From 3d6a6f045d24b281ff94ea71c44a637f6d8f0f9e Mon Sep 17 00:00:00 2001 From: Vincent Fu Date: Mon, 1 Oct 2018 14:42:28 -0400 Subject: [PATCH] docs: enable serialize_overlap with io_submit_mode=offload Note that it is now possible to enable overlap checking in offload submission mode and that threads are required. --- HOWTO | 9 +++++++-- fio.1 | 11 +++++++++-- 2 files changed, 16 insertions(+), 4 deletions(-) diff --git a/HOWTO b/HOWTO index a2503e9a..72ef8725 100644 --- a/HOWTO +++ b/HOWTO @@ -2339,8 +2339,13 @@ I/O depth ``serialize_overlap`` tells fio to avoid provoking this behavior by explicitly serializing in-flight I/Os that have a non-zero overlap. Note that setting this option can reduce both performance and the :option:`iodepth` achieved. - Additionally this option does not work when :option:`io_submit_mode` is set to - offload. Default: false. + + This option only applies to I/Os issued for a single job except when it is + enabled along with :option:`io_submit_mode`=offload. In offload mode, fio + will check for overlap among all I/Os submitted by offload jobs with :option:`serialize_overlap` + enabled. Threads must be used for all such jobs. + + Default: false. .. option:: io_submit_mode=str diff --git a/fio.1 b/fio.1 index bf181b34..7691b2b1 100644 --- a/fio.1 +++ b/fio.1 @@ -2070,8 +2070,15 @@ changing data and the overlapping region has a non-zero size. Setting \fBserialize_overlap\fR tells fio to avoid provoking this behavior by explicitly serializing in-flight I/Os that have a non-zero overlap. Note that setting this option can reduce both performance and the \fBiodepth\fR achieved. -Additionally this option does not work when \fBio_submit_mode\fR is set to -offload. Default: false. +.RS +.P +This option only applies to I/Os issued for a single job except when it is +enabled along with \fBio_submit_mode\fR=offload. In offload mode, fio +will check for overlap among all I/Os submitted by offload jobs with \fBserialize_overlap\fR +enabled. Threads must be used for all such jobs. +.P +Default: false. +.RE .TP .BI io_submit_mode \fR=\fPstr This option controls how fio submits the I/O to the I/O engine. The default -- 2.25.1