README: how to compile fio on Windows 64 bits

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index 8073240ef14074b5007bafa4296b913f1951f647..ea8730caea033ec4fce10d00ceef7256170bfd8e 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -1402,6 +1402,9 @@ that defines them is selected.
 [netsplice] port=int
 [net] port=int The TCP or UDP port to bind to or connect to.
 
+[netsplice] nodelay=bool
+[net] nodelay=bool     Set TCP_NODELAY on TCP connections.
+
 [netsplice] protocol=str
 [netsplice] proto=str
 [net] protocol=str
@@ -1693,3 +1696,18 @@ write      Write 'length' bytes beginning from 'offset'
 sync       fsync() the file
 datasync   fdatasync() the file
 trim       trim the given file from the given 'offset' for 'length' bytes
+
+
+9.0 CPU idleness profiling
+
+In some cases, we want to understand CPU overhead in a test. For example,
+we test patches for the specific goodness of whether they reduce CPU usage.
+fio implements a balloon approach to create a thread per CPU that runs at
+idle priority, meaning that it only runs when nobody else needs the cpu.
+By measuring the amount of work completed by the thread, idleness of each
+CPU can be derived accordingly.
+
+An unit work is defined as touching a full page of unsigned characters. Mean
+and standard deviation of time to complete an unit work is reported in "unit
+work" section. Options can be chosen to report detailed percpu idleness or
+overall system idleness by aggregating percpu stats.