cam/iosched: Document latency buckets correctly.

Document how latency buckets are actually computed: They are a doubling
from 20us to 10.485s by default, but based at
kern.cam.iosched.bucket_base_us and increase with a ratio of
kern.cam.iosched.bucket_ration / 100 from one to the next.

Sponsored by:		Netflix

This commit is contained in:

Warner Losh

2024-05-02 15:58:55 -06:00

parent b25ceb97ed

commit d21c19d412

1 changed files with 6 additions and 1 deletions

									
										sys/cam/cam_iosched.c
									
		+6
		-1
	
												View File
												
				@@ -1070,7 +1070,12 @@ cam_iosched_iop_stats_sysctl_init(struct cam_iosched_softc *isc, struct iop_stat

					    CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE,

					    &ios->latencies, 0,

					    cam_iosched_sysctl_latencies, "A",

					    "Array of power of 2 latency from 1ms to 1.024s");

					    "Array of latencies, a geometric progresson from\n"

					    "kern.cam.iosched.bucket_base_us with a ratio of\n"

					    "kern.cam.iosched.bucket_ration / 100 from one to\n"

					    "the next. By default 20 steps from 20us to 10.485s\n"

					    "by doubling.");

				}

				static void