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2022-01-12aio-posix: split poll check from ready handlerStefan Hajnoczi1-2/+2
Adaptive polling measures the execution time of the polling check plus handlers called when a polled event becomes ready. Handlers can take a significant amount of time, making it look like polling was running for a long time when in fact the event handler was running for a long time. For example, on Linux the io_submit(2) syscall invoked when a virtio-blk device's virtqueue becomes ready can take 10s of microseconds. This can exceed the default polling interval (32 microseconds) and cause adaptive polling to stop polling. By excluding the handler's execution time from the polling check we make the adaptive polling calculation more accurate. As a result, the event loop now stays in polling mode where previously it would have fallen back to file descriptor monitoring. The following data was collected with virtio-blk num-queues=2 event_idx=off using an IOThread. Before: 168k IOPS, IOThread syscalls: 9837.115 ( 0.020 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 16, iocbpp: 0x7fcb9f937db0) = 16 9837.158 ( 0.002 ms): IO iothread1/620155 write(fd: 103, buf: 0x556a2ef71b88, count: 8) = 8 9837.161 ( 0.001 ms): IO iothread1/620155 write(fd: 104, buf: 0x556a2ef71b88, count: 8) = 8 9837.163 ( 0.001 ms): IO iothread1/620155 ppoll(ufds: 0x7fcb90002800, nfds: 4, tsp: 0x7fcb9f1342d0, sigsetsize: 8) = 3 9837.164 ( 0.001 ms): IO iothread1/620155 read(fd: 107, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.174 ( 0.001 ms): IO iothread1/620155 read(fd: 105, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.176 ( 0.001 ms): IO iothread1/620155 read(fd: 106, buf: 0x7fcb9f939cc0, count: 512) = 8 9837.209 ( 0.035 ms): IO iothread1/620155 io_submit(ctx_id: 140512552468480, nr: 32, iocbpp: 0x7fca7d0cebe0) = 32 174k IOPS (+3.6%), IOThread syscalls: 9809.566 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0cdd62be0) = 32 9809.625 ( 0.001 ms): IO iothread1/623061 write(fd: 103, buf: 0x5647cfba5f58, count: 8) = 8 9809.627 ( 0.002 ms): IO iothread1/623061 write(fd: 104, buf: 0x5647cfba5f58, count: 8) = 8 9809.663 ( 0.036 ms): IO iothread1/623061 io_submit(ctx_id: 140539805028352, nr: 32, iocbpp: 0x7fd0d0388b50) = 32 Notice that ppoll(2) and eventfd read(2) syscalls are eliminated because the IOThread stays in polling mode instead of falling back to file descriptor monitoring. As usual, polling is not implemented on Windows so this patch ignores the new io_poll_read() callback in aio-win32.c. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Message-id: 20211207132336.36627-2-stefanha@redhat.com [Fixed up aio_set_event_notifier() calls in tests/unit/test-fdmon-epoll.c added after this series was queued. --Stefan] Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2019-06-12Include qemu/module.h where needed, drop it from qemu-common.hMarkus Armbruster1-2/+1
Signed-off-by: Markus Armbruster <armbru@redhat.com> Message-Id: <20190523143508.25387-4-armbru@redhat.com> [Rebased with conflicts resolved automatically, except for hw/usb/dev-hub.c hw/misc/exynos4210_rng.c hw/misc/bcm2835_rng.c hw/misc/aspeed_scu.c hw/display/virtio-vga.c hw/arm/stm32f205_soc.c; ui/cocoa.m fixed up]
2018-05-15file-win32: Switch to byte-based callbacksEric Blake1-3/+2
We are gradually moving away from sector-based interfaces, towards byte-based. Make the change for the last few sector-based callbacks in the file-win32 driver. Note that the driver was already using byte-based calls for performing actual I/O, so this just gets rid of a round trip of scaling; however, as I don't know if Windows is tolerant of non-sector AIO operations, I went with the conservative approach of modifying .bdrv_refresh_limits to override the block layer defaults back to the pre-patch value of 512. Signed-off-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2017-02-21block: explicitly acquire aiocontext in aio callbacks that need itPaolo Bonzini1-3/+0
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170213135235.12274-16-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-02-21block: explicitly acquire aiocontext in callbacks that need itPaolo Bonzini1-4/+6
This covers both file descriptor callbacks and polling callbacks, since they execute related code. Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Reviewed-by: Fam Zheng <famz@redhat.com> Reviewed-by: Daniel P. Berrange <berrange@redhat.com> Message-id: 20170213135235.12274-14-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2017-01-03aio: add AioPollFn and io_poll() interfaceStefan Hajnoczi1-2/+2
The new AioPollFn io_poll() argument to aio_set_fd_handler() and aio_set_event_handler() is used in the next patch. Keep this code change separate due to the number of files it touches. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 20161201192652.9509-3-stefanha@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-07-18linux-aio: share one LinuxAioState within an AioContextPaolo Bonzini1-1/+1
This has better performance because it executes fewer system calls and does not use a bottom half per disk. Originally proposed by Ming Lei. [Changed #include "raw-aio.h" to "block/raw-aio.h" in win32-aio.c to fix build error as reported by Peter Maydell <peter.maydell@linaro.org>. --Stefan] Acked-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Message-id: 1467650000-51385-1-git-send-email-pbonzini@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> squash! linux-aio: share one LinuxAioState within an AioContext
2016-01-20block: Clean up includesPeter Maydell1-0/+1
