As newer systems have more and more IRQs and CPUs available in their system, the performance of reading /proc/stat frequently is getting worse and worse.
Last year, I had proposed patch to extract out the IRQ line of /proc/stat into a new procfs file. However, this may break existing applications that depend on the presence of the IRQ line in /proc/stat. Davidlohr had proposed a new /proc/stat2 file which is almost the same as /proc/stat except that it has no IRQ line. This will require change in applications to use the new procfs file. This patchset uses a different approach to reduce the performance impact by using a sysctl parameter to control the maximum frequency at which the IRQ count computation can be done. The result is that the IRQ counts from /proc/stat may be a bit stale, but still provide the needed information. Waiman Long (2): /proc/stat: Extract irqs counting code into show_stat_irqs() /proc/stat: Add sysctl parameter to control irq counts latency Documentation/sysctl/fs.txt | 16 +++++++++ fs/proc/stat.c | 87 +++++++++++++++++++++++++++++++++++++++------ kernel/sysctl.c | 12 +++++++ 3 files changed, 105 insertions(+), 10 deletions(-) -- 1.8.3.1
