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| author | Stefano Garzarella | 2021-07-21 11:42:10 +0200 |
|---|---|---|
| committer | Stefan Hajnoczi | 2021-07-21 14:47:50 +0200 |
| commit | 1793ad0247cad35db1ebbc04fbea0446c30a27ca (patch) | |
| tree | 3b26eff84f99fa68fcef95a40b52a3aa48ce9f72 /qemu-options.hx | |
| parent | iothread: generalize iothread_set_param/iothread_get_param (diff) | |
| download | qemu-1793ad0247cad35db1ebbc04fbea0446c30a27ca.tar.gz qemu-1793ad0247cad35db1ebbc04fbea0446c30a27ca.tar.xz qemu-1793ad0247cad35db1ebbc04fbea0446c30a27ca.zip | |
iothread: add aio-max-batch parameter
The `aio-max-batch` parameter will be propagated to AIO engines
and it will be used to control the maximum number of queued requests.
When there are in queue a number of requests equal to `aio-max-batch`,
the engine invokes the system call to forward the requests to the kernel.
This parameter allows us to control the maximum batch size to reduce
the latency that requests might accumulate while queued in the AIO
engine queue.
If `aio-max-batch` is equal to 0 (default value), the AIO engine will
use its default maximum batch size value.
Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>
Message-id: 20210721094211.69853-3-sgarzare@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Diffstat (limited to 'qemu-options.hx')
| -rw-r--r-- | qemu-options.hx | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/qemu-options.hx b/qemu-options.hx index 0c9ddc0274..99ed5ec5f1 100644 --- a/qemu-options.hx +++ b/qemu-options.hx @@ -5301,7 +5301,7 @@ SRST CN=laptop.example.com,O=Example Home,L=London,ST=London,C=GB - ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink`` + ``-object iothread,id=id,poll-max-ns=poll-max-ns,poll-grow=poll-grow,poll-shrink=poll-shrink,aio-max-batch=aio-max-batch`` Creates a dedicated event loop thread that devices can be assigned to. This is known as an IOThread. By default device emulation happens in vCPU threads or the main event loop thread. @@ -5337,7 +5337,11 @@ SRST the polling time when the algorithm detects it is spending too long polling without encountering events. - The polling parameters can be modified at run-time using the + The ``aio-max-batch`` parameter is the maximum number of requests + in a batch for the AIO engine, 0 means that the engine will use + its default. + + The IOThread parameters can be modified at run-time using the ``qom-set`` command (where ``iothread1`` is the IOThread's ``id``): |