----- Original Message ----- > From: "Raghavendra Gowdappa" <rgowdapp@xxxxxxxxxx> > To: "Keiviw" <keiviw@xxxxxxx> > Cc: gluster-devel@xxxxxxxxxxx > Sent: Tuesday, February 23, 2016 7:30:51 AM > Subject: Re: Readdir-ahead > > > > ----- Original Message ----- > > From: "Keiviw" <keiviw@xxxxxxx> > > To: gluster-devel@xxxxxxxxxxx > > Sent: Tuesday, February 23, 2016 6:20:28 AM > > Subject: Readdir-ahead > > > > I have two questions about the performance,readdir-ahead. > > 1. In the code,the request max_size is 131072,128K. If i change the > > max_size > > to a larger size, what will happen? > > readdir-ahead winds down readdir calls with a buffer of size "max_size". If > you increase the size, each readdir (including those "preload" requests > which are not issued by application) Correction. Only preload requests are issued with buffers of size "max_size". If readdir-ahead is bypassed (for various reasons), there is no change in size of buffer. > will be done with a bigger buffer to > fetch dentries. > > > 2. As what i have said in question 1, for a larger buffer, if the second > > readdir arrives, the denty will return from the buffer or from the server? > > Only if a preload (a readdir request not initiated by application, but > instead triggered by readdir-ahead in an attempt to pre-emptively fill the > read-ahead buffer) is in progress, a readdir from application waits for its > completion. For all other cases, readdir-ahead is bypassed. Also note that > readdir-ahead is "per-fd" based cache. So, barring cases like duping an fd > (including fork() ), one shouldn't get parallel readdir requests on a single > fd. > > > > > > > > > > > > > > > _______________________________________________ > > Gluster-devel mailing list > > Gluster-devel@xxxxxxxxxxx > > http://www.gluster.org/mailman/listinfo/gluster-devel > _______________________________________________ Gluster-devel mailing list Gluster-devel@xxxxxxxxxxx http://www.gluster.org/mailman/listinfo/gluster-devel
