On 8/21/24 5:29 AM, MANISH PANDEY wrote:
How about introducing a new rq_affinity ( may be rq_affinity = 3) for
using cpus_equal_capacity() using new flag QUEUE_FLAG_SAME_CAPACITY.
if (cpu == rq->mq_ctx->cpu ||
(!test_bit(QUEUE_FLAG_SAME_FORCE, &rq->q->queue_flags) &&
cpus_share_cache(cpu, rq->mq_ctx->cpu) &&
+ (test_bit(QUEUE_FLAG_CPU_CAPACITY, &rq->q->queue_flags))
&& cpus_equal_capacity(cpu, rq->mq_ctx->cpu)))
return false;
Could you please consider raising similar change, if this seems fine for
all.
I'm not sure that a change like the above would be acceptable.
What is the performance impact of the above change? Redirecting
completion interrupts from a slow core to a fast core causes additional
cache misses if the I/O was submitted from a slow core. Are there
perhaps use cases for which the above change slows down I/O?
Thanks,
Bart.
