What is TSC in processor?

What is TSC in processor?

The Time Stamp Counter (TSC) is a 64-bit register present on all x86 processors since the Pentium. It counts the number of CPU cycles since its reset. The instruction RDTSC returns the TSC in EDX:EAX. In x86-64 mode, RDTSC also clears the upper 32 bits of RAX and RDX.

What does RDTSC do?

The rdtsc (Read Time-Stamp Counter) instruction is used to determine how many CPU ticks took place since the processor was reset. It is commonly used as a timing defense (anti-debugging technique).

What is TSC clock source?

The TSC is the preferred clocksource between the two counters, as it is the fastest one, however it can only be used if it is stable. Currently there are 4 types of TSC present: Constant. Constant TSC means that the TSC does not change with CPU frequency changes, however it does change on C state transitions.

What is linux TSC?

This is a counter implemented in every x86 microprocessor by means of a 64-bit register called TSC the register. It counts the number of clock signals arriving on the CLK pin of the processor. The current counter value can be read by accessing the TSC register.

How does malware use Rdtsc a study on operations executed by malware with CPU cycle measurement?

Some malware programs execute a busy loop until a predetermined number of CPU cycles are consumed in an operation between RDTSC instructions. Malware can utilize such busy loops for various purposes including virtual sleeps and estimation of the CPU frequency.

What is KVM clock?

kvm-clock is a Linux clocksource like tsc and hpet. ( tsc is commonly used on physical machines.) The discussion at the URL below indicates that all clocksources act like time counters that are periodically read by interrupts.

What is QEMU guest agent?

The QEMU guest agent is a daemon that runs on the virtual machine and passes information to the host about the virtual machine, users, file systems, and secondary networks.

What is steal time in Linux?

Steal time is the percentage of time a virtual CPU waits for a real CPU while the hypervisor is servicing another virtual processor. As such, it only happens in virtualized environments like AWS, GCP, Azure, vSphere, and Xen. To see the steal time in Linux, run top on the command line and look for %st.

What is total cycle time?

Cycle Time is the amount of time a team spends actually working on producing an item, up until the product is ready for shipment. It is the time it takes to complete one task.

How do I change my CPU clock speed?

How to Turn Down CPU Speed with CPU Multiplier

  1. Turn on the computer, and press the BIOS setup key to launch BIOS.
  2. Search through the BIOS menus for the “CPU Multiplier” or “CPU Ratio” adjustment option.
  3. Select the “CPU Multiplier Clock” option, and change the value to the next lower numbered option.
  4. Save and exit BIOS.

What causes CPU steal time?

CPU steal time occurs when the processes are ready to be executed by the virtual CPU, but it’s waiting for the hypervisor to allocate a physical CPU to it. This happens because the hypervisor is servicing another VM.