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Differential D33131

pf: add pf_bcmp_state_key
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Authored by mjg on Nov 26 2021, 3:09 PM.
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farrokhi
glebius
imp
melifaro

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kp
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rG170821d5241f: pf: add pf_bcmp_state_key
rGb6c8c7b99a75: pf: add pf_bcmp_state_key
Summary

The comparison size of 40 bytes is known at compilation time but clang refuses to optimize it, thus hand-roll a short variant.

Benchmarked on a kernel with other changes on top of it. Interestingly it fails to provide a speed up, but instead it shifts CPU time elsewhere.

before: https://people.freebsd.org/~mjg/pf_nohashrow.svg
after: https://people.freebsd.org/~mjg/pf_nohashrow_custom_bcmp.svg

You can see time in netisr_dispatch -> ip_input -> ip_tryforward drop from 12.19 to 10.40 of the total.

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Event Timeline

mjg created this revision.Nov 26 2021, 3:09 PM
Herald added subscribers: glebius, melifaro, farrokhi, imp. · View Herald TranscriptNov 26 2021, 3:09 PM
mjg requested review of this revision.Nov 26 2021, 3:09 PM
kp added inline comments.Nov 27 2021, 3:59 PM
sys/netpfil/pf/pf.c
431

s1ptr (and s2ptr) is not declared anywhere. Do you mean var1 = k1[0]?

433

Can't we do if (k1[0] != k2[0])?

mjg updated this revision to Diff 99077.Nov 27 2021, 4:23 PM
  • drop the temp var
mjg marked 2 inline comments as done.Nov 27 2021, 4:24 PM
mjg added inline comments.
sys/netpfil/pf/pf.c
431

i somehow upload the older version

kp accepted this revision.Nov 27 2021, 5:07 PM

There's one more in sys/netpfil/pf/pf_lb.c that could also use pf_bcmp_state_key() (in pf_get_translation()).

This revision is now accepted and ready to land.Nov 27 2021, 5:07 PM
Closed by commit rGb6c8c7b99a75: pf: add pf_bcmp_state_key (authored by mjg). · Explain WhyNov 28 2021, 7:17 PM
This revision was automatically updated to reflect the committed changes.
mjg marked an inline comment as done.
mjg added a commit: rGb6c8c7b99a75: pf: add pf_bcmp_state_key.
mjg added a commit: rG170821d5241f: pf: add pf_bcmp_state_key.Aug 2 2022, 8:05 PM

Revision Contents
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PathSize
sys/
netpfil/
pf/
40 lines

Diff 99077

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sys/netpfil/pf/pf.c

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