(Note that this patch set depends on virtual ISM support, which is under review: https://lore.kernel.org/netdev/1702021259-41504-1-git-send-email-guwen@xxxxxxxxxxxxxxxxx/) This patch set acts as the second part of the new version of [1], the updated things of this version are listed at the end. # Background SMC-D is now used in IBM z with ISM function to optimize network interconnect for intra-CPC communications. Inspired by this, we try to make SMC-D available on the non-s390 architecture through a software-implemented virtual ISM device, that is the loopback-ism device here, to accelerate inter-process or inter-containers communication within the same OS instance. # Design This patch set includes 3 parts: - Patch #1-#2: some prepare work for loopback-ism. - Patch #3-#9: implement loopback-ism device. - Patch #10-#13: memory copy optimization for loopback scenario. The loopback-ism device is designed as a 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. 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 | | +---------------------------+--------------+-----------------------------+ loopback-ism device creates DMBs (shared memory) for each connection peer. Since data transfer occurs within the same kernel, the sndbuf of each peer 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. 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 | | +---------------------------+--------------+-----------------------------+ # Benchmark Test * Test environments: - VM with Intel Xeon Platinum 8 core 2.50GHz, 16 GiB mem. - SMC sndbuf/DMB size 1MB. * Test object: - TCP: run on TCP loopback. - domain: run on UNIX domain. - SMC lo: run on SMC loopback device. 1. ipc-benchmark (see [2]) - ./<foo> -c 1000000 -s 100 TCP SMC-lo Message rate (msg/s) 81539 151251(+85.50%) 2. sockperf - serv: <smc_run> taskset -c <cpu> sockperf sr --tcp - clnt: <smc_run> taskset -c <cpu> sockperf { tp | pp } --tcp --msg-size={ 64000 for tp | 14 for pp } -i 127.0.0.1 -t 30 TCP SMC-lo Bandwidth(MBps) 5313.66 8270.51(+55.65%) Latency(us) 5.806 3.207(-44.76%) 3. nginx/wrk - serv: <smc_run> nginx - clnt: <smc_run> wrk -t 8 -c 1000 -d 30 http://127.0.0.1:80 TCP SMC-lo Requests/s 194641.79 258656.13(+32.89%) 4. redis-benchmark - serv: <smc_run> redis-server - clnt: <smc_run> redis-benchmark -h 127.0.0.1 -q -t set,get -n 400000 -c 200 -d 1024 TCP SMC-lo GET(Requests/s) 85855.34 115640.35(+34.69%) SET(Requests/s) 86337.15 118203.30(+36.90%) [1] https://lore.kernel.org/netdev/1695568613-125057-1-git-send-email-guwen@xxxxxxxxxxxxxxxxx/ [2] https://github.com/goldsborough/ipc-bench Updated in this version compare to [1]: - Patch #1: improve the loopback-ism dump, it shows as follows now: # smcd d FID Type PCI-ID PCHID InUse #LGs PNET-ID 0000 0 loopback-ism ffff No 0 - Patch #3: introduce the smc_ism_set_v2_capable() helper and set smc_ism_v2_capable when ISMv2 or virtual ISM is registered, regardless of whether there is already a device in smcd device list. - Patch #3: loopback-ism will be added into /sys/devices/virtual/smc/loopback-ism/. - Patch #8: introduce the runtime switch /sys/devices/virtual/smc/loopback-ism/active to activate or deactivate the loopback-ism. - Patch #9: introduce the statistics of loopback-ism by /sys/devices/virtual/smc/loopback-ism/{{tx|rx}_tytes|dmbs_cnt}. - Some minor changes and comments improvements. Wen Gu (13): net/smc: improve SMC-D device dump for virtual ISM net/smc: decouple specialized struct from SMC-D DMB registration net/smc: introduce virtual ISM device loopback-ism net/smc: implement ID-related operations of loopback-ism net/smc: implement some unsupported operations of loopback-ism net/smc: implement DMB-related operations of loopback-ism net/smc: register loopback-ism into SMC-D device list net/smc: introduce loopback-ism runtime switch net/smc: introduce loopback-ism statistics attributes net/smc: introduce operations to {at|de}tach ghost sndbuf to peer DMB net/smc: attach or detach ghost sndbuf to peer DMB. net/smc: adapt cursor update when sndbuf is mapped to peer DMB net/smc: implement {at|de}tach_dmb interfaces of loopback-ism drivers/s390/net/ism_drv.c | 2 +- include/net/smc.h | 6 +- net/smc/Kconfig | 13 + net/smc/Makefile | 2 +- net/smc/af_smc.c | 33 ++- net/smc/smc_cdc.c | 58 ++++- net/smc/smc_cdc.h | 1 + net/smc/smc_core.c | 71 +++++- net/smc/smc_core.h | 1 + net/smc/smc_ism.c | 69 +++++- net/smc/smc_ism.h | 5 + net/smc/smc_loopback.c | 603 +++++++++++++++++++++++++++++++++++++++++++++ net/smc/smc_loopback.h | 80 ++++++ 13 files changed, 915 insertions(+), 29 deletions(-) create mode 100644 net/smc/smc_loopback.c create mode 100644 net/smc/smc_loopback.h -- 1.8.3.1
