Messages in this thread | | | Date | Fri, 12 Jan 2024 20:32:14 +0800 | Subject | Re: [PATCH net-next 00/15] net/smc: implement loopback-ism used by SMC-D | From | Wen Gu <> |
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On 2024/1/12 17:10, Jiri Pirko wrote: > Fri, Jan 12, 2024 at 09:29:35AM CET, guwen@linux.alibaba.com wrote: >> >>
<...>
>>>> 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-#15: 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. >>>> - /sys/devices/virtual/smc/loopback-ism/dmb_copy is set to default 0, >>>> which means sndbuf and DMB are merged and no data copied between them. >>>> - /sys/devices/virtual/smc/loopback-ism/dmb_type is set to default 0, >>> >>> Exposing any configuration knobs and statistics over sysfs for >>> softdevices does not look correct at all :/ Could you please avoid >>> sysfs? >>> >> >> In previous reviews and calls, we think loopback-ism needs to be more >> like a device and be visible under /sys/devices. >> >> Would you mind explaining why using sysfs for loopback-ism is not correct? >> since I saw some other configurations or statistics exists under /sys/devices, >> e.g. /sys/devices/virtual/net/lo. Thank you! > > You have smc_netlink.c exposing clear netlink api for the subsystem. > Can't you extend it to contain the configuration knobs and expose stats > instead of sysfs? >
Thank you for the suggestion. I've also considered this approach.
But I didn't choose to extend the smc netlink because for now smc netlink are used for SMC protocol related attributes, for example:
SMC_NETLINK_GET_SYS_INFO: SMC version, release, v2-capable.. SMC_NETLINK_GET_LGR_SMC{R|D}: SMC-{R|D} link group inform (lgr id, lgr conn num, lgr role..) SMC_NETLINK_GET_LINK_SMCR: SMC-R link inform (link id, link state, conn cnt..) SMC_NETLINK_GET_DEV_SMCD: SMC-D device generic inform (user cnt, pci_fid, pci_chid, pci_vendor..) SMC_NETLINK_GET_DEV_SMCR: SMC-R device generic inform (dev name, port pnet_id, port valid, port state..) SMC_NETLINK_GET_STATS: SMC generic stats (RMB cnt, Tx size, Rx size, RMB size...)
And the knobs and stats in this patchset are loopback-ism device specific attributes, for example:
active: loopback-ism runtime switch dmb_type: type of DMB provided by loopback-ism dmb_copy: support for DMB merge of loopback-ism xfer_bytes: data transferred by loopback-ism dmbs_cnt: DMB num provided by loopback-ism
The layer will be:
+--------------------------------------+ | | | SMC protocol | | (attrs by netlink in smc_netlink.c) | | | +--------------------------------------+ ------------------smcd_ops------------------ +---------------+ +---------------------+ +--------------+ | loopback-ism | | s390 firmware ISM | | Possible | +---------------+ | | | other | (attrs by sysfs | | | virtual ISM | in smc_loopback.c) | | | | | | | | +---------------------+ +--------------+
So I choose to use current way to provide this lower layer loopback-ism device's attributes, restrict loopback-ism specific code to smc_loopback.c and try to make a clear layer architecture.
Thanks, Wen Gu > >> >> >> >> Thanks again, >> Wen Gu >> >>> >>>> which means DMB is physically contiguous buffer. >>>> >>>> * Test object: >>>> - TCP: run on TCP loopback. >>>> - SMC lo: run on SMC loopback device. >>>> >>>> 1. ipc-benchmark (see [3]) >>>> >>>> - ./<foo> -c 1000000 -s 100 >>>> >>>> TCP SMC-lo >>>> Message >>>> rate (msg/s) 80636 149515(+85.42%) >>>> >>>> 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) 4909.36 8197.57(+66.98%) >>>> Latency(us) 6.098 3.383(-44.52%) >>>> >>>> 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 181685.74 246447.77(+35.65%) >>>> >>>> 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 118553.64(+38.09%) >>>> SET(Requests/s) 86824.40 125944.58(+45.06%) >>>> >>>> >>>> Change log: >>>> >>>> v1->RFC: >>>> - 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 supports >>>> merging sndbuf with peer DMB. >>>> - Patch #13 & #14: introduce loopback-ism device control of DMB memory type and >>>> control of whether to merge sndbuf and DMB. They can be respectively set 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 was >>>> 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 caused >>>> by the lock contention in vmap_area_lock [5] which is involved in memcpy_from_msg() >>>> or memcpy_to_msg(). Currently, Uladzislau Rezki is working on mitigating 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. >>>> >>>> RFC->old version([1]): >>>> Link: https://lore.kernel.org/netdev/1702214654-32069-1-git-send-email-guwen@linux.alibaba.com/ >>>> - 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. >>>> >>>> [1] https://lore.kernel.org/netdev/1695568613-125057-1-git-send-email-guwen@linux.alibaba.com/ >>>> [2] https://lore.kernel.org/netdev/20231219142616.80697-1-guwen@linux.alibaba.com/ >>>> [3] https://github.com/goldsborough/ipc-bench >>>> [4] https://lore.kernel.org/all/3189e342-c38f-6076-b730-19a6efd732a5@linux.alibaba.com/ >>>> [5] https://lore.kernel.org/all/238e63cd-e0e8-4fbf-852f-bc4d5bc35d5a@linux.alibaba.com/ >>>> [6] https://lore.kernel.org/all/20240102184633.748113-1-urezki@gmail.com/ >>>> >>>> Wen Gu (15): >>>> 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: add operations to merge sndbuf with peer DMB >>>> net/smc: attach or detach ghost sndbuf to peer DMB >>>> net/smc: adapt cursor update when sndbuf and peer DMB are merged >>>> net/smc: introduce loopback-ism DMB type control >>>> net/smc: introduce loopback-ism DMB data copy control >>>> net/smc: implement DMB-merged operations of loopback-ism >>>> >>>> drivers/s390/net/ism_drv.c | 2 +- >>>> include/net/smc.h | 7 +- >>>> net/smc/Kconfig | 13 + >>>> net/smc/Makefile | 2 +- >>>> net/smc/af_smc.c | 28 +- >>>> net/smc/smc_cdc.c | 58 ++- >>>> net/smc/smc_cdc.h | 1 + >>>> net/smc/smc_core.c | 61 +++- >>>> net/smc/smc_core.h | 1 + >>>> net/smc/smc_ism.c | 71 +++- >>>> net/smc/smc_ism.h | 5 + >>>> net/smc/smc_loopback.c | 718 +++++++++++++++++++++++++++++++++++++ >>>> net/smc/smc_loopback.h | 88 +++++ >>>> 13 files changed, 1026 insertions(+), 29 deletions(-) >>>> create mode 100644 net/smc/smc_loopback.c >>>> create mode 100644 net/smc/smc_loopback.h >>>> >>>> -- >>>> 2.32.0.3.g01195cf9f >>>> >>>>
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