Unsourced material may be challenged and removed. Since HPET compares the actual timer value and the programmed target value on equality rather than “greater or equal”, interrupts can be missed if the target time has already passed when the comparator value is written into the chip’s register. This causes an interrupt at every millisecond even if the application needs to do actual work less frequently. So basically you are saying that I should have it enabled because it doesn’t do neither good nor bad? Will the computer have better entropy with HPET? Retrieved from ” https:
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Email Required, but never shown. It can also be a nuisance that the ever-increasing processor speeds of newer processor designs make this usable time span shorter still. Unsourced material may be challenged and removed. February Learn how and when to remove this template message. Will the computer have better entropy with HPET? Performance is not a problem, I would like a good lniux, and cryptographically secure random numbers.
Is it better to enable HPET or leave it disabled. Retrieved from ” https: So basically you are saying that I should have it enabled because it doesn’t do neither good nor bad? Sign up using Facebook. HPET is meant to supplement and replace the programmable interval timer ljnux the RTC’s periodic interrupt function.
HPET is a continuously running timer that counts upward, not a one-shot device that counts down to zero, causes one interrupt and then stops. Comparators can be driven by the operating system, e. Each comparator can generate an interrupt when the least significant bits are equal to the corresponding bits of the bit main counter value.
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Compared to these older timer circuits, the HPET has higher frequency and wider bit counters although they can be driven in hpeh mode. Only on certain embedded processor architectures such as ARC will you have problems involving the lack of a high-resolution TSC instruction. Formerly referred to by Intel as a Multimedia Timer the term HPET was selected to avoid confusion with the multimedia timers as a software feature introduced in the MultiMedia Extensions to Windows 3.
INI file to enforce its use.
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While and RTC can be put into an HPET-like one-shot mode, the set-up process is so slow that their one-shot mode is not used in practice for tasks requiring precise scheduling.
I have and older non-embedded AMD processor. Home Questions Tags Users Unanswered. Besides mentioning the race condition discussed above, a VMware document also lists some other drawbacks: This causes an interrupt at every millisecond even if the application needs to do actual work less frequently. Webarchive template archiveis links Articles needing additional references from February All articles needing additional references Articles to be expanded from February All articles to be expanded Articles using small message boxes All articles with unsourced statements Articles with unsourced statements from December This section needs expansion with: This has the express advantage of being independent of the CPU frequency and still provides a very reasonable sub-microsecond resolution and accuracy.
So the HPET is only there to satisfy the system’s high speed needs. These comparators are or bit-wide.
Some hardware has both.
This page was last edited on 24 Septemberat A gpet in that environment for 10 million event counts found that TSC took about 0.