Red Hat Enterprise Linux 5 Administration Unleashed

Multi-Core Processors 197Duplicate this file for each user who wants to view the architecture of the packagesqueried.TIPAdd this formatting line to the .rpmmacros file for the root user as well if you oftenperform RPM queries as root.Multi-Core ProcessorsA multi-core processor is a processor that contains one or more processor cores on a singleprocessor chip, with each core having its own dedicated cache. The advantages of usingmulti-core processors include the following:. More processor cores on a single processor means a smaller physical footprint for amulti-processor machine. More processor cores can fit in a single unit.. If combined with Virtualization or a similar technology, each processor core can bededicated to a virtual machine. Just switching to dual-core processors doubles thenumber of virtual machines with a dedicated processor. Refer to Appendix B,“Creating Virtual Machines,” for details on implementing the Virtualization layer.The Linux kernel recognizes the number of physical processors, the number of processorcores on each physical processor, and the total number of processor cores. It uses eachprocessor core as it would a separate physical processor. In addition to the processorvendor, speed, and cache size, the /proc/cpuinfo virtual file shows information about theprocessor cores. To view the contents of this virtual file, use the cat /proc/cpuinfocommand.Listing 8.1 shows the output on a system with two processors, with each processor havingtwo processor cores. The processor field counts the total number of processor cores forthe entire system. In Listing 8.1, this value starts with 0 and ends with 3, for a total offour processor cores. The total number of physical processors is two, as shown by thephysical id field starting at 0 for the first processor core and ending at 1 for the lastprocessor core. The value of the cpu cores field is the total number of processor cores onthe physical processor. The core id field counts the number of processor cores for eachphysical processor.8LISTING 8.1Contents of /proc/cpuinfo for a 2-Processor, Dual-Core Systemprocessor : 0vendor_id : AuthenticAMDcpu family : 15model : 33model name : AMD Opteron(tm) Processor 860stepping : 2cpu MHz : 1607.417