Those of you that don’t like being in the dark about the performance of your devices and tech gadgets probably spend a lot of time monitoring the performance of all your devices. iOS is for the most part managed automatically and doesn't give the user a whole lot of information about its performance information; however, with a new jailbreak tweak called Ultra iMeter by iOS developer wesley6j, you can keep an eye on the real-time system information of your iOS device and keep an eye on its performance.
The tweak harnesses the power of Activator to let you invoke a Status Bar system meter on demand. Invoking the Activator action you choose when the meter is hidden will show it, and invoking the Activator action you choose when the meter is showing will hide it. The meter is shown in the screenshot above, and offers a ton of information about the current performance of your iOS device by showing you what's going in real time.
The information that the meter shows you, based on the screenshot above, goes in this order: [26%] is the current CPU usage, [153M] is the current amount of free memory, [11G] is the current amount of free storage, [00:37] is the current time in 24-hour format, [W] is the network type (Wi-Fi in this case), [0.04K] is the current network speed, [207M] is the amount of data that has been transferred over the network,  is a warning icon (happy face is good).
The first option you will find is the ability to set an Activator action for toggling the meter in the Status Bar. Under that, you will find settings for configuring your Wi-Fi and Data allowances, which will directly impact when you get a warning icon for your data. This is good for when you have a limited amount of data per month with your carrier and you want to know when you’re getting close to your limit.
Below that, you will find a place to configure when you want to receive a warning icon for low disk storage, when you want to receive a warning icon for low memory, when you want to receive a warning icon for high CPU usage, and configure how your network speed and RAM appear, as well as choose an update interval for the real-time information to be updated before your eyes.
Coming up in a future update are options for theming to make it look better. For now, the look of the tweak is pretty bare-bones, but it gets done what it needs to get done. If you would like to give the tweak a try, you will find it in Cydia's BigBoss repository for $1.99. You will need to have Activator installed to use the tweak.