Hi Nelson, Helge Deller is the expert on this and you likely will have to wait until he returns from vacation for an answer. I think the pasta buildd running hppa emulation is configured for one cpu although I could be wrong. Performance is a little slower than a real 800 MHz PA8800 machine.
Some profiling likely would be helpful. Dave On 2021-08-14 10:35 a.m., Nelson H. F. Beebe wrote: > In a previous message to the debian-hppa list today, I described how I > finally got a virtual machine successfully created for running Debian > 11 on HPPA (aka PA-RISC). > > On the same host > > Dell Precision 7920 (1 16-core CPU, 32 hyperthreads, > 2200MHz Intel Xeon Platinum 8253, > 384GB DDR-4 RAM); > Ubuntu 20.04.02 LTS (Focal Fossa) > > I have VMs running with QEMU emulation for Alpha, ARM64, M68K, MIPS32, > MIPS64, RISC-V64, S390x, and SPARC64, and most of them have quite > reasonable interactive performance, making it possible to use the > emacs editor in terminal windows and X11 windows without any serious > response problems. > > However, for the new Debian 11 HPPA VM, interactive performance is a > huge issue: shell typein sometimes gets immediate character echo, but > frequently gets delays of 10 to 30 seconds for each input character. > That makes it extremely hard for a fast typist to type commands and > text: one is never sure whether input keys have been dropped. > > I develop mathematical software, and a large package that I'm writing > for multiple precision arithmetic provides a testbed for evaluating VM > performance. Most of the QEMU CPU types support multiple processors, > but M68K and SPARC64 sun4u only permit one CPU. For HPPA, I have 4 CPUs > and 3GB DRAM; the latter is a hard limit imposed in QEMU source code. > > Here is a table of running the equivalent of > > date; make all check ; date > > on these systems, using QEMU-6.0.0, unless noted. Both compilations > and test programs are run in parallel, by internal "make -j" commands. > > make timing (wall clock) > > Debian 11 Alpha 07:43:16 -- 08:23:05 39m 49s > Debian 11 ARM64 07:58:02 -- 08:24:45 26m 43s > Debian 11 M68K 07:43:15 -- 08:30:56 47m 41s > Debian 11 HPPA 13:23:16 -- 21:40:19 497m 03s > Debian 11 HPPA 07:29:18 -- 18:07:19 638m > 01s [qemu-6.1.0-rc3] > NetBSD 9.2 HPPA 11:22:10 -- 01:25:46 843m 36s > Debian 11 MIPS32 09:21:49 -- 10:42:41 80m 52s > Debian 11 SPARC64 14:45:16 -- 06:19:00 933m 44s > Debian 11 SPARC64 17:57:58 -- 04:02:42 603m > 44s [qemu-6.1.0-rc3] > Ubuntu 18.04 S390x 18:34:34 -- 19:04:36 30m 02s > Ubuntu 20.04 S390x 18:34:35 -- 19:16:54 42m 19s > FreeBSD 13 RISC-V64 07:41:14 -- 08:34:00 52m 46s > FreeBSD 14 RISC-V64 08:35:27 -- 09:25:35 50m 08s > Fedora 34 RISC-V64 07:43:17 -- 08:02:55 19m 38s > > >From comparison, here are results on native hardware with local disk > (not NFS, unless indicated) [clock speed in GHz is abbreviated to G]: > > ArchLinux ARM32 09:57:34 -- 10:07:43 10m 09s > Debian 11 UltraSparc T2 08:30:54 -- 08:41:18 10m 24s > Solaris 10 UltraSparc T2 09:46:31 -- 09:59:32 13m 01s > Ubuntu 20.04 Xeon 8253 09:34:52 -- 09:35:36 0m 44s > CentOS 7.9 Xeon E6-1600v3 09:39:00 -- 09:39:42 0m 42s > CentOS 7.9 Xeon E6-1600v3 10:42:43 -- 10:43:30 0m > 47s [NFS] > CentOS 7.9 EPYC 7502 2.0G 64C/128T 10:02:01 -- 10:02:27 0m 26s > CentOS 7.9 EPYC 7502 2.5G 32C/64T 10:02:00 -- 10:02:25 0m 25s > > The tests produce about 62,000 total lines of text output, spread over > about 180 files. They read no input data, and are primarily compute > bound in loops with integer, not floating-point, arithmetic, using > 32-bit and 64-bit integer types. > > I have generated machine language for representative code from the > hotspot loop using the -S option of gcc and clang, and found that > 64-bit arithmetic is expanded inline with 32-bit instructions on > ARM32, HPPA, and M68K, none of which have 64-bit arithmetic > instructions. The loop instruction counts are comparable across all > of those systems, typically 10 to 20 instructions, compared to 5 or so > on those CPUs that have 64-bit arithmetic. > > The dramatic slowdowns on HPPA and SPARC64 are a big surprise, but the > HPPA slowdown matches the poor interactive response. The SPARC64 VM > is much more responsive interactively, and it DOES have 64-bit integer > arithmetic. > > I have not yet done profiling builds of qemu-system-hppa and > qemu-system-sparc64, but that remains an option for further > investigation to find out what is responsible for the slowness. > > I can also do profiling builds of parts of my test suite to see > whether there are unexpected hotspots on HPPA and SPARC64 that are > absent on other CPU types. > > I have physical SPARC64 hardware running Debian 11 and Solaris 10 on > identical boxes, and have done builds of TeX Live on them with no > difficulty. However, the slow speed of QEMU HPPA makes it impractical > to try TeX Live builds for Debian 11 HPPA, which is disappointing. > > Does any list member have any idea of why QEMU emulation of HPPA and > SPARC64 is so bad? Are there Debian kernel parameters that might be > tweaked? Have any of you used Debian on QEMU HPPA and seen similar > slowness compared to other CPU types? > > Notice from my first table above that NetBSD 9.2 on HPPA is also very > slow, which tends to point the finger at QEMU as the source of the > dismal performance, rather than the VM guest O/S. > > For the record, here is how QEMU releases downloaded from > > https://www.qemu.org/ > https://download.qemu.org/ > > are built here, taking the most recent QEMU release for the sample: > > tar xf $prefix/src/qemu/qemu-6.1.0-rc3.tar.xz > cd qemu-6.1.0-rc3 > unsetenv CONFIG_SITE > mkdir build > cd build > env CC=cc CFLAGS=-O2 ../configure --prefix=$prefix && make all -j && > make check > > QEMU builds require prior installation of the ninja-build package > available on major GNU/Linux distributions. On completion, the needed > qemu-system-xxx executables are present in the build subdirectory. > > On Ubuntu 20.04, the QEMU builds are clean, and pass the entire > validation suite without any failures. > > ------------------------------------------------------------------------------- > - Nelson H. F. Beebe Tel: +1 801 581 5254 > - > - University of Utah FAX: +1 801 581 4148 > - > - Department of Mathematics, 110 LCB Internet e-mail: be...@math.utah.edu > - > - 155 S 1400 E RM 233 be...@acm.org be...@computer.org > - > - Salt Lake City, UT 84112-0090, USA URL: http://www.math.utah.edu/~beebe/ > - > ------------------------------------------------------------------------------- > -- John David Anglin dave.ang...@bell.net
