Wrap thread_data in thread_segment

[fio.git] / HOWTO

diff --git a/HOWTO b/HOWTO
index e0403b0803f04cb04ef7a14832dd39b3803c34d8..386fd12aa7b14b80405a4df2851b3c0f7e967fd0 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -1677,10 +1677,28 @@ Buffers and memory
        This will be ignored if :option:`pre_read` is also specified for the
        same job.
 
        This will be ignored if :option:`pre_read` is also specified for the
        same job.
 

-.. option:: sync=bool
+.. option:: sync=str
+
+       Whether, and what type, of synchronous I/O to use for writes.  The allowed
+       values are:
+
+               **none**
+                       Do not use synchronous IO, the default.
+
+               **0**
+                       Same as **none**.
+
+               **sync**
+                       Use synchronous file IO. For the majority of I/O engines,
+                       this means using O_SYNC.
+
+               **1**
+                       Same as **sync**.
+
+               **dsync**
+                       Use synchronous data IO. For the majority of I/O engines,
+                       this means using O_DSYNC.

 
 

-       Use synchronous I/O for buffered writes. For the majority of I/O engines,
-       this means using O_SYNC. Default: false.

 
 .. option:: iomem=str, mem=str
 
 
 .. option:: iomem=str, mem=str
 


@@ -1901,14 +1919,6 @@ I/O engine
                        single CPU at the desired rate. A job never finishes unless there is
                        at least one non-cpuio job.
 
                        single CPU at the desired rate. A job never finishes unless there is
                        at least one non-cpuio job.
 

-               **guasi**
-                       The GUASI I/O engine is the Generic Userspace Asynchronous Syscall
-                       Interface approach to async I/O. See
-
-                       http://www.xmailserver.org/guasi-lib.html
-
-                       for more info on GUASI.
-

                **rdma**
                        The RDMA I/O engine supports both RDMA memory semantics
                        (RDMA_WRITE/RDMA_READ) and channel semantics (Send/Recv) for the
                **rdma**
                        The RDMA I/O engine supports both RDMA memory semantics
                        (RDMA_WRITE/RDMA_READ) and channel semantics (Send/Recv) for the


@@ -2482,7 +2492,8 @@ I/O depth
        can increase latencies. The benefit is that fio can manage submission rates
        independently of the device completion rates. This avoids skewed latency
        reporting if I/O gets backed up on the device side (the coordinated omission
        can increase latencies. The benefit is that fio can manage submission rates
        independently of the device completion rates. This avoids skewed latency
        reporting if I/O gets backed up on the device side (the coordinated omission

-       problem).
+       problem). Note that this option cannot reliably be used with async IO
+       engines.

 
 
 I/O rate
 
 
 I/O rate


@@ -2861,15 +2872,10 @@ Threads, processes and job synchronization
        ``flow=8`` and another job has ``flow=-1``, then there will be a roughly 1:8
        ratio in how much one runs vs the other.
 
        ``flow=8`` and another job has ``flow=-1``, then there will be a roughly 1:8
        ratio in how much one runs vs the other.
 

-.. option:: flow_watermark=int
-
-       The maximum value that the absolute value of the flow counter is allowed to
-       reach before the job must wait for a lower value of the counter.
-

 .. option:: flow_sleep=int
 
 .. option:: flow_sleep=int
 

-       The period of time, in microseconds, to wait after the flow watermark has
-       been exceeded before retrying operations.
+       The period of time, in microseconds, to wait after the flow counter
+       has exceeded its proportion before retrying operations.

 
 .. option:: stonewall, wait_for_previous
 
 
 .. option:: stonewall, wait_for_previous