[tarantool-patches] [PATCH v3 09/14] wal: a dedicated wal scheduling fiber

[Vladimir Davydov]

On Thu, Jun 13, 2019 at 10:36:30PM +0300, Георгий Кириченко wrote:
> On Thursday, June 13, 2019 5:24:52 PM MSK Vladimir Davydov wrote:
> > On Sun, Jun 09, 2019 at 11:44:38PM +0300, Georgy Kirichenko wrote:
> 
> > 
> > This adds an extra ctxsw to the relatively hot WAL writer wakeup path so
> > we can't commit it. I assume it's a temporary hack you added so that you
> > can submit this patches for review.
> This adds at most only one ctxsw on each wal branch and we could ask Alexander 
> to bench it.
> > 
> > I understand why you're doing this, but the right way would be removing
> > yields from on_commit triggers. We need to make vy_log_write yield-free.
> I'm totally agreed, however, I'm not sure could disable yields for on_commit/
> on_rollback right now.

I'll try to do that without introducing a separate vylog thread then so
as not to trigger Kostja. If I fail, we will have no choice but fall
back on a separate fiber for WAL wakeups.