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[Qemu-devel] [PATCH v4 0/2] qemu-qdisk: Implementation of grant copy ope
From: |
Paulina Szubarczyk |
Subject: |
[Qemu-devel] [PATCH v4 0/2] qemu-qdisk: Implementation of grant copy operation. |
Date: |
Tue, 16 Aug 2016 08:55:54 +0200 |
Hi,
It is a proposition for implementation of grant copy operation in qemu-qdisk
and interface in libxc/libs.
Changes since v3:
Interface:
- revert to cast from xengnttab_grant_copy_segment_t
to ioctl_gntdev_grant_copy.
- added compile-time check to compare the libs
xengnttab_grant_copy_segment_t with the ioctl structure.
The patch relies on Wei patch introducing XENGNTTAB_BUILD_BUG_ON in
libs/gnttab.
qemu-qdisk:
- qemu_memalign/qemu_free is used instead function allocating
memory from xc.
- removed the get_buffer function instead there is a direct call
to qemu_memalign.
- moved ioreq_copy for write operation to ioreq_runio_qemu_aio.
- added struct xengnttab_grant_copy_segment_t and stub in
xen_common.h for version of Xen earlier then 480.
- added checking for version 480 to configure. The test repeats
all the operation that are required for version < 480 and
checks if xengnttab_grant_copy() is implemented.
Changes since v2:
Interface:
- dropped the changes in libxc/include/xenctrl_compat
- changed the MINOR version in Makefile
- replaced 'return -1' -> 'abort()'in libs/gnttab/gnttab_unimp.c
- moved the struct 'xengnttab_copy_grant_segment' to
libs/gnttab/include/xengnttab.h
- added explicit assingment to ioctl_gntdev_grant_copy_segment
to the linux part
qemu-qdisk:
- to use the xengnttab_* function directly added -lxengnttab to configure
and include <xengnttab.h> in include/hw/xen/xen_common.h
- in ioreq_copy removed an out path, changed a log level, made explicit
assignement to 'xengnttab_copy_grant_segment'
* I did not change the way of testing if grant_copy operation is implemented.
As far as I understand if the code from gnttab_unimp.c is used then the
gnttab
device is unavailable and the handler to gntdev would be invalid. But
if the handler is valid then the ioctl should return operation unimplemented
if the gntdev does not implement the operation.
Changes since v1:
Interface:
- changed the interface to call grant copy operation to match ioctl
int xengnttab_grant_copy(xengnttab_handle *xgt,
uint32_t count,
xengnttab_grant_copy_segment_t* segs)
- added a struct 'xengnttab_copy_grant_segment' definition to tools/libs
/gnttab/private.h, tools/libxc/include/xenctrl_compat.h
- changed the function 'osdep_gnttab_grant_copy' which right now just
call the ioctl
- added a new VER1.1 to tools/libs/gnttab/libxengnttab.map
qemu-qdisk:
- removed the 'ioreq_write','ioreq_read_init','ioreq_read' functions
- implemented 'ioreq_init_copy_buffers', 'ioreq_copy'
- reverted the removal of grant map and introduced conditional invoking
grant copy or grant map
- resigned from caching the local buffers on behalf of allocating the
required amount of pages at once. The cached structure would require
to have an lock guard and I suppose that the performance improvement
would degraded.
For the functional test I attached the device with a qdisk backend to the
guest,
mounted, performed some reads and writes.
I run fio tests[1] with different iodepth and size of the block. The test can
be
accessed on my github[2] but mainly after the warm up I run for 60 seconds:
fio --time_based \
--clocksource=clock_gettime \
--rw=randread \
--random_distribution=pareto:0.9 \
--size=10g \
--direct='1' \
--ioengine=libaio \
--filename=$DEV \
--iodepth=$IODEPTH \
--bs=$BS \
--name=$NAME \
--runtime=$RUNTIME >> $FILENAME
The test were repeated at least three times.
[1]
https://docs.google.com/spreadsheets/d/1E6AMiB8ceJpExL6jWpH9u2yy6DZxzhmDUyFf-eUuJ0c/edit?usp=sharing
[2] https://github.com/paulina-szubarczyk/xen-benchmark
- multitest_with_iodepth.sh
Thanks and regards,
Paulina
- Re: [Qemu-devel] [PATCH v4 2/2] qdisk - hw/block/xen_disk: grant copy implementation, (continued)
[Qemu-devel] [PATCH v4 1/2] Interface for grant copy operation in libs., Paulina Szubarczyk, 2016/08/02
[Qemu-devel] [PATCH v4 0/2] qemu-qdisk: Implementation of grant copy operation.,
Paulina Szubarczyk <=