WIP

desktop-app/app/components/DeviceManager/index.js

@@ -9,6 +9,7 @@ import CloseIcon from '@material-ui/icons/Close';
 import AddIcon from '@material-ui/icons/Add';
 import Dialog from '@material-ui/core/Dialog';
 import AppBar from '@material-ui/core/AppBar';
+import Alert from '@material-ui/lab/Alert';
 import Toolbar from '@material-ui/core/Toolbar';
 import Typography from '@material-ui/core/Typography';
 import {DragDropContext, Droppable, Draggable} from 'react-beautiful-dnd';
@@ -16,6 +17,7 @@ import LightBulbIcon from '../icons/LightBulb';
 import DeviceList from './DeviceList';
 import AddDeviceContainer from '../../containers/AddDeviceContainer';
 import ErrorBoundary from '../ErrorBoundary';
+import {recommendedMaxNumberOfDevices} from '../../utils/deviceManagerUtils';
 
 import styles from './styles.css';
 
@@ -29,6 +31,8 @@ function DeviceManager(props) {
     inactiveFiltered: [],
   });
 
+  const [maxDevicesWarning, setMaxDevicesWarning] = useState(false);
+
   useEffect(() => {
     const activeDevices = props.browser.devices;
     const activeDevicesById = activeDevices.reduce((acc, val) => {
@@ -36,6 +40,8 @@ function DeviceManager(props) {
       return acc;
     }, {});
 
+    setMaxDevicesWarning(activeDevices.length >= recommendedMaxNumberOfDevices);
+
     const currentInactiveDevicesById = devices.inactive.reduce((acc, val) => {
       acc[val.id] = val;
       return acc;
@@ -104,6 +110,7 @@ function DeviceManager(props) {
   const updateDevices = devices => {
     const active = [...devices.active];
     const inactive = [...devices.inactive];
+    setMaxDevicesWarning(active.length >= recommendedMaxNumberOfDevices);
     setDevices({active, inactive});
     props.setActiveDevices(active);
   };
@@ -133,6 +140,12 @@ function DeviceManager(props) {
             </Toolbar>
           </AppBar>
           <div className={styles.container}>
+            {maxDevicesWarning && (
+              <Alert severity="warning" className={classes.maxDevicesWarning}>
+                Adding more than {recommendedMaxNumberOfDevices} devices may
+                slow down the system.
+              </Alert>
+            )}
             <Typography variant="body1" className={classes.toolTip}>
               <span>✨</span>Drag and drop the devices across to re-order them.
             </Typography>
@@ -190,6 +203,10 @@ const useStyles = makeStyles(theme => ({
     color: theme.palette.text.primary,
     width: 'fit-content',
   },
+  maxDevicesWarning: {
+    position: 'absolute',
+    top: '80px',
+  },
 }));
 
 export default DeviceManager;

desktop-app/app/utils/deviceManagerUtils.js

@@ -0,0 +1,59 @@
+import os from 'os';
+import {SSL_ERROR_CODES} from '../constants/values';
+import childProcess from 'child_process';
+
+export const MIN_NUMBER_OF_DEVICES = 2;
+
+function exec(command) {
+  const output = childProcess.execSync(command, {encoding: 'utf8'});
+  return output;
+}
+
+export function getPhysicalCpuCount() {
+  const platform = os.platform();
+
+  try {
+    if (platform === 'linux') {
+      const output = exec(
+        'lscpu -p | egrep -v "^#" | sort -u -t, -k 2,4 | wc -l'
+      );
+      return parseInt(output.trim(), 10);
+    }
+    if (platform === 'darwin') {
+      const output = exec('sysctl -n hw.physicalcpu_max');
+      return parseInt(output.trim(), 10);
+    }
+    if (platform === 'win32') {
+      const output = exec('WMIC CPU Get NumberOfCores');
+      return output
+        .split(os.EOL)
+        .map(parseInt)
+        .filter(value => !Number.isNaN(value))
+        .reduce((sum, number) => sum + number, 0);
+    }
+    throw new Error('Unexpected OS');
+  } catch {
+    const cores = os.cpus().filter((cpu, index) => {
+      const hasHyperthreading = cpu.model.includes('Intel');
+      const isOdd = index % 2 === 1;
+      return !hasHyperthreading || isOdd;
+    });
+    return cores.length;
+  }
+}
+
+// TODO: observe and improve this
+export function getRecommendedMaxNumberOfDevices() {
+  const logicalCpuInfos = os.cpus();
+  const cpuSpeed = logicalCpuInfos[0].speed;
+  const cpuCount = logicalCpuInfos.length;
+
+  const value = Math.max(
+    MIN_NUMBER_OF_DEVICES,
+    Math.trunc(cpuCount * (cpuSpeed / 2000))
+  );
+
+  return value;
+}
+
+export const recommendedMaxNumberOfDevices = getRecommendedMaxNumberOfDevices();