Update io engine comments

Some were plain wrong, mainly because they were born through
copying an existing engine.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/engines/cpu.c b/engines/cpu.c
index b6f9075d365be76fe944a33101cf6eff3b195b88..d10669df0db0f4101138f68cc1b5589e31487273 100644 (file)
--- a/engines/cpu.c
+++ b/engines/cpu.c
@@ -1,3 +1,10 @@
+/*
+ * CPU engine
+ *
+ * Doesn't transfer any data, merely burns CPU cycles according to
+ * the settings.
+ *
+ */
 #include "../fio.h"
 #include "../os.h"
 

diff --git a/engines/libaio.c b/engines/libaio.c
index 5295eadfacc113f4a3f13fd0085b205a6a6fe572..78f43ef1e721bdbb1655ceabb7e57b40768c090a 100644 (file)
--- a/engines/libaio.c
+++ b/engines/libaio.c
@@ -1,5 +1,7 @@
 /*
- * native linux aio io engine
+ * libaio engine
+ *
+ * IO engine using the Linux native aio interface.
  *
  */
 #include <stdio.h>

diff --git a/engines/mmap.c b/engines/mmap.c
index 0922e97e045d7baa3e938867bcfd5dcd8556777d..17cf5fcfc9964efa53c91877ec05fc7c3c56e6ae 100644 (file)
--- a/engines/mmap.c
+++ b/engines/mmap.c
@@ -1,5 +1,8 @@
 /*
- * regular read/write sync io engine
+ * mmap engine
+ *
+ * IO engine that reads/writes from files by doing memcpy to/from
+ * a memory mapped region of the file.
  *
  */
 #include <stdio.h>

diff --git a/engines/net.c b/engines/net.c
index cd1fda9f54372526ddf0709c31941de77675cdd5..51bc671fc3a1ba23a0e60ce91f80cc375db0990d 100644 (file)
--- a/engines/net.c
+++ b/engines/net.c
@@ -1,5 +1,8 @@
 /*
- * Transfer data over the net.
+ * net engine
+ *
+ * IO engine that reads/writes to/from sockets.
+ *
  */
 #include <stdio.h>
 #include <stdlib.h>

diff --git a/engines/null.c b/engines/null.c
index 42a780aa17fea77d0ce44d8765e810e3b7db85b9..6397ec07be5a870d6114cd7e6b01e8bf2dcf69e3 100644 (file)
--- a/engines/null.c
+++ b/engines/null.c
@@ -1,5 +1,8 @@
 /*
- * null engine - doesn't do any transfers. Used to test fio.
+ * null engine
+ *
+ * IO engine that doesn't do any real IO transfers, it just pretends to.
+ * The main purpose is to test fio itself.
  *
  */
 #include <stdio.h>

diff --git a/engines/posixaio.c b/engines/posixaio.c
index 9ee3ca6bfbe680ee4b78c5dc6350a6528e35729a..7d9aaaf18314bffe3ea30fe211918d69e89b8095 100644 (file)
--- a/engines/posixaio.c
+++ b/engines/posixaio.c
@@ -1,5 +1,7 @@
 /*
- * posix aio io engine
+ * posixaio engine
+ *
+ * IO engine that uses the posix defined aio interface.
  *
  */
 #include <stdio.h>

diff --git a/engines/sg.c b/engines/sg.c
index 98ecbd1c25a0ca52a003c85e75fe2090ee8a7433..84c2afe6c354158f6edbbf98fb12f0e0de09d55c 100644 (file)
--- a/engines/sg.c
+++ b/engines/sg.c
@@ -1,5 +1,7 @@
 /*
- * scsi generic sg v3 io engine
+ * sg engine
+ *
+ * IO engine that uses the Linux SG v3 interface to talk to SCSI devices
  *
  */
 #include <stdio.h>

diff --git a/engines/splice.c b/engines/splice.c
index c366a2ebef7fb0b6a67a0ec43dcfb2643a236283..59bf7e4f8ed19660d694a4ebf3de0718d27fe583 100644 (file)
--- a/engines/splice.c
+++ b/engines/splice.c
@@ -1,5 +1,8 @@
 /*
- * splice io engine
+ * splice engine
+ *
+ * IO engine that transfers data by doing splices to/from pipes and
+ * the files.
  *
  */
 #include <stdio.h>

diff --git a/engines/sync.c b/engines/sync.c
index b1776d210d4cb42765935238b747d047870e34ec..a137282786e8759f0c175230a2c45206a814235d 100644 (file)
--- a/engines/sync.c
+++ b/engines/sync.c
@@ -1,5 +1,8 @@
 /*
- * regular read/write sync io engine
+ * sync engine
+ *
+ * IO engine that does regular read(2)/write(2) with lseek(2) to transfer
+ * data.
  *
  */
 #include <stdio.h>

diff --git a/engines/syslet-rw.c b/engines/syslet-rw.c
index fe400daa501dd4e8e31ecc1db6129ab7fb0bc921..279884a5d041094774cb7bfcde31266fb642b2fe 100644 (file)
--- a/engines/syslet-rw.c
+++ b/engines/syslet-rw.c
@@ -1,5 +1,8 @@
 /*
- * read/write() engine that uses syslet to be async
+ * syslet engine
+ *
+ * IO engine that does regular pread(2)/pwrite(2) to transfer data, but
+ * with syslets to make the execution async.
  *
  */
 #include <stdio.h>