PCem

This is on a Pentium 75, Award 430VX PCI, recompiler enabled. It happens starting from this commit: https://bitbucket.org/pcem_emulator/pce ... ba296c099e , before that commit, it was fast.

Cannot reproduce. Getting a consistent 100% on P75, PMMX233, PMMX300 under Win98SE with Mach64 / AWE32

- leilei: Well, I have two people who claim they experience this slowdown. Maybe it only happens on some host CPU's? Because from what I know, I don't experience any myself, either, but they swear they do.

And I am one of them. Some DOS programs shows abnormal low performance drops (15-30% with P200) with any pentium cpu selected in actual PCem builds. I've tried Dreams to Reality and Pyl (Dust) with the PCem from 18.07.2017 (commit 16a453b). Performance stutters most noticeable at a game launch. Also in Pyl this could be easily observed anytime you bring the main menu from the game. Status window shows the drop in Real speed MIPS, but effective clock remains stable. There is no such issue with the public PCem v12 release. My host config is Intel Core i5-2500K, 16GB RAM, Nvidia GeForce GTX 780Ti, Win 10 x64.

I guess Sarah will ask for the config file, so please upload it =)

And here it is: the config file and some screens to illustrate the problem. As I can say it is not very game specific. Dreams to Reality lags much the same.

And some additional screens.

What toolchain are you using? 32-bit or 64-bit?

Could you also provide the main pcem.cfg in addition to the machine specific one.

It doesn't seem to lag on me but I have a 4790k.

The two people that reported the slowdown to me both use 32-bit binaries. Not sure what TheMadLynx used.

It is 32 bit PCem.exe built with Makefile.mingw And here is pcem.cfg attached.

Just for the sake of comparison here are screenshots of the same game running on the same machine with the last public PCem v12 build (Feb-17). Overall performance is much better and more consistent.

And here are the config file for public PCem v12.

V12's release is profile-optimized and the builds I do use -flto (link-time optimization, nowhere near pgo-speeds but close enough for quick testing and it's safe to use). Have you tried -flto?

- leilei: That has nothing to do with it... the first person that reported the bug was given a binary compiled by me on around March, with no -flto or anything, and it was at 100%. A build from around June, compiled with the exact same flags, has the slowdown. SA1988 had the same result, and he even pinpointed the exact commit that introduced it.
Maybe the fact you use -flto masks the problem. Try compiling a non-flto build and running it.

win 98 here, i get extreme slowdown in dos games, sometimes even around 4%.not always during gameplay but in menus for example or during loading.using win 98 with 64 mb, voodoo 2 and pentium 133 mmx

my main pc is I7 haswell 3.6 ghz, 16 gb ram and a geforce gtx 1050

I was never able to reproduce this issue, but rev 932 addresses what I _think_ the bug was. TheMadLynx, if you're still around, could you try this commit?

Didn't try Derby (couldn't reproduce it earlier) but that last commit did fix up some other recompiler chokers:
Jagged Alliance
Red Alert
One Must Fall 2097
Puyo Puyo 2
STTNG A Final Unity
Warcraft II
(and probably a lot more that choked Pcem's recompiler at a static screen or miles sound systems)

Does this same commit improve the issue of the recompiler choking at the Windows desktop, DOS prompt, etc.? Can't compile the latest version to check at the moment, but I'm curious. If so, that's a huge step forward!

SarahWalker wrote:I was never able to reproduce this issue, but rev 932 addresses what I _think_ the bug was. TheMadLynx, if you're still around, could you try this commit?

I've tried Pyl with 9b72b24 commit. It is not perfect but definitely a huge improvement. Game gets into main menu almost instantly, like on real hardware. Gameplay is smooth enough, like on real hardware too. But there is still odd slowdown in the main menu opened when the game is running. Nevertheless, it is a lot faster than the previous build I've tried.