Is it the same OS/kernel version in both cases? Sent from my iPhone
> On Oct 11, 2022, at 5:53 PM, zhou <[email protected]> wrote: > > > Hi Marcus, > > I haven't tried UHD 4.2 or 4.3. I see ULLL sometimes in new system, so > actually I am thinking reverting UHD back to the 3.10. > > > > > On Tuesday, 11 October 2022 at 21:47:30 BST, Marcus D. Leech > <[email protected]> wrote: > > >> On 2022-10-11 16:23, zhou wrote: >> Thanks Marcus. Yes, I use the get_time_now function to read time inside >> USRPs. >> >> I also think the newer UHD versions should be better, but the measurements >> tell differently. The queries to USRPs are sequential. >> There are 16 USRPs using UHD 4.1.0. I query them sequentially and the time >> intervals one example is as follows (unit: ms): >> 1.683691 >> 1.606288 >> 1.629145 >> 1.790804 >> 1.685894 >> 1.736507 >> 1.471674 >> 1.424962 >> 1.460004 >> 1.403206 >> 1.435221 >> 1.394569 >> 2.043707 >> 1.509543 >> 1.853792 >> >> In old system, 24 USRPs use UHD 3.10. The time intervals in one example is >> (unit: ms): >> 0.385173 >> 0.296745 >> 0.284212 >> 0.273682 >> 0.278543 >> 0.274327 >> 0.279519 >> 0.274441 >> 0.276693 >> 0.296875 >> 0.275212 >> 0.307623 >> 0.309554 >> 0.28233 >> 0.28234 >> 0.275119 >> 0.283057 >> 0.277138 >> 0.279357 >> 0.276074 >> 0.277696 >> 0.276335 >> 0.280675 >> >> >> Though there is some variance in intervals in both systems, the difference >> between old and new systems are significant and reliable. >> Could you please pass my case to the R&D team to confirm? >> >> Thanks, >> Hongwei >> >> >> >> On Tuesday, 11 October 2022 at 18:35:24 BST, Marcus D. Leech >> <[email protected]> wrote: >> >> >> On 2022-10-11 12:15, zhou via USRP-users wrote: >> >> Hi, >> >> Some of our USRPs are using UHD 3.10 because they are in old systems. and I >> am also using UHD 4.1.0 in some other USRPs in new system. The USRP products >> are all NI USRP 2944 (X310). >> In my applications, I need to use PPS signal to synchronize multiple USRPs. >> After applying PPS signals, I read back the time in USRPs one by one. >> Because of network delay, there is some difference between the readings. >> However, the difference is much bigger in UHD 4.1.0. >> >> The interval between two USRPs using UHD 3.10 is about 0.2ms while it is >> about 1.4ms in UHD 4.1.0 >> >> Does this mean that UHD 4.1.0 is slower than UHD 3.10? >> >> Thanks for any suggestion, >> >> Hongwei >> > Have you tried UHD 4.2 or UHD 4.3? > > I'll point out that the performance-critical aspect is the streaming > performance. The latency on get_time_now() shouldn't matter > that much, unless you're trying to use it for synchronization, and you > really should be doing that. That's what set_time_next_pps() > and friends are for. > > > _______________________________________________ > USRP-users mailing list -- [email protected] > To unsubscribe send an email to [email protected]
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