Switch to epoll #5911
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Switch to epoll #5911
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We could also make the change suggested in #5910 (comment) to use proper Sets. |
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contificate
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Aug 27, 2024
mg12
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Aug 29, 2024
…quivalents Also add xapi-stdext-unix or xapi-stext-threads as needed to dune. Signed-off-by: Edwin Török <[email protected]>
Use SO_RCVTIMEO socket option instead. This will cause EAGAIN or EWOULDBLOCK to be returned according to `socket(7)`. Need to be careful about the distinction between select 0 and SO_RCVTIMEO 0. select 0 would timeout immediately, but SO_RCVTIMEO would timeout never. Signed-off-by: Steven Woods <[email protected]> Signed-off-by: Edwin Török <[email protected]>
This will also allow XAPI to better defend against XSA-413 type attacks. The default TCP connection limit is 800 (configurable), and although unauthenticated clients shouldn't be able to exhaust the number of file descriptors easily, authenticated clients still could, since handling an API request might require more file descriptors to be opened. Signed-off-by: Edwin Török <[email protected]>
Signed-off-by: Edwin Török <[email protected]>
…API and xenopsd This is somewhat of a hack, as it parses the disassembled binary of xapi and xenopsd, and might break with future compiler versions that invoke functions differently. There could also be false positives if a dependency calls Unix.select for just sleeping, i.e. with all 3 arguments as empty lists, but so far we don't have any. We still have the runtime test if that happens. If the commits are reordered this does find the 'Thread.wait_timed_read' call in 'Master_database_connection', and with the correct order of the commits it passes, offering some assurance that we don't actually call 'select' anymore, not even indirectly via one of our dependencies. Signed-off-by: Edwin Török <[email protected]>
We've enabled running the unixext tests in quicktest. They open 1024 file descriptors on startup to check for the absence of select. And although that works for unixext (it is select-free), it doesn't yet work for the rest of quicktests on master (the required changes to make it work are on the epoll branch). Temporarily disable this test and add a note to reenable it on the epoll branch. Fixes: efcb7af ("CP-50448: run the QuickCheck tests in QuickTest") Signed-off-by: Edwin Török <[email protected]>
This reverts commit 7dabd1e. It was only needed on master, and we have to revert it on the epoll branch to reenable testing. Signed-off-by: Edwin Török <[email protected]>
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One small commit on top of #5910 that switches from select to epoll ~everywhere in xapi/xenopsd.
Draft because we need to merge that PR first, then have a PR to update feature/perf from master.
Will need to be rebased on #5913 once the prerequisites for that PR get merged.