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[146.241.226.128]) by smtp.gmail.com with ESMTPSA id je20-20020a05600c1f9400b004131fb3bac4sm11811900wmb.17.2024.03.12.08.00.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 12 Mar 2024 08:00:24 -0700 (PDT) Message-ID: <29944ce3f034f5373a99b2dcb0d5a5cef906e28e.camel@redhat.com> Subject: Re: [PATCH net-next v3 00/11] net/smc: SMC intra-OS shortcut with loopback-ism From: Paolo Abeni To: Wen Gu , wintera@linux.ibm.com, twinkler@linux.ibm.com, hca@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, wenjia@linux.ibm.com, jaka@linux.ibm.com Cc: borntraeger@linux.ibm.com, svens@linux.ibm.com, alibuda@linux.alibaba.com, tonylu@linux.alibaba.com, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, netdev@vger.kernel.org Date: Tue, 12 Mar 2024 16:00:22 +0100 In-Reply-To: <20240312142743.41406-1-guwen@linux.alibaba.com> References: <20240312142743.41406-1-guwen@linux.alibaba.com> Autocrypt: addr=pabeni@redhat.com; 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charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.50.4 (3.50.4-1.fc39) Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2024-03-12 at 22:27 +0800, Wen Gu wrote: > This patch set acts as the second part of the new version of [1] (The fir= st > part can be referred from [2]), the updated things of this version are li= sted > at the end. >=20 > - Background >=20 > SMC-D is now used in IBM z with ISM function to optimize network intercon= nect > for intra-CPC communications. Inspired by this, we try to make SMC-D avai= lable > on the non-s390 architecture through a software-implemented Emulated-ISM = device, > that is the loopback-ism device here, to accelerate inter-process or > inter-containers communication within the same OS instance. >=20 > - Design >=20 > This patch set includes 3 parts: >=20 > - Patch #1-#2: some prepare work for loopback-ism. > - Patch #3-#7: implement loopback-ism device. Noted that loopback-ism no= w > serves only SMC and no userspace interface exposed. > - Patch #10-#15: memory copy optimization for intra-OS scenario. >=20 > The loopback-ism device is designed as an ISMv2 device and not be limited= to > a specific net namespace, ends of both inter-process connection (1/1' in = diagram > below) or inter-container connection (2/2' in diagram below) can find the= same > available loopback-ism and choose it during the CLC handshake. >=20 > Container 1 (ns1) Container 2 (ns2) > +-----------------------------------------+ +------------------------= -+ > | +-------+ +-------+ +-------+ | | +-------+ = | > | | App A | | App B | | App C | | | | App D |<-+ = | > | +-------+ +---^---+ +-------+ | | +-------+ |(2')= | > | |127.0.0.1 (1')| |192.168.0.11 192.168.0.12| = | > | (1)| +--------+ | +--------+ |(2) | | +--------+ +--------+= | > | `-->| lo |-` | eth0 |<-` | | | lo | | eth0 |= | > +---------+--|---^-+---+-----|--+---------+ +-+--------+---+-^------+= -+ > | | | | > Kernel | | | | > +----+-------v---+-----------v----------------------------------+---+---= -+ > | | TCP | = | > | | | = | > | +--------------------------------------------------------------+ = | > | = | > | +--------------+ = | > | | smc loopback | = | > +---------------------------+--------------+----------------------------= -+ >=20 > loopback-ism device creates DMBs (shared memory) for each connection peer= . > Since data transfer occurs within the same kernel, the sndbuf of each pee= r > is only a descriptor and point to the same memory region as peer DMB, so = that > the data copy from sndbuf to peer DMB can be avoided in loopback-ism case= . >=20 > Container 1 (ns1) Container 2 (ns2) > +-----------------------------------------+ +------------------------= -+ > | +-------+ | | +-------+ = | > | | App C |-----+ | | | App D | = | > | +-------+ | | | +-^-----+ = | > | | | | | = | > | (2) | | | (2') | = | > | | | | | = | > +---------------|-------------------------+ +----------|-------------= -+ > | | > Kernel | | > +---------------|-----------------------------------------|-------------= -+ > | +--------+ +--v-----+ +--------+ +--------+ = | > | |dmb_desc| |snd_desc| |dmb_desc| |snd_desc| = | > | +-----|--+ +--|-----+ +-----|--+ +--------+ = | > | +-----|--+ | +-----|--+ = | > | | DMB C | +---------------------------------| DMB D | = | > | +--------+ +--------+ = | > | = | > | +--------------+ = | > | | smc loopback | = | > +---------------------------+--------------+----------------------------= -+ >=20 > - Benchmark Test >=20 > * Test environments: > - VM with Intel Xeon Platinum 8 core 2.50GHz, 16 GiB mem. > - SMC sndbuf/DMB size 1MB. >=20 > * Test object: > - TCP: run on TCP loopback. > - SMC lo: run on SMC loopback-ism. >=20 > 1. ipc-benchmark (see [3]) >=20 > - ./ -c 1000000 -s 100 >=20 > TCP SMC-lo > Message > rate (msg/s) 81433 143938(+76.75%) >=20 > 2. sockperf >=20 > - serv: taskset -c sockperf sr --tcp > - clnt: taskset -c sockperf { tp | pp } --tcp --msg-size= =3D{ 64000 for tp | 14 for pp } -i 127.0.0.1 -t 30 >=20 > TCP SMC-lo > Bandwidth(MBps) 4903.07 7978.69(+62.73%) > Latency(us) 6.095 3.539(-41.94%) >=20 > 3. nginx/wrk >=20 > - serv: nginx > - clnt: wrk -t 8 -c 1000 -d 30 http://127.0.0.1:80 >=20 > TCP SMC-lo > Requests/s 161665.67 244272.41(+51.10%) >=20 > 4. redis-benchmark >=20 > - serv: redis-server > - clnt: redis-benchmark -h 127.0.0.1 -q -t set,get -n 400000 -= c 200 -d 1024 >=20 > TCP SMC-lo > GET(Requests/s) 88790.23 117474.30(+32.31%) > SET(Requests/s) 87508.20 118623.96(+35.57%) >=20 >=20 > Change log: >=20 > v3->v2: > - Patch #11: use tasklet_schedule(&conn->rx_tsklet) instead of smcd_cdc_r= x_handler() > to avoid possible recursive locking of conn->send_lock and use {read|wr= ite}_lock_bh() > to acquire dmb_ht_lock. >=20 > v2->v1: > Link: https://lore.kernel.org/netdev/20240307095536.29648-1-guwen@linux.a= libaba.com/ > - All the patches: changed the term virtual-ISM to Emulated-ISM as define= d by SMCv2.1. > - Patch #3: optimized the description of SMC_LO config. Avoid exposing lo= opback-ism > to sysfs and remove all the knobs until future definition clear. > - Patch #3: try to make lockdep happy by using read_lock_bh() in smc_lo_m= ove_data(). > - Patch #6: defaultly use physical contiguous DMB buffers. > - Patch #11: defaultly enable DMB no-copy for loopback-ism and free the D= MB in > unregister_dmb or detach_dmb when dmb_node->refcnt reaches 0, instead o= f using > wait_event to keep waiting in unregister_dmb. >=20 > v1->RFC: > Link: https://lore.kernel.org/netdev/20240111120036.109903-1-guwen@linux.= alibaba.com/ > - Patch #9: merge rx_bytes and tx_bytes as xfer_bytes statistics: > /sys/devices/virtual/smc/loopback-ism/xfer_bytes > - Patch #10: add support_dmb_nocopy operation to check if SMC-D device su= pports > merging sndbuf with peer DMB. > - Patch #13 & #14: introduce loopback-ism device control of DMB memory ty= pe and > control of whether to merge sndbuf and DMB. They can be respectively se= t by: > /sys/devices/virtual/smc/loopback-ism/dmb_type > /sys/devices/virtual/smc/loopback-ism/dmb_copy > The motivation for these two control is that a performance bottleneck w= as > found when using vzalloced DMB and sndbuf is merged with DMB, and there= are > many CPUs and CONFIG_HARDENED_USERCOPY is set [4]. The bottleneck is ca= used > by the lock contention in vmap_area_lock [5] which is involved in memcp= y_from_msg() > or memcpy_to_msg(). Currently, Uladzislau Rezki is working on mitigatin= g the > vmap lock contention [6]. It has significant effects, but using virtual= memory > still has additional overhead compared to using physical memory. > So this new version provides controls of dmb_type and dmb_copy to suit > different scenarios. > - Some minor changes and comments improvements. >=20 ## Form letter - net-next-closed The merge window for v6.9 has begun and we have already posted our pull request. Therefore net-next is closed for new drivers, features, code refactoring and optimizations. We are currently accepting bug fixes only. Please repost when net-next reopens after March 25th. RFC patches sent for review only are obviously welcome at any time. See: https://www.kernel.org/doc/html/next/process/maintainer-netdev.html#develop= ment-cycle --=20 pw-bot: defer