----- Original Message ----- > 2011/6/18 Igor Galić <i.ga...@brainsware.org>: > > > > > > ----- Original Message ----- > >> On Friday 17 June 2011, Graham Leggett wrote: > >> > We used openssl to make our non blocking event driven stuff > >> > work, > >> > and it works really well (once you've properly handled > >> > SSL_ERROR_WANT_READ and SSL_ERROR_WANT_WRITE). There is no > >> > reason > >> > I can see that would stop us using openssl to be async in httpd, > >> > we just need to refactor the mod_ssl code to actually do it. > >> > >> Someone (Paul?) once told me that openssl is not very good when it > >> comes to async access to the session cache (which could need > >> network > >> io if using memcached), CRLs (which I could imagine to reside in > >> LDAP) > >> and similar things. But this would have to be evaluated. > >> > >> > The tricky part with event driven code is the really bad support > >> > for event driven file access. We used libev as our core event > >> > loop, which does a significant amount of work to make files and > >> > sockets work the same way in the event loop as best it can in a > >> > portable way. Don't know of any other event loop that does this. > >> > It's difficult trying to do the event driven thing if you > >> > intersperse event driven socket handling with blocking file > >> > handling, you end up with many requests blocked by an unrelated > >> > system call. > >> > >> Yes, I guess we would need a pool of lightweight worker threads > >> that > >> does the file io (especially sendfile). Those threads would > >> probably > >> get by with very small stack sizes and use little resources. If > >> the > >> event library we choose already has this built in, we can of > >> course > >> use that, too. > > > > This kind of reminds me of the architecture of Apache Traffic > > Server > > see http://www.slideshare.net/zwoop/rit-2011-ats > > > > Yes, ATS is the right model I think, but I don't think the... C++isms > and general bagage that comes along with it are ideal for httpd > though?
I was merely referring to the architecture, not its implementation :) i -- Igor Galić Tel: +43 (0) 664 886 22 883 Mail: i.ga...@brainsware.org URL: http://brainsware.org/
