vps_chatr_ceiling

vps_chatr_ceiling specifies the maximum page size (in Kbytes) that can be specified when a user process uses the chatr command to specify a page size.

Acceptable Values:

Minimum
4 Kbytes
Maximum
65536 Kbytes
Default
65536 Kbytes

Specify integer value. For more information, see Specifying Parameter Values.

Description

This parameter is provided as a means to minimize lost cycle time caused by TLB (translation look-aside buffer) misses on systems using newer PA-RISC devices such as the PA-8000 that have smaller TLBs and no hardware TLB walker.

User applications can use the chatr command to specify a page size for program text and data segments, providing some flexibility for improving overall performance, depending on system configuration and object size. The specified size is then compared to the page-size value limit defined by vps_chatr_ceiling that is defined in the kernel at system-boot time. If the the value specified is larger than vps_chatr_ceiling, vps_chatr_ceiling is used.

For more information about how these parameters are used and how they affect system operation when user applications specify page sizes, refer to the whitepaper document available as a PostScript file in /usr/share/doc/var_pages.ps.

Additional Information