Hi Matt, I’d say that trying to cover all possible combinations of POSIX calls is the main issue. Also, statically linked applications won’t work fine with ld_preload. But, I’ll let Dave provide more details since he is more closely involved with the effort.
Florin > On Jul 31, 2018, at 7:01 AM, Matthew Smith <mgsm...@netgate.com> wrote: > > > Hi Florin and Dave, > > I’m curious what problems were observed with the LD_PRELOAD mechanism. Were > there performance issues? Or was it too difficult to try and cover different > usage of POSIX calls? Or something else? > > Thanks! > -Matt > > >> On Jul 30, 2018, at 10:39 AM, Florin Coras <fcoras.li...@gmail.com >> <mailto:fcoras.li...@gmail.com>> wrote: >> >> Prashant, >> >> Dave is exactly right. If you still want to try out the LDP layer, I >> wouldn’t set a global LD_PRELOAD variable because that will end up >> preloading all the applications and, inevitably, to some unsupported usage >> patterns and crashes. Instead, start only your app with LD_PRELOAD set, >> something like: >> >> LD_PRELOAD=../vpp/build-root/install-vpp_debug-native/vpp/lib64/libvcl_ldpreload.so >> <your_app> >> >> Note that we’re exercising both the vcl and ldp layers with our test >> infrastructure. So, you may also want to take a look at test_vcl for more >> details on how we use the ldp layer. >> >> Hope this helps, >> Florin >> >> >>> On Jul 30, 2018, at 8:09 AM, Dave Wallace <dwallac...@gmail.com >>> <mailto:dwallac...@gmail.com>> wrote: >>> >>> Prashant, >>> >>> The VCL LD_PRELOAD library is experimental and only works with a very >>> limited set of legacy POSIX sockets applications (and only with single >>> workers). >>> >>> The conclusion based on the results of the initial experimentation with >>> LD_PRELOAD is that it is not a viable mechanism for accelerating legacy >>> POSIX sockets based applications using the VPP host stack. The current >>> recommendation is to refactor legacy applications to use the VCL API >>> directly. >>> >>> You should also be aware that the VCL infrastructure is in the middle of >>> being refactored at this time and thus the VCL API may change. I'll let >>> Florin, who is doing the refactoring, add his input on the VCL API roadmap. >>> >>> Thanks, >>> -daw- >>> >>> On 7/30/2018 7:21 AM, Prashant Upadhyaya wrote: >>>> Hi, >>>> >>>> I have compiled VPP and it's running. I have an interface up and can >>>> ping the IP applied there. >>>> >>>> Now I am trying to bring up a legacy application TCP server (the one >>>> which uses POSIX calls). So I set the LD_PRELOAD to point to >>>> .../vpp/build-root/install-vpp_debug-native/vpp/lib64/libvcl_ldpreload.so >>>> But the server application now crashes on startup. >>>> Even the ldd command starts crashing. >>>> >>>> Can somebody point me to the correct set of steps to be used for >>>> LD_PRELOAD to bring up my legacy tcp server which will then engage the >>>> VPP TCP stack instead of the kernel's >>>> >>>> Regards >>>> -Prashant >>>> >>>> >>>> -=-=-=-=-=-=-=-=-=-=-=- >>>> Links: You receive all messages sent to this group. >>>> >>>> View/Reply Online (#9971): https://lists.fd.io/g/vpp-dev/message/9971 >>>> <https://lists.fd.io/g/vpp-dev/message/9971> >>>> Mute This Topic: https://lists.fd.io/mt/23858819/675079 >>>> <https://lists.fd.io/mt/23858819/675079> >>>> Group Owner: vpp-dev+ow...@lists.fd.io <mailto:vpp-dev+ow...@lists.fd.io> >>>> Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub >>>> <https://lists.fd.io/g/vpp-dev/unsub> [dwallac...@gmail.com >>>> <mailto:dwallac...@gmail.com>] >>>> -=-=-=-=-=-=-=-=-=-=-=- >>> >>> -=-=-=-=-=-=-=-=-=-=-=- >>> Links: You receive all messages sent to this group. >>> >>> View/Reply Online (#9973): https://lists.fd.io/g/vpp-dev/message/9973 >>> <https://lists.fd.io/g/vpp-dev/message/9973> >>> Mute This Topic: https://lists.fd.io/mt/23858819/675152 >>> <https://lists.fd.io/mt/23858819/675152> >>> Group Owner: vpp-dev+ow...@lists.fd.io <mailto:vpp-dev+ow...@lists.fd.io> >>> Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub >>> <https://lists.fd.io/g/vpp-dev/unsub> [fcoras.li...@gmail.com >>> <mailto:fcoras.li...@gmail.com>] >>> -=-=-=-=-=-=-=-=-=-=-=- >> >> -=-=-=-=-=-=-=-=-=-=-=- >> Links: You receive all messages sent to this group. >> >> View/Reply Online (#9974): https://lists.fd.io/g/vpp-dev/message/9974 >> <https://lists.fd.io/g/vpp-dev/message/9974> >> Mute This Topic: https://lists.fd.io/mt/23858819/675725 >> <https://lists.fd.io/mt/23858819/675725> >> Group Owner: vpp-dev+ow...@lists.fd.io <mailto:vpp-dev+ow...@lists.fd.io> >> Unsubscribe: https://lists.fd.io/g/vpp-dev/unsub >> <https://lists.fd.io/g/vpp-dev/unsub> [mgsm...@netgate.com >> <mailto:mgsm...@netgate.com>] >> -=-=-=-=-=-=-=-=-=-=-=- >
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