On 10/10/2016 11:28, Slawa Olhovchenkov wrote: > On Mon, Oct 10, 2016 at 10:46:27AM -0700, John Baldwin wrote: > >> On Monday, October 10, 2016 02:09:01 PM Slawa Olhovchenkov wrote: >>> On Mon, Oct 03, 2016 at 11:15:44PM +0000, John Baldwin wrote: >>> >>>> Author: jhb >>>> Date: Mon Oct 3 23:15:44 2016 >>>> New Revision: 306661 >>>> URL: https://svnweb.freebsd.org/changeset/base/306661 >>>> >>>> Log: >>>> MFC 303405: Add support for zero-copy aio_write() on TOE sockets. >>>> >>>> AIO write requests for a TOE socket on a Chelsio T4+ adapter can now >>>> DMA directly from the user-supplied buffer. This is implemented by >>>> wiring the pages backing the user-supplied buffer and queueing special >>>> mbufs backed by raw VM pages to the socket buffer. The TOE code >>>> recognizes these special mbufs and builds a sglist from the VM page >>>> array associated with the mbuf when queueing a work request to the TOE. >>>> >>>> Because these mbufs do not have an associated virtual address, m_data >>>> is not valid. Thus, the AIO handler does not invoke sosend() directly >>>> for these mbufs but instead inlines portions of sosend_generic() and >>>> tcp_usr_send(). >>>> >>>> An aiotx_buffer structure is used to describe the user buffer (e.g. >>>> it holds the array of VM pages and a reference to the AIO job). The >>>> special mbufs reference this structure via m_ext. Note that a single >>>> job might be split across multiple mbufs (e.g. if it is larger than >>>> the socket buffer size). The 'ext_arg2' member of each mbuf gives an >>>> offset relative to the backing aiotx_buffer. The AIO job associated >>>> with an aiotx_buffer structure is completed when the last reference to >>>> the structure is released. >>>> >>>> Zero-copy aio_write()'s for connections associated with a given >>>> adapter can be enabled/disabled at runtime via the >>>> 'dev.t[45]nex.N.toe.tx_zcopy' sysctl. >>>> >>>> Sponsored by: Chelsio Communications >>> >>> Do you have any public available application patches for support this? >>> May be nginx? >> >> Applications need to use aio_read(), ideally with at least 2 buffers (so >> queue two reads, then when a read completes, consume the data and do the >> next read). I'm not sure nginx will find this but so useful as web servers >> tend to send a lot more data than they receive. The only software I have >> patched explicitly for this is netperf. > > Hm, this is like only aio_read() on sokets give performance boost, not > aio_write()? >
Both. tx_zcopy is the knob for aio_write and ddp is the knob for aio_read. ddp will probably get renamed to rx_zcopy (while still working with the 'ddp' name for backward compat). _______________________________________________ svn-src-all@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscr...@freebsd.org"
