Monitoring Performance in Real Time (part 2) - Using Resource Monitor

2. Using Resource Monitor

Like the Performance tab in Windows Task Manager, Resource Monitor gives you both instantaneous and recent-history readouts of key performance metrics. Also like Windows Task Manager, Resource Monitor can show you, in excruciating detail, what each process is doing.The version of Resource Monitor in Windows 7 is extremely usable and packed with enough information to keep you busy for hours or days.

To open Resource Monitor, click its shortcut on the All Programs menu (under Accessories, System Tools). Or just type resource in the Start menu search box and click the shortcut that appears at the top of the list. (In either case, you'll need administrative credentials.) Or take the direct route: type perfmon /res at a command prompt.

Note:

You can open Resource Monitor by clicking the button at the bottom of the Performance tab in Task Manager. This is, in our opinion, the preferred way to use this utility. Start with a quick overview from Task Manager, and if you need more information call on Resource Monitor.

When you first open Resource Monitor, you see the Overview tab shown in Figure 2, which provides both detailed tables and charts that summarize performance in four areas.

Tabs along the top of the Resource Monitor window allow you to switch to a different context and focus on a specific type of resource usage. The basic layout of each tab is similar and consists of a handful of common elements.

One or more tables contain details about the resource featured on that tab. The first table on each tab is called the key table; it contains a list of all processes currently using the selected resource, with a check mark to the left of each process allowing you to filter the data displayed in additional tables on the tab. The key table at the top of the Overview tab lists all running processes, in a display that is similar to the Processes tab of Task Manager.

Within each table, you can add or hide columns, change the order of columns, and resize columns. To see the full list of available columns for an individual table, right-click the column headings for that table and choose Select Columns. On the CPU tab, for example, you can add the following normally hidden columns to the Processes table: User Name, to help identify the owner of a process; Operating System Context, to identify the Windows version a program was originally written for; Platform, to distinguish 32-bit and 64-bit processes on a 64-bit Windows installation; and Elevated, which identifies processes running with full administrative privileges. You can sort any column by clicking the heading; click again to reverse the sort order.

The heading atop each table serves several purposes. At its most basic, it contains a label that identifies the table's contents. You can also click the arrow at the right side of the heading to expand or collapse its contents. To the right of the label is one or more elements that summarize the information in that table. In Figure 3, for instance, the header above the Processes table shows the percentage of physical memory in use, while the informational graphics in the Physical Memory header show the amount of RAM in use and available.

For each of four resources—CPU, disk, network, and memory—the Overview tab presents instantaneous and recent-history graphs of two metrics. The recent-history data appears in the chart pane on the right. The instantaneous readouts are in the small squares to the right of the label in the header above each table. Each graph uses colors—green and blue—to distinguish its two data sets. The performance metrics are shown in Table 1.

For most (but not all) of the graphs in the chart pane, you'll see two lines—one blue and one green. The color keys correspond to the information on the header for the associated table. Thus, on the Overview tab, the green line on the CPU graph shows total CPU usage in real time, while the blue line shows the maximum frequency at which the CPU is operating. If you find the graphs distracting, you can hide them by clicking the right-facing arrow in the header above the graphs; you can also use the choices on the Views menu to switch to Large, Medium, and Small displays of the real-time data. The display shown here is the Small variant of the chart pane on the CPU tab.

The four charts on this tab are worth a closer look. At the top is a chart showing total CPU usage. At the bottom are two charts, one for each of the cores in this dual-core processor. The second chart, Service CPU Usage, helps identify how much of the CPU is being used by background services. If this chart shows steady, significant activity, you should take a closer look at running processes to see if any are using more than their fair share of the CPU.

For each graph, the line on the horizontal axis (the time scale) represents 5 seconds; with 11 lines, that means the display encompasses 55 seconds, not 60 seconds as the legend incorrectly notes. The vertical axis contains 10 lines and always depicts a percentage of the current scale.

In Figure 4, we see the four graphs from the Overview tab on a desktop PC that is using the Balanced power scheme. The CPU is currently running at 75 percent of its clock speed but has spent the last 45 seconds or so running at 80–95% of its full rated speed. The hard disks have seen brief spikes of activity in this time slice, loading code as new programs launched and then quieting down. Very little is happening on the network at the current time; about 30 seconds earlier, there was a brief burst of activity from the network that used only a small fraction of the gigabit speeds available. At this instant, the system is experiencing virtually no hard faults, at the rate of 1 per second (having peaked at roughly 100 a short time ago), and is using 43 percent of its physical memory.

You can stop data collection at any time and freeze the display of information completely, a useful feature if you've just observed a spike in activity and then watched it calm down, and now you want to examine the details. Click Monitor, and then click Stop Monitoring to pause the display. Click Start Monitoring on the same menu to resume the data collection and display.

Filtering the display of data in Resource Monitor is an especially valuable technique when you're trying to track down the cause of a particular burst of activity (and possibly an associated slowdown). You can also use this technique to identify services, handles, and modules associated with a particular process. On the CPU tab, for instance, you might notice that an instance of Svchost.exe is using a disproportionate amount of the CPU and doesn't seem to be showing signs of stopping. To find out why, select the check box to the left of its entry in the Processes table. The entry immediately moves to the top of the list, and the tables below pick up an orange header indicating they're filtered by the selected item. A similar orange line appears on the graph to the right to help you isolate resource usage for the filtered items.