From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 109221 invoked by alias); 25 Sep 2019 07:03:41 -0000 Mailing-List: contact newlib-cvs-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: newlib-cvs-owner@sourceware.org Received: (qmail 109203 invoked by uid 10080); 25 Sep 2019 07:03:41 -0000 Date: Wed, 25 Sep 2019 07:03:00 -0000 Message-ID: <20190925070341.109202.qmail@sourceware.org> Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit From: Sebastian Huber To: newlib-cvs@sourceware.org Subject: [newlib-cygwin] Add an external mbuf buffer type that holds X-Act-Checkin: newlib-cygwin X-Git-Author: jhb X-Git-Refname: refs/heads/master X-Git-Oldrev: d41e144869ca8f89fb42692b0858a2310c1df407 X-Git-Newrev: 2f55e1fa06fc0236cc0c1a9cd3ca5f8bf9d86a65 X-SW-Source: 2019-q3/txt/msg00040.txt.bz2 https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=2f55e1fa06fc0236cc0c1a9cd3ca5f8bf9d86a65 commit 2f55e1fa06fc0236cc0c1a9cd3ca5f8bf9d86a65 Author: jhb Date: Sat Jun 29 00:48:33 2019 +0000 Add an external mbuf buffer type that holds multiple unmapped pages. Unmapped mbufs allow sendfile to carry multiple pages of data in a single mbuf, without mapping those pages. It is a requirement for Netflix's in-kernel TLS, and provides a 5-10% CPU savings on heavy web serving workloads when used by sendfile, due to effectively compressing socket buffers by an order of magnitude, and hence reducing cache misses. For this new external mbuf buffer type (EXT_PGS), the ext_buf pointer now points to a struct mbuf_ext_pgs structure instead of a data buffer. This structure contains an array of physical addresses (this reduces cache misses compared to an earlier version that stored an array of vm_page_t pointers). It also stores additional fields needed for in-kernel TLS such as the TLS header and trailer data that are currently unused. To more easily detect these mbufs, the M_NOMAP flag is set in m_flags in addition to M_EXT. Various functions like m_copydata() have been updated to safely access packet contents (using uiomove_fromphys()), to make things like BPF safe. NIC drivers advertise support for unmapped mbufs on transmit via a new IFCAP_NOMAP capability. This capability can be toggled via the new 'nomap' and '-nomap' ifconfig(8) commands. For NIC drivers that only transmit packet contents via DMA and use bus_dma, adding the capability to if_capabilities and if_capenable should be all that is required. If a NIC does not support unmapped mbufs, they are converted to a chain of mapped mbufs (using sf_bufs to provide the mapping) in ip_output or ip6_output. If an unmapped mbuf requires software checksums, it is also converted to a chain of mapped mbufs before computing the checksum. Submitted by: gallatin (earlier version) Reviewed by: gallatin, hselasky, rrs Discussed with: ae, kp (firewalls) Relnotes: yes Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D20616 Diff: --- newlib/libc/sys/rtems/include/net/if.h | 1 + 1 file changed, 1 insertion(+) diff --git a/newlib/libc/sys/rtems/include/net/if.h b/newlib/libc/sys/rtems/include/net/if.h index a9b875c..a60374d 100644 --- a/newlib/libc/sys/rtems/include/net/if.h +++ b/newlib/libc/sys/rtems/include/net/if.h @@ -246,6 +246,7 @@ struct if_data { #define IFCAP_HWSTATS 0x800000 /* manages counters internally */ #define IFCAP_TXRTLMT 0x1000000 /* hardware supports TX rate limiting */ #define IFCAP_HWRXTSTMP 0x2000000 /* hardware rx timestamping */ +#define IFCAP_NOMAP 0x4000000 /* can TX unmapped mbufs */ #define IFCAP_HWCSUM_IPV6 (IFCAP_RXCSUM_IPV6 | IFCAP_TXCSUM_IPV6)