Re: PVXS and CA Put benchmark

[Robby Tanner via Tech-talk <tech-talk at aps.anl.gov>]

Hi Bernardo,

If you're wanting batch "puts", does PVXS have something similar to pyepics.caput_many()...?

https://pyepics.github.io/pyepics/overview.html#epics.caput_many

I don't know enough about the differences between PVXS and CA to know if the same is possible or if it can be realized in PVXS. It might not address the specific issue you are facing.

Cheers,

Rob

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From: Tech-talk <tech-talk-bounces at aps.anl.gov> on behalf of Bernardo Brotas Carvalho via Tech-talk <tech-talk at aps.anl.gov>
Sent: April 22, 2026 11:30 AM
To: tech-talk at aps.anl.gov <tech-talk at aps.anl.gov>
Subject: PVXS and CA Put benchmark

 

Hi Epics tech-talkers,

While working on a prototype gateway to a WinCCOA  I ended up using PVXS C++ client library,

but I was a little surprised by the relatively low Throughput (when compared to a plain CA client), 

when making a bunch of "puts" to 1000 ai-PVs, served by a softIocPVX.

My first result, made on a 10 year old Intel PC where:

## PVXS Client

=== EPICS PVXS Put Benchmark: 1000 PVs ===

…

=== SUMMARY ===

  Client creation:       1.02404 ms (0.100708%)

  Put issue phase:       4.97025 ms (0.488793%)

  Wait phase:            1010.81 ms (99.4072%)

  ---------------------------------

  TOTAL TIME:            1016.84 ms

  Throughput:            983.437 puts/sec

## CA Client

=== EPICS CA Put Benchmark: 1000 PVs ===

…. 

=== SUMMARY ===

  Connect phase:         100.629 ms (95.7%)

  Put issue phase:       0.195 ms (0.2%)

  Wait phase:            4.252 ms (4.0%)

  ---------------------------------

  TOTAL TIME:            105.130 ms

  Throughput:            9512.0 puts/sec

A second test, performed on an more recent 40-core Intel(R) Xeon(R) CPU, and using PV grouping, pool, threading, etc. 

( 50 groups of ~20 PVs each), gave me ~2000 puts/sec for PVXS , but still far from CA.

My Env is:

EPICS_CA_ADDR_LIST=localhost

EPICS_CA_AUTO_ADDR_LIST=NO

EPICS_PVA_ADDR_LIST=localhost

EPICS_PVA_AUTO_ADDR_LIST=NO

EPICS_PVA_NAME_SERVERS=localhost

Am I missing something?

In case of interest, my codes made “With a Little Help From My AI Friends”, are in:

https://gitlab.com/ifmif-dones1/winccoa-epics/-/tree/pvxs/epics/pvxs/epics_benchmark

Thanks in advance

Bernardo

IPFN-IST Portugal