[EXTERNAL] [PATCH] app/crypto-perf-test: fix unset crc algorithm

[Akhil Goyal]

> > Subject: RE: [EXTERNAL] [PATCH] app/crypto-perf-test: fix unset crc algorithm
> >
> > > Because net crc api is not thread-safe, setting crc algorithm by the
> > > application will prevent race condition in the calc function.
> > > Race condition still may occur when any of the threads will call this
> > > function again. Function is called with the highest possible SIMD
> > > extension, which is AVX512, but if this is not found, CRC API will
> > > pick the other highest possible extension, or scalar if no SIMD
> > > available.
> > >
> > > Fixes: f8be1786b1b8 ("app/crypto-perf: introduce performance test
> > > application")
> > >
> > > Signed-off-by: Arkadiusz Kusztal <arkadiuszx.kusztal at intel.com>
> > > ---
> > >  app/test-crypto-perf/main.c | 3 +++
> > >  1 file changed, 3 insertions(+)
> > >
> > > diff --git a/app/test-crypto-perf/main.c b/app/test-crypto-perf/main.c
> > > index 40c0b4b54f..58496797d7 100644
> > > --- a/app/test-crypto-perf/main.c
> > > +++ b/app/test-crypto-perf/main.c
> > > @@ -11,6 +11,7 @@
> > >  #include <rte_eal.h>
> > >  #include <rte_errno.h>
> > >  #include <rte_cryptodev.h>
> > > +#include <rte_net_crc.h>
> > >  #ifdef RTE_CRYPTO_SCHEDULER
> > >  #include <rte_cryptodev_scheduler.h>
> > >  #endif
> > > @@ -599,6 +600,8 @@ main(int argc, char **argv)
> > >  		goto err;
> > >  	}
> > >
> > > +	rte_net_crc_set_alg(RTE_NET_CRC_AVX512);
> > > +
> > >  	ret = cperf_verify_devices_capabilities(&opts, enabled_cdevs,
> > >  			nb_cryptodevs);
> > >  	if (ret) {
> > > --
> > Not sure what is the use of this API here.
> > Which calc function is it fixing.
> 
> Yes, this deserves some explanation, rte_net_crc_calc function, when alg not set,
> will first try to set it during the first run.
> Yet it is done in thread-unsafe manner, causing perf-test to most likely segfault
> because of that, when more than one thread used.
> 
Still it is not clear. Which use case of test-crypto-perf need setting this?
If it is specific to a usecase, then it should be under checks or it should be inside PMD.

> >
> > Also will it ever pick neon handler?
> 
> No, it won't, currently only qat is using this api though.
> This api needs to be fixed, so eventually this will look different, but for now, not
> many choices available.