In D7073#104561, @martinvonz wrote:

Should no longer be necessary with D7123, right?

In D7121#104675, @marmoute wrote:

In D7121#104674, @martinvonz wrote:

In D7121#104673, @marmoute wrote:

In D7121#104672, @martinvonz wrote:

In D7121#104671, @marmoute wrote:

In D7121#104546, @martinvonz wrote:

[…]

So there seems to be a measurable difference. Could just the function call overhead be that whole difference? Anyway, it doesn't seem worth spending time trying to figure out.

Function call can have a large overhead, how many revision are we talking about here ?

5627

That is not much to be honest. How do you measure this?

By running exactly the command I shared earlier :P This is a version of mozilla-unified I've created by running hg convert --config experimental.copies.write-to=changeset-only.

I meant the number of changeset :-)

In D7121#104674, @martinvonz wrote:

In D7121#104673, @marmoute wrote:

In D7121#104672, @martinvonz wrote:

In D7121#104671, @marmoute wrote:

In D7121#104546, @martinvonz wrote:

[…]

So there seems to be a measurable difference. Could just the function call overhead be that whole difference? Anyway, it doesn't seem worth spending time trying to figure out.

Function call can have a large overhead, how many revision are we talking about here ?

5627

That is not much to be honest. How do you measure this?

By running exactly the command I shared earlier :P This is a version of mozilla-unified I've created by running hg convert --config experimental.copies.write-to=changeset-only.

In D7121#104672, @martinvonz wrote:

In D7121#104671, @marmoute wrote:

In D7121#104546, @martinvonz wrote:

[…]

So there seems to be a measurable difference. Could just the function call overhead be that whole difference? Anyway, it doesn't seem worth spending time trying to figure out.

Function call can have a large overhead, how many revision are we talking about here ?

5627

In D7121#104546, @martinvonz wrote:

In D7121#104543, @martinvonz wrote:

Performance measurement does not show any significant performance movement. This
is not surprising since p1copies() code is self._copies[0].

My testing agrees with that. However, making the same change (well, the reverse of it) on top of D7070 makes very significant difference. I have no idea why.

Actually, I may have spoken too soon. hg perfpathcopies FIREFOX_BETA_59_END FIREFOX_BETA_60_BASE --config perf.run-limits='10.0-10' yields:

before:
! wall 4.595685 comb 4.600000 user 4.530000 sys 0.070000 (best of 10)
after:
! wall 4.485065 comb 4.490000 user 4.440000 sys 0.050000 (best of 10)

So there seems to be a measurable difference. Could just the function call overhead be that whole difference? Anyway, it doesn't seem worth spending time trying to figure out.

I splitted the usage of changelog.parent out of the extraction of revinfo to measure things further. That step give a small perf boost.
Adding a function call comes with a tiny performance cost:

In D7070#104172, @martinvonz wrote:

In D7070#104170, @martinvonz wrote:

In D7070#104159, @marmoute wrote:

In D7070#104100, @martinvonz wrote:

The extracted function slows down hg perfpathcopies FIREFOX_BETA_59_END FIREFOX_BETA_60_BASE (not merge-heavy) from 3.55s to 3.87s, but since you also changed ctx.p[12]copies() to ctx._copies it ended up being a net speed improvement (3.24s including for the patch as written).

Which method are you using on this repository ? extra+changeset-only ?

Yes.

Sorry, I should say that that's of course I version of mozilla-unified that I've converted. Let me know if you want a copy of it, but I suspect that you'll see similar numbers in your repos.

In D7070#104100, @martinvonz wrote:

The extracted function slows down hg perfpathcopies FIREFOX_BETA_59_END FIREFOX_BETA_60_BASE (not merge-heavy) from 3.55s to 3.87s, but since you also changed ctx.p[12]copies() to ctx._copies it ended up being a net speed improvement (3.24s including for the patch as written).