Since there are irq number allocation holes, we can jump over those
holes in order to speed up show_interrupts().
In addition, the percpu kstat_irqs access logic can be refined.
System Configuration
====================
* 2-socket server with 488 cores (HT-enabled).
* The last allocated irq is 508.
* nr_irqs = 8360. The following is from dmesg.
NR_IRQS: 524544, nr_irqs: 8360, preallocated irqs: 16
The biggest hole: 7852 iterations (8360 - 509 + 1) are not necessary.
Test Result
===========
* The following result is the average execution time of ten-time
measurements about `time cat /proc/interrupts`.
no patch (ms) patched (ms) saved
------------- ------------ -------
52.4 47.3 9.7%
Adrian Huang (2):
genirq/proc: Try to jump over the unallocated irq hole whenever
possible
genirq/proc: Refine percpu kstat_irqs access logic
fs/proc/interrupts.c | 6 ++++++
kernel/irq/proc.c | 26 ++++++++++++++++++--------
2 files changed, 24 insertions(+), 8 deletions(-)
--
2.25.1
