psi_type}))"
 
-    local subj="PSI on deltachunk ${psi_type} triggered!"
 
-
-    local body="Pressure Stall Information triggered on ${psi_type} at $(date +'%FT%T %Z')"
+    local email=$(mktemp /tmp/psi.eml.XXXX.txt)
+    local subj
+    printf "Pressure Stall Information for ${host} triggered on ${psi_type} at $(date +'%FT%T %Z')\n\n" > ${email}
     if [[ -n "${current_alarms}" ]]; then
-        body="${body}\nMultiple alarms triggered:  ${current_alarms}"
-        # if this is not an SMS, include pidstat info
-        if [[ ! "${dst}" =~ "${sms_domain}" ]]; then
+        current_alarms="${current_alarms}|${psi_type}"
+        subj="PSI on ${host} ${current_alarms} triggered!"
+        printf "Multiple alarms triggered:  ${current_alarms}\n\n" >> ${email}
+    else
+        subj="PSI on ${host} ${psi_type} triggered!"
+        current_alarms="${psi_type}"
+    fi
+    print_psi "${psi_type}" >> ${email}
+    printf "\n\n" >> ${email}
+    # is this an email or SMS?
+    if [[ ! "${dst}" =~ "@${sms_domain}" ]]; then
         for p in $(tr '|' ' ' <<< "${current_alarms}"); do
-                body="${body}\n\n$(print_pidstat ${p})"
+            printf "\n\nStatistics info for ${p}\n\n" >> ${email}
+            print_stats "${p}" >> ${email}
+            printf "\n\n" >> ${email}
         done
     fi
-    fi
 
+    # send the message
+    (
+       printf "To:  ${dst}\n"
+       printf "Subject:  ${subj}\n"
+       cat ${email}
+    ) | sendmail -t
          
-    local email=$(mktemp /tmp/psi.eml.XXXX)
-
-    cat <<-EOF > ${email}
-        ${body}
-
-EOF
-
-
-    /usr/bin/mail --resource-files=/ \
-                  --subject="${subj}" \
-                  --end-options \
-                  ${dst} < ${email}
+    #set +x
 }
 
 is_clear () {
     local psi_type="${1}"
     local psi_file="$(tr '[[:upper:]]' '[[:lower:]]' <<< "${psi_type}")"
 
-    local avg10=$(grep some "${(P)psi_file}" | awk '{print $2}' | awk -F= '{print $2}')
+    local avg300=$(grep some "${(P)psi_file}" | awk '{print $4}' | awk -F= '{print $2}')
     local prev=$(grep some "${(P)psi_file}" | awk '{print $5}' | awk -F= '{print $2}')
 
     
-    if [[ ${avg10} -lt ${clear_threshold} ]]; then
-        return 0
+    if [[ ${avg300} -lt ${clear_threshold} ]]; then
+        true
     else
-        return 1
+        false
     fi
 }
 
@@ -186,7 +244,7 @@ exec_notices () {
                 send "${psi_type}" "${current_alarms}" "${email_to}"
                 ;;
             *)
-                echo "Something went wrong!" >&2
+                print "Something went wrong!" >&2
                 false
                 ;;
         esac
@@ -203,39 +261,73 @@ check_dunst_id_is_visible () {
     local dunst_id="${1}"
 
     typeset -a ids
-    if ids=$(ssh -q "${ssh_host}" -p ${ssh_port} \
-        "dunstctl history | jq '.data[0][][${id_idx}].data'"); then
-            echo "Connection to dunst failed!" >&2
+    if ! ids=$(ssh -q "${ssh_host}" -p ${ssh_port} -l "${ssh_user}" \
+        "${notification_hist_cmd} | jq '.data[0][].id.data'"); then
+        if ! ids=$(ssh -qi "${ssh_id_path}" -p ${ssh_port} -l "${ssh_user}" \
+            "${ssh_host}" "${notification_hist_cmd} | jq '.data[0][].id.data'"); then
+                print "Connection to dunst failed!" >&2
                 return 2
         fi
+    fi
 
+    # if the alert is visible, it's not in the dunst history
     if grep -qP "\b${dunst_id}\b" <<< "${ids}"; then
-        true
-    else
         false
+    else
+        true
     fi
 }
-#set -x
+
 local current_alarm=""
-local last_alarm=""
 typeset -A notice_sent
 typeset -A secs
 integer last_dunst_id=-1
+local last_line=""
 
