svn commit: r293439 - in head: lib/libc/sys sys/dev/ti sys/kern sys/sys usr.bin/netstat
Gleb Smirnoff
glebius at FreeBSD.org
Fri Jan 8 21:10:43 UTC 2016
On Fri, Jan 08, 2016 at 12:44:32PM -0800, NGie Cooper wrote:
N> > Log:
N> > New sendfile(2) syscall. A joint effort of NGINX and Netflix from 2013 and
N> > up to now.
N> >
N> > The new sendfile is the code that Netflix uses to send their multiple tens
N> > of gigabits of data per second. The new implementation features asynchronous
N> > I/O, when I/O operations are launched, but not awaited to be complete. An
N> > explanation of why such behavior is beneficial compared to old one is
N> > going to be too long for a commit message, so we will skip it here.
N> >
N> > Additional features of new syscall are extra flags, which provide an
N> > application more control over data sent. The SF_NOCACHE flag tells
N> > kernel that data shouldn't be cached after it was sent. The SF_READAHEAD()
N> > macro allows to specify readahead size in pages.
N> >
N> > The new syscalls is a drop in replacement. No modifications are required
N> > to applications. One can take nginx binary for stable/10 and run it
N> > successfully on head. Although SF_NODISKIO lost its original sense, as now
N> > sendfile doesn't block, and now means something completely different (tm),
N> > using the new sendfile the old way is absolutely safe.
N> >
N> > Celebrates: Netflix global launch!
N> > Sponsored by: Nginx, Inc.
N> > Sponsored by: Netflix
N> > Relnotes: yes
N>
N> Did anyone review these changes and the other changes made recently to sys/kern and sys/net* ?
1) The review requests were sent continuosly to arch@ during last 1.5 years.
https://lists.freebsd.org/pipermail/freebsd-arch/2014-May/015385.html
2) Team of engineers at Netflix has a lot of code build on top of that code,
e.g. SSL_sendfile(). Of course, writing something on top assumes reviewing,
so assume it reviewed thoroughly by rrs at . Actually, here is list of people
who did some review of the code: emax@, rrs@, scottl@, gallatin@, imp at .
3) Do you have any particulars concerns with this change or those made recently
to sys/kern and sys/net*?
--
Totus tuus, Glebius.
More information about the svn-src-head
mailing list