2.27. /proc/statThis file keeps track of a variety of different statistics about the system since it was lastrestarted. The contents of /proc/stat, which can be quite long, usually begins like thefollowing example:cpu 259246 7001 60190 34250993 137517 772 0 cpu0 259246 7001 60190 34250993137517 772 0 intr 354133732 347209999 2272 0 4 4 0 0 3 1 1249247 0 0 80143 0422626 5169433 ctxt 12547729 btime 1093631447 processes 130523 procs_running1 procs_blocked 0 preempt 5651840 cpu 209841 1554 21720 118519346 72939 15427168 cpu0 42536 798 4841 14790880 14778 124 3117 cpu1 24184 569 387514794524 30209 29 3130 cpu2 28616 11 2182 14818198 4020 1 3493 cpu3 35350 62942 14811519 3045 0 3659 cpu4 18209 135 2263 14820076 12465 0 3373 cpu520795 35 1866 14825701 4508 0 3615 cpu6 21607 0 2201 14827053 2325 0 3334cpu7 18544 0 1550 14831395 1589 0 3447 intr 15239682 14857833 6 0 6 6 0 5 01 0 0 0 29 0 2 0 0 0 0 0 0 0 94982 0 286812 ctxt 4209609 btime 1078711415processes 21905 procs_running 1 procs_blocked 0Some of the more commonly used statistics include:• cpu — Measures the number of jiffies (1/100 of a second for x86 systems) that the systemhas been in user mode, user mode with low priority (nice), system mode, idle task, I/O wait,IRQ (hardirq), and softirq respectively. The IRQ (hardirq) is the direct response to a hardwareevent. The IRQ takes minimal work for queuing the "heavy" work up for the softirq to execute.The softirq runs at a lower priority than the IRQ and therefore may be interrupted morefrequently. The total for all CPUs is given at the top, while each individual CPU is listed belowwith its own statistics. The following example is a 4-way Intel Pentium Xeon configuration withmulti-threading enabled, therefore showing four physical processors and four virtualprocessors totaling eight processors.• page — The number of memory pages the system has written in and out to disk.• swap — The number of swap pages the system has brought in and out.• intr — The number of interrupts the system has experienced.• btime — The boot time, measured in the number of seconds since January 1, 1970,otherwise known as the epoch.2.28. /proc/swapsThis file measures swap space and its utilization. For a system with only one swap partition, theoutput of /proc/swap may look similar to the following:Filename Type Size Used Priority /dev/mapper/VolGroup00-LogVol01 partition524280 0 -1While some of this information can be found in other files in the /proc/ directory, /proc/swapChapter 5. The proc File System64
