Hi Michael, Thanks for looking at the profiles. I must confess that I didn't know about the --diff_base option. I'll take a closer look at the results of the diff and see if that can help me spot anything.
In answer to your questions: I'm certain these profiles were produced from the same source code and I'm also certain that the same amount of logical work was being done. I can rerun the tests and reproduce the results. I'll raise an GitHub issue tomorrow if nothing else comes to light. Thanks again Stephen On Friday 9 February 2024 at 22:16:10 UTC Michael Knyszek wrote: > Hey Stephen, > > I poked at your profiles (diffing them) but my only guess is that it's a > compiler change that's the culprit. (For future reference, I produced this > output with the --diff_base flag, which subtracts one profile from > another.) > > Showing nodes accounting for -1.34s, 0.44% of 305.86s total > Dropped 4 nodes (cum <= 1.53s) > Showing top 20 nodes out of 248 > flat flat% sum% cum cum% > -2.85s 0.93% 0.93% -2.89s 0.94% > github.com/jetsetilly/gopher2600/hardware/tia/audio.(*Audio).Step > -2.80s 0.92% 1.85% -1.68s 0.55% > github.com/jetsetilly/gopher2600/hardware/tia.(*TIA).QuickStep > 1.52s 0.5% 1.35% 1.91s 0.62% > github.com/jetsetilly/gopher2600/hardware/tia/video.(*Video).Pixel > 1.27s 0.42% 0.94% 2.04s 0.67% > github.com/jetsetilly/gopher2600/hardware/tia/video.(*MissileSprite).tick > -1.18s 0.39% 1.32% -1.18s 0.39% > github.com/jetsetilly/gopher2600/hardware/memory/cartridge.(*Cartridge).AccessPassive > > (inline) > -0.84s 0.27% 1.60% -0.99s 0.32% > github.com/jetsetilly/gopher2600/hardware/tia/video.(*PlayerSprite).tick > 0.67s 0.22% 1.38% 1.24s 0.41% > github.com/jetsetilly/gopher2600/hardware/cpu.(*CPU).read8Bit > 0.61s 0.2% 1.18% 1.46s 0.48% > github.com/jetsetilly/gopher2600/hardware/tia/video.(*Video).Tick > -0.54s 0.18% 1.35% -0.59s 0.19% > github.com/jetsetilly/gopher2600/hardware/memory/cartridge.(*atari4k).Access > -0.54s 0.18% 1.53% -0.51s 0.17% > github.com/jetsetilly/gopher2600/hardware/tia/video.(*PlayerSprite).pixel > 0.49s 0.16% 1.37% 0.49s 0.16% > github.com/jetsetilly/gopher2600/hardware/memory/memorymap.MapAddress > (inline) > 0.47s 0.15% 1.22% 0.60s 0.2% > github.com/jetsetilly/gopher2600/hardware/memory/cartridge.(*Cartridge).Write > (inline) > 0.47s 0.15% 1.06% 1.32s 0.43% > github.com/jetsetilly/gopher2600/hardware/riot/timer.(*Timer).Step > 0.41s 0.13% 0.93% 0.41s 0.13% > github.com/jetsetilly/gopher2600/hardware/memory/vcs.(*RIOTMemory).ChipRefer > 0.40s 0.13% 0.8% 0.44s 0.14% > github.com/jetsetilly/gopher2600/hardware/tia/video.(*MissileSprite).pixel > 0.39s 0.13% 0.67% 0.39s 0.13% > github.com/jetsetilly/gopher2600/hardware/memory/vcs.(*RIOTMemory).ChipHasChanged > 0.36s 0.12% 0.55% 0.62s 0.2% > github.com/jetsetilly/gopher2600/hardware/riot/ports.(*Ports).Step > 0.35s 0.11% 0.44% 0.35s 0.11% > github.com/jetsetilly/gopher2600/hardware/tia/video.(*BallSprite).pixel > -0.33s 0.11% 0.55% -0.59s 0.19% > github.com/jetsetilly/gopher2600/hardware/tia/video.(*BallSprite).tick > 0.33s 0.11% 0.44% 0.85s 0.28% > github.com/jetsetilly/gopher2600/hardware/tia/video.(*MissileSprite).tickHMOVE > > A couple questions just so we're on the same page: > - Are you certain these two profiles were produced from the same source > code? > - Are you certain these two profiles represent the same amount of logical > work being done? (As an example, in the context of a web service, I > wouldn't want to measure 30s of traffic, but rather N identical requests > handled to make an apples-to-apples comparison.) > > If yes to both, then I think my conclusion is that this is probably the > result of a compiler change, given that the flat time increases all seem to > come from "user" code (as opposed to, say, runtime code). > > Do you have a reproducer? It might be worth filing a GitHub issue at this > point. (https://github.com/golang/go/issues/new/choose) > > Thanks, > Michael > > On Friday, February 9, 2024 at 3:13:12 PM UTC-5 Stephen Illingworth wrote: > >> Hello, >> >> I'm trying v1.22.0 and I'm measuring an approximate drop in performance >> of 10%. I'm comparing to v1.21.7 >> >> I'm looking at the release notes but I can't see anything that I would >> think would be having an impact. Is anyone else noticing a performance drop? >> >> I've created a cpu.profile for my project for each the two go versions. >> >> I can't see anything obviously different between the two profiles but >> then again, I'm not very skilled with pprof. I've uploaded them to github >> if anyone wants to help. >> >> https://github.com/JetSetIlly/gopher2600_performance_profiles >> >> >> Regards >> Stephen >> > -- You received this message because you are subscribed to the Google Groups "golang-nuts" group. To unsubscribe from this group and stop receiving emails from it, send an email to golang-nuts+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/golang-nuts/4ac9cd6d-1d38-4384-b7ad-13a290916ce8n%40googlegroups.com.
