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
_______________________________________________
USRP-users mailing list -- [email protected]
To unsubscribe send an email to [email protected]
When you say "read back the time", you're presumably using "get_time_now()",
which is nearly-guaranteed to return different
results from different USRPs queried serially, since it's returning a
*snapshot* of the time-of-day-clock in each USRP, and if
you're querying them serially, there'll be some unpredictable-but-bounded
time for each of those transactions to complete.
It's unlikely that UHD 4.1 has significant performance regressions compared to
UHD 3.10, but UHD 3.10 is old, and things
like command-packet handling may be quite different between those two
versions.
_______________________________________________
USRP-users mailing list -- [email protected]
To unsubscribe send an email to [email protected]
_______________________________________________
USRP-users mailing list -- [email protected]
To unsubscribe send an email to [email protected]