Clean up includes so that osdep.h is included first and headers which it implies are not included manually. This commit was created with scripts/clean-includes. Signed-off-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2015-10-23aio: Add "is_external" flag for event handlersFam Zheng1-2/+3
All callers pass in false, and the real external ones will switch to true in coming patches. Signed-off-by: Fam Zheng <famz@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20block: Rename BlockDriverCompletionFunc to BlockCompletionFuncMarkus Armbruster1-1/+1
I'll use it with block backends shortly, and the name is going to fit badly there. It's a block layer thing anyway, not just a block driver thing. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-10-20block: Rename BlockDriverAIOCB* to BlockAIOCB*Markus Armbruster1-2/+2
I'll use BlockDriverAIOCB with block backends shortly, and the name is going to fit badly there. It's a block layer thing anyway, not just a block driver thing. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2014-09-22block: Rename qemu_aio_release -> qemu_aio_unrefFam Zheng1-2/+2
Suggested-by: Benoît Canet <benoit.canet@irqsave.net> Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-09-22win32-aio: Drop win32_aiocb_info.cancelFam Zheng1-14/+0
Signed-off-by: Fam Zheng <famz@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-08-15raw-win32: Handle failure for potentially large allocationsKevin Wolf1-1/+5
Some code in the block layer makes potentially huge allocations. Failure is not completely unexpected there, so avoid aborting qemu and handle out-of-memory situations gracefully. This patch addresses the allocations in the raw-win32 block driver. Signed-off-by: Kevin Wolf <kwolf@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-04block/raw-win32: implement .bdrv_detach/attach_aio_context()Stefan Hajnoczi1-4/+17
Drop the assumption that we're using the main AioContext for raw-win32. Convert the aio-win32 code to support detach/attach and replace qemu_aio_wait() with aio_poll(). The .bdrv_detach/attach_aio_context() interfaces move the aio-win32 event notifier from the old to the new AioContext. Cc: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2014-06-04block/raw-win32: create one QEMUWin32AIOState per BDRVRawStateStefan Hajnoczi1-0/+8
Each QEMUWin32AIOState event notifier is associated with an AioContext. Since BlockDriverState instances can use different AioContexts we cannot continue to use a global QEMUWin32AIOState. Let each BDRVRawState have its own QEMUWin32AIOState and free it when BDRVRawState is closed. Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-08-22win32-aio: drop win32_aio_flush_cb()Stefan Hajnoczi1-9/+1
The io_flush argument to qemu_aio_set_event_notifier() has been removed since the block layer learnt to drain requests by itself. Fix the Windows build for win32-aio.o by updating the qemu_aio_set_event_notifier() call and dropping win32_aio_flush_cb(). Reviewed-by: Stefan Weil <sw@weilnetz.de> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-05-18Remove twice include of qemu-common.hQiao Nuohan1-1/+0
This patch is used to remove twice include of "qemu-common.h" in block/win32-aio.c Signed-off-by: Qiao Nuohan <qiaonuohan@cn.fujitsu.com> Reviewed-by: Stefan Weil <sw@weilnetz.de> Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
2013-01-18win32-aio: use iov utility functions instead of open-coding themMichael Tokarev1-14/+3
We have iov_from_buf() and iov_to_buf(), use them instead of open-coding these in block/win32-aio.c Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-01-17win32-aio: Fix memory leakKevin Wolf1-1/+1
The buffer is allocated for both reads and writes, and obviously it should be freed even if an error occurs. Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-01-17win32-aio: Fix vectored readsKevin Wolf1-1/+1
Copying data in the right direction really helps a lot! Cc: qemu-stable@nongnu.org Signed-off-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2013-01-15win32-aio: Fix how win32_aio_process_completion() frees bufferMarkus Armbruster1-1/+1
win32_aio_submit() allocates it with qemu_blockalign(), therefore it must be freed with qemu_vfree(), not g_free(). Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
2012-12-19misc: move include files to include/qemu/Paolo Bonzini1-3/+3
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-12-19block: move include files to include/block/Paolo Bonzini1-2/+2
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2012-11-14aio: rename AIOPool to AIOCBInfoStefan Hajnoczi1-2/+2
Now that AIOPool no longer keeps a freelist, it isn't really a "pool" anymore. Rename it to AIOCBInfo and make it const since it no longer needs to be modified. Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-11-14block: Workaround for older versions of MinGW gccStefan Weil1-5/+5
Versions before gcc-4.6 don't support unnamed fields in initializers (see http://gcc.gnu.org/bugzilla/show_bug.cgi?id=10676). Offset and OffsetHigh belong to an unnamed struct which is part of an unnamed union. Therefore the original code does not work with older versions of gcc. Signed-off-by: Stefan Weil <sw@weilnetz.de> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
2012-10-31raw-win32: implement native asynchronous I/OPaolo Bonzini1-0/+226
With the new support for EventNotifiers in the AIO event loop, we can hook a completion port to every opened file and use asynchronous I/O on them. Wine's support is extremely inefficient, also because it really does the I/O synchronously on regular files. (!) But it works, and it is good to keep the Win32 and POSIX ports as similar as possible. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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