-journalctl -b 0 -fu "${svc}"  | \
-while read line; do
+#set -x
+while true; do
+    if ${user}; then
+        line=$(journalctl --user -u ${svc} -n1)
+    else
+        line=$(journalctl -u ${svc} -n1)
+    fi
+    now=$(date +%s)
+    last_timestamp=$(date -d "$(awk '{print $1" "$2" "$3}' <<< "${line}")" +%s)
+    time_diff=$(( now - last_timestamp ))
+    if [[ "${last_line}" == "${line}" ]]; then
+        # last line hasn't changed, check to see if we can clear alarms
+        if (( time_diff >= 3 )); then
+            # haven't seen a monitor alert for 3 seconds, see if we can clear them
+            if [[ -n "${current_alarms}" ]]; then
+                typeset -a alarms=( $(tr '|' ' ' <<< "$current_alarms") )
+                for alarm in ${alarms}; do
+                    integer elapsed=$(( now - ${secs[${alarm}]} ))
+                    if is_clear "${alarm}" && (( elapsed >= 300 )); then
+                        current_alarms=$(sed -E "s/${alarm}\|?//; s/|$//" <<< "${current_alarms}")
+                        unset "notice_sent[${alarm}]"
+                        unset "secs[${alarm}]"
+                    fi
+                done
+            fi
+            sleep 1
+            continue
+        fi
+    
+        sleep 1
+        continue
+    fi
+    last_line="${line}"
+    if (( time_diff < 3 )); then
         local psi_type="$(grep -Eo "(CPU|MEM|IO) PSI event" <<< "${line}" | grep -Eo "CPU|MEM|IO")"
         if [[ -n "${psi_type}" ]]; then
-        secs+=(${psi_type} $(date +%s))
-        if [[ "${psi_type}" != "${last_alarm}" ]]; then
+            secs+=(${psi_type} ${now})
             if [[ ! ${notice_sent[${psi_type}]} ]]; then
                 last_dunst_id=$(exec_notices "${psi_type}" "${current_alarms}")
                 notice_sent+=(${psi_type} true)
-            elif (( last_dunst_id >= 0 )) && ! check_dunst_id_is_visible "${last_dunst_id}"; then
+            elif (( last_dunst_id >= 0 )) && check_dunst_id_is_visible "${last_dunst_id}"; then
+                sleep 1
                 continue
             fi
-        fi
-        last_alarm="${psi_type}"
             if [[ -z "${current_alarms}" ]]; then
                 current_alarms="${psi_type}"
             else
@@ -243,16 +335,9 @@ while read line; do
                     current_alarms="${current_alarms}|${psi_type}"
                 fi
             fi
-    else
-        typeset -a alarms=( $(tr '|' ' ' <<< "$current_alarms") )
-        for alarm in ${alarms}; do
-            integer elapsed=$(( $(date +%s) - ${secs[${alarm}]} ))
-            if is_clear "${alarm}" && (( elapsed > 300 )); then
-                current_alarms=$(sed -E "s/${alarm}\|?//" <<< "${current_alarms}")
-                last_alarm=$(awk -F'|' '{print $NF}' <<< "${current_alarms}")
         fi
-        done
     fi
+    sleep 1
 done
 #set +x
 

psi-monitor-user.service

@@ -0,0 +1,10 @@
+[Unit]
+Description=Pressure Stall Information (PSI) Monitor
+PartOf=default.target
+
+[Service]
+Type=simple
+ExecStart=/home/trey/bin/psi-monitor.sh 80
+
+[Install]
+WantedBy=default.target

psi-monitor.sh

@@ -0,0 +1,62 @@
+#!/usr/bin/env zsh
+#
+# Pressure Stall Information monitor
+#
+#    Copyright © 2023 Trey Blancher $(base64 -d <<< dHJleUBibGFuY2hlci5uZXQK)
+#
+#    This program is free software: you can redistribute it and/or modify it
+#    under the terms of the GNU General Public License as published by the Free
+#    Software Foundation, either version 3 of the License, or (at your option)
+#    any later version.
+#
+#    This program is distributed in the hope that it will be useful, but
+#    WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
+#    or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
+#    for more details.
+#
+#    You should have received a copy of the GNU General Public License along
+#    with this program.  If not, see <https://www.gnu.org/licenses/>.
+#
+#    Submodules may be distributed under a separate software license;  see the
+#    LICENSE file within each submodule.
+# 
+# This script monitors the three pressure stall information files
+# /proc/pressure{cpu,io,memory} and reports if any resource is above threshold
+# for the "some" values.  It takes an optional single argument, the threshold at
+# which to alert.  If this is not supplied, it defaults to a threshold of 30.0 
+# percent.
+#
+
+local cpu="/proc/pressure/cpu"
+local cpu_ctr=0
+local io="/proc/pressure/io"
+local io_ctr=0
+local mem="/proc/pressure/memory"
+local mem_ctr=0
+local threshold=30.0
+
+if [[ -n "${1}" ]]; then
+    threshold=${1}
+fi
+
+# main loop
+while true; do
+    local cpu_pct=$(grep 'some' ${cpu} | awk '{print $2}' | awk -F'=' '{print $2}')    
+    local io_pct=$(grep 'some' ${io} | awk '{print $2}' | awk -F'=' '{print $2}')    
+    local mem_pct=$(grep 'some' ${mem} | awk '{print $2}' | awk -F'=' '{print $2}')    
+    
+    if (( cpu_pct > threshold )); then
+        cpu_ctr=$(( ${cpu_ctr} + 1 ))
+        printf "CPU PSI event %d triggered.\n" ${cpu_ctr}
+    fi
+    if (( io_pct > threshold )); then
+        io_ctr=$(( ${io_ctr} + 1 ))
+        printf "IO PSI event %d triggered.\n" ${io_ctr}
+    fi
+    if (( mem_pct > threshold )); then
+        mem_ctr=$(( ${mem_ctr} + 1 ))
+        printf "MEM PSI event %d triggered.\n" ${mem_ctr}
+    fi
+
+    sleep 10
+done