Avanti's built-in Auto-Idle feature provides an available guest-idle alternative under OpenVMS and Tru64 UNIX without installing a guest driver. It is disabled by default. See Virtual Alpha Base Settings for details.
The remainder of this topic is retained for systems that already contain third-party Charon or HP Idle software. Avanti does not distribute these utilities, and no particular utility version has been independently qualified for Avanti 5.1.0. Consult the utility supplier's current documentation and validate the intended workload before retaining or changing it.
Alpha CPU's were designed to run at 100% all the time. They do not have a reduced power mode like more modern Integrity and X86 processors. The exception is the processor used in the Tadpole, a laptop version of the Alpha. A hook was added to the firmware to signal the processor when VMS was not busy and temporarily pause the CPU by putting it into a low power state.
Historical documentation attributes the Idle Loop to SRI (now Stromasys) and later calls it the Idle Powersaver Driver. The linked third-party documentation, which may change independently of Avanti, describes its own workload restrictions:
https://stromasys.atlassian.net/wiki/spaces/DocCHAXPSMAv2240W/pages/34603068/Idle+Powersaver+Driver
Historical field reports found that the third-party driver could reduce performance for applications with high I/O throughput and low CPU use. This is not a current cross-version benchmark. If such a system shows a material regression, test without the driver or use Avanti Auto-Idle instead. The historical removal command, issued from the OpenVMS SYSTEM account and followed by the restart required by the utility's documentation, is:
$ PRODUCT REMOVE IDLE
Earlier field guidance also used the OpenVMS LOAD_SYS_IMAGES parameter to suppress SYS$IDLE at boot. Parameter meanings and defaults can vary by guest version; do not change this system-wide bit solely from this historical note. See Removing Charon and HP Idle Utilities (OpenVMS Only) for the retained removal procedure.
