Collect a block-wise histogram of trim and write errors

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 3f258db8cf94178da849d75d4a8fb4c028e5367f..6c7abcc7979d275a0bea276fd09deae69a587fec 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -1468,6 +1468,11 @@ log_store_compressed=bool        If set, and log_compression is also set,
                command line parameter. The files will be stored with a
                .fz suffix.
 
+block_error_percentiles=bool   If set, record errors in trim block-sized
+               units from writes and trims and output a histogram of
+               how many trims it took to get to errors, and what kind
+               of error was encountered.
+
 lockmem=int    Pin down the specified amount of memory with mlock(2). Can
                potentially be used instead of removing memory or booting
                with less memory to simulate a smaller amount of memory.
@@ -1507,13 +1512,13 @@ clat_percentiles=bool Enable the reporting of percentiles of
                 completion latencies.
 
 percentile_list=float_list Overwrite the default list of percentiles
-               for completion latencies. Each number is a floating
-               number in the range (0,100], and the maximum length of
-               the list is 20. Use ':' to separate the numbers, and
-               list the numbers in ascending order. For example,
-               --percentile_list=99.5:99.9 will cause fio to report
-               the values of completion latency below which 99.5% and
-               99.9% of the observed latencies fell, respectively.
+               for completion latencies and the block error histogram.
+               Each number is a floating number in the range (0,100],
+               and the maximum length of the list is 20. Use ':'
+               to separate the numbers, and list the numbers in ascending
+               order. For example, --percentile_list=99.5:99.9 will cause
+               fio to report the values of completion latency below which
+               99.5% and 99.9% of the observed latencies fell, respectively.
 
 clocksource=str        Use the given clocksource as the base of timing. The
                supported options are: