summaryrefslogtreecommitdiffstats
path: root/include/qemu/ratelimit.h
Commit message (Collapse)AuthorAgeFilesLines
* include: Make headers more self-containedMarkus Armbruster2019-08-161-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Back in 2016, we discussed[1] rules for headers, and these were generally liked: 1. Have a carefully curated header that's included everywhere first. We got that already thanks to Peter: osdep.h. 2. Headers should normally include everything they need beyond osdep.h. If exceptions are needed for some reason, they must be documented in the header. If all that's needed from a header is typedefs, put those into qemu/typedefs.h instead of including the header. 3. Cyclic inclusion is forbidden. This patch gets include/ closer to obeying 2. It's actually extracted from my "[RFC] Baby steps towards saner headers" series[2], which demonstrates a possible path towards checking 2 automatically. It passes the RFC test there. [1] Message-ID: <87h9g8j57d.fsf@blackfin.pond.sub.org> https://lists.nongnu.org/archive/html/qemu-devel/2016-03/msg03345.html [2] Message-Id: <20190711122827.18970-1-armbru@redhat.com> https://lists.nongnu.org/archive/html/qemu-devel/2019-07/msg02715.html Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Alistair Francis <alistair.francis@wdc.com> Message-Id: <20190812052359.30071-2-armbru@redhat.com> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
* ratelimit: don't align wait time with slicesWolfgang Bumiller2018-02-151-6/+5Star
| | | | | | | | | | | It is possible for rate limited writes to keep overshooting a slice's quota by a tiny amount causing the slice-aligned waiting period to effectively halve the rate. Signed-off-by: Wolfgang Bumiller <w.bumiller@proxmox.com> Reviewed-by: Alberto Garcia <berto@igalia.com> Message-id: 20180207071758.6818-1-w.bumiller@proxmox.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* blockjob: Track job ratelimits via bytes, not sectorsEric Blake2017-07-101-1/+2
| | | | | | | | | | | | | | | | | | | | The user interface specifies job rate limits in bytes/second. It's pointless to have our internal representation track things in sectors/second, particularly since we want to move away from sector-based interfaces. Fix up a doc typo found while verifying that the ratelimit code handles the scaling difference. Repetition of expressions like 'n * BDRV_SECTOR_SIZE' will be cleaned up later when functions are converted to iterate over images by bytes rather than by sectors. Signed-off-by: Eric Blake <eblake@redhat.com> Reviewed-by: John Snow <jsnow@redhat.com> Reviewed-by: Jeff Cody <jcody@redhat.com> Reviewed-by: Kevin Wolf <kwolf@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* Improve block job rate limiting for small bandwidth valuesSascha Silbe2016-07-131-9/+34
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | ratelimit_calculate_delay() previously reset the accounting every time slice, no matter how much data had been processed before. This had (at least) two consequences: 1. The minimum speed is rather large, e.g. 5 MiB/s for commit and stream. Not sure if there are real-world use cases where this would be a problem. Mirroring and backup over a slow link (e.g. DSL) would come to mind, though. 2. Tests for block job operations (e.g. cancel) were rather racy All block jobs currently use a time slice of 100ms. That's a reasonable value to get smooth output during regular operation. However this also meant that the state of block jobs changed every 100ms, no matter how low the configured limit was. On busy hosts, qemu often transferred additional chunks until the test case had a chance to cancel the job. Fix the block job rate limit code to delay for more than one time slice to address the above issues. To make it easier to handle oversized chunks we switch the semantics from returning a delay _before_ the current request to a delay _after_ the current request. If necessary, this delay consists of multiple time slice units. Since the mirror job sends multiple chunks in one go even if the rate limit was exceeded in between, we need to keep track of the start of the current time slice so we can correctly re-compute the delay for the updated amount of data. The minimum bandwidth now is 1 data unit per time slice. The block jobs are currently passing the amount of data transferred in sectors and using 100ms time slices, so this translates to 5120 bytes/second. With chunk sizes usually being O(512KiB), tests have plenty of time (O(100s)) to operate on block jobs. The chance of a race condition now is fairly remote, except possibly on insanely loaded systems. Signed-off-by: Sascha Silbe <silbe@linux.vnet.ibm.com> Message-id: 1467127721-9564-2-git-send-email-silbe@linux.vnet.ibm.com Reviewed-by: Max Reitz <mreitz@redhat.com> Signed-off-by: Max Reitz <mreitz@redhat.com>
* Clean up decorations and whitespace around header guardsMarkus Armbruster2016-07-121-1/+1
| | | | | | | Cleaned up with scripts/clean-header-guards.pl. Signed-off-by: Markus Armbruster <armbru@redhat.com> Reviewed-by: Richard Henderson <rth@twiddle.net>
* aio / timers: Switch entire codebase to the new timer APIAlex Bligh2013-08-221-1/+1
| | | | | | | | | | | This is an autogenerated patch using scripts/switch-timer-api. Switch the entire code base to using the new timer API. Note this patch may introduce some line length issues. Signed-off-by: Alex Bligh <alex@alex.org.uk> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
* stream: fix ratelimit_set_speedDietmar Maurer2012-11-301-1/+1
| | | | | | | | The formula to compute slice_quota was wrong since commit 6ef228fc. Signed-off-by: Dietmar Maurer <dietmar@proxmox.com> Reviewed-by: Eric Blake <eblake@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
* stream: move rate limiting to a separate header filePaolo Bonzini2012-06-151-0/+48
Make the code reusable. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>