Differential D12447

Some cache related optimizations
ClosedPublic
Actions

Authored by shurd on Sep 21 2017, 10:20 PM.

Details

Reviewers

sbruno

Commits

rS324937: Some cache related optimizations

Summary

prefetch 128 bytes of mbufs.
Re-order filling the pkt_info so cache stalls happen at the end
Define empty prefetch2() macro when the function isn't present.

Provides small performance improvments on some hardware

Test Plan

Test on a wider range of hardware for regressions

Diff Detail

Repository

rS FreeBSD src repository - subversion

Lint

Lint Passed

Unit

No Test Coverage

Build Status

Buildable 11667
Build 12013: arc lint + arc unit

Event Timeline

shurd created this revision.Sep 21 2017, 10:20 PM

Herald added subscribers: ae, imp. · View Herald TranscriptSep 21 2017, 10:20 PM

Harbormaster completed remote builds in B11667: Diff 33289.Sep 21 2017, 10:20 PM

Is there a reason that we don't modify prefetch() instead of creating a new prefetch2() function?

In D12447#258276, @sbruno wrote:

Is there a reason that we don't modify prefetch() instead of creating a new prefetch2() function?

The majority of places prefetch() is used don't need the extra cacheline prefetched.

Ok, lets rename prefetch2() to something that indicates why there is a second function (being a bit pedantic here). something like prefetch_align() or whatever.

This revision now requires changes to proceed.Sep 27 2017, 6:47 PM

In D12447#259600, @sbruno wrote:

Ok, lets rename prefetch2() to something that indicates why there is a second function (being a bit pedantic here). something like prefetch_align() or whatever.

Do you like prefetch2cachelines() better?

In D12447#261301, @shurd wrote:

In D12447#259600, @sbruno wrote:

Ok, lets rename prefetch2() to something that indicates why there is a second function (being a bit pedantic here). something like prefetch_align() or whatever.

Do you like prefetch2cachelines() better?