From: Vladimir Davydov <vdavydov.dev@gmail.com> To: Konstantin Osipov <kostja@tarantool.org> Cc: tarantool-patches@freelists.org Subject: Re: [PATCH 1/2] xlog: use ev_sleep instead of fiber_sleep for rate limiting Date: Mon, 4 Jun 2018 12:51:33 +0300 [thread overview] Message-ID: <20180604095133.iaxtdven3kjpuff5@esperanza> (raw) In-Reply-To: <20180601175255.GA15567@atlas> On Fri, Jun 01, 2018 at 08:52:55PM +0300, Konstantin Osipov wrote: > * Vladimir Davydov <vdavydov.dev@gmail.com> [18/05/29 18:20]: > > fiber_sleep() works only if the current thread was created with > > cord_costart(). Since vinyl worker threads don't need fibers, they > > are created with cord_start() and hence can't use fiber_sleep(). > > So to be able to limit rate of vinyl dump/compaction, we have to > > use ev_sleep() instead of fiber_sleep() in xlog. This is fine by > > other xlog writers, because they don't use fibers either, neither > > they should as xlogs are written without coio. > > > > Needed for #3220 > > Please use cord_costart() in vinyl workers instead. For this to work, we would need to yield periodically (fiber_sleep(0)) while writing a run file. This would look weird as each worker thread executes just one task. Anyway, yielding in xlog_write() may be unexpected from caller's pov, because this function is blocking (writes a file) and isn't supposed to yield. One usually hands it over to coio or a worker thread, where yielding is pointless. > > We will end up needing it for other things and it's nearly free. What things?
next prev parent reply other threads:[~2018-06-04 9:51 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-05-29 15:19 [PATCH 0/2] vinyl: allow to limit dump bandwidth Vladimir Davydov 2018-05-29 15:19 ` [PATCH 1/2] xlog: use ev_sleep instead of fiber_sleep for rate limiting Vladimir Davydov 2018-06-01 17:52 ` Konstantin Osipov 2018-06-04 9:51 ` Vladimir Davydov [this message] 2018-06-07 13:11 ` Konstantin Osipov 2018-05-29 15:19 ` [PATCH 2/2] vinyl: apply box.cfg.snap_io_rate_limit to dump/compaction Vladimir Davydov 2018-06-01 17:56 ` Konstantin Osipov 2018-06-04 9:55 ` Vladimir Davydov
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