chksum: fix typos, add comments

ZFS-CI-Type: quick
Signed-off-by: Alexx Saver <[email protected]>
Co-authored-by: Adam Moss <[email protected]>

Author: lzsaver

module/zfs/zfs_chksum.c

@@ -49,6 +49,9 @@ typedef struct {
 	zio_checksum_tmpl_free_t *(free);
 } chksum_stat_t;
 
+/* a state machine for the benchmark: AT_STARTUP -> AT_BENCHMARK -> AT_DONE
+   most likely, a blocking mechanism is needed in case of multiple requests */
+
 #define	AT_STARTUP	0
 #define	AT_BENCHMARK	1
 #define	AT_DONE		2
@@ -155,11 +158,11 @@ chksum_run(chksum_stat_t *cs, abd_t *abd, void *ctx, int round,
 	switch (round) {
 	case 1: /* 1k */
 		size = 1<<10; loops = 128; break;
-	case 2: /* 2k */
+	case 2: /* 4k */
 		size = 1<<12; loops = 64; break;
-	case 3: /* 4k */
+	case 3: /* 16k */
 		size = 1<<14; loops = 32; break;
-	case 4: /* 16k */
+	case 4: /* 64k */
 		size = 1<<16; loops = 16; break;
 	case 5: /* 256k */
 		size = 1<<18; loops = 8; break;
@@ -181,6 +184,7 @@ chksum_run(chksum_stat_t *cs, abd_t *abd, void *ctx, int round,
 	} while (run_time_ns < MSEC2NSEC(1));
 	kpreempt_enable();
 
+	/* will 64 bits always be enough to store the value? */
 	run_bw = size * run_count * NANOSEC;
 	run_bw /= run_time_ns; /* B/s */
 	*result = run_bw/1024/1024; /* MiB/s */