On 9/2/2023 10:56, Brian Inglis wrote:
On 2023-09-02 08:57, jeff via Cygwin wrote:
I have a program that is embarrassing parallel.
On my older computer which has an epyc 7302 (16 cores, 32 threads)
it scales very well using cygwin, and fully utilized all threads.
On my new computer which has an epyc 7B13 (64 cores, 128 threads) it
does not scale very well.
According to the windows task manager, it only uses 74% of the cpu
resources.
The time it takes the program to run on windows is 166 seconds.
Using the same hardware on a recent version of linux, I can get 100%
cpu utilization and the program takes 100 seconds to run.
I suspect there may be something in cygwin that doesn't scale well
with lots of posix threads.
I know this is a bit of an unusual situation, but you can buy a 128
core / 256 thread system now.
Enclosed is the output of cygcheck.
I updated my version of cygwin to be current as of today, Sep 2 2023.
What Windows edition and version are you running?
For details run:
$ reg query "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows
NT\CurrentVersion" \
| sed '/^\s\+\.*\s/!d;/^.\{80,\}/d'
Some retail editions limit you to 64 threads and that seems to be your
case:
NUMBER_OF_PROCESSORS = '64'
To make full use of your processors, you may have to upgrade your
Windows to a commercial licence (and installation) of Windows 10/11
Pro for Workstations, enabling server features on non-server
"Worskations" ~ HEDTs (High-End DeskTops); see:
https://www.anandtech.com/show/15483/amd-threadripper-3990x-review/3
or just run Linux!
Watch out for terms misused like processor == socket on some sites!
Also, you have to consider these are server systems, mainly designed
for VM not HPC (High Performance Computing) parallelism.
Your older system has higher base and boost/turbo clocks 3.0-3.3GHz:
your newer system has lower clocks 2.25-2.65/3/3.5GHz which seems to
depend on OEM target.
You may also need to upgrade your memory, as each core could run
~10GB/s instructions, and these workstations are often provisioned
with 128-256GB (2-4GB/core), so that may also need a Windows edition
upgrade.
I am running windows 10 professional. Using the task manager, 64 cores
and 128 threads shows up for my processor.
Here is the output of your regex:
SystemRoot REG_SZ C:\Windows
BaseBuildRevisionNumber REG_DWORD 0x1
BuildBranch REG_SZ vb_release
BuildGUID REG_SZ ffffffff-ffff-ffff-ffff-ffffffffffff
BuildLab REG_SZ 19041.vb_release.191206-1406
BuildLabEx REG_SZ 19041.1.amd64fre.vb_release.191206-1406
CompositionEditionID REG_SZ Enterprise
CurrentBuild REG_SZ 19045
CurrentBuildNumber REG_SZ 19045
CurrentMajorVersionNumber REG_DWORD 0xa
CurrentMinorVersionNumber REG_DWORD 0x0
CurrentType REG_SZ Multiprocessor Free
CurrentVersion REG_SZ 6.3
EditionID REG_SZ Professional
EditionSubManufacturer REG_SZ
EditionSubstring REG_SZ
EditionSubVersion REG_SZ
InstallationType REG_SZ Client
InstallDate REG_DWORD 0x61e2300a
ProductName REG_SZ Windows 10 Pro
ReleaseId REG_SZ 2009
SoftwareType REG_SZ System
UBR REG_DWORD 0xcfc
PathName REG_SZ C:\Windows
ProductId REG_SZ 00330-80000-00000-AA073
DisplayVersion REG_SZ 22H2
RegisteredOwner REG_SZ jdeifik
RegisteredOrganization REG_SZ
InstallTime REG_QWORD 0x1d809b6d4ce7b09
In practice, but the new and old processors typically run at about 3ghz
when under load.
When idling, both processors use about the same amount of power.
I have 128gb of ram, in 4 slots. Using that configuration, I can get
100% load and significant faster performance on linux.
Therefore I conclude the issue is either with windows or cygwin, and is
not a hardware issue.
When I run cinebench, I can get to 100% cpu utulization (at around 3ghz)
on windows.
As for what the processors are 'designed' for, I really don't care.
I want a reliable, fast computer with ECC memory, and I can get that
with an EPYC processor.
If a workload needs more than 128gb of memory, you pretty much need to
use server processors.
I can put in up to 2tb of memory in my system, if I have the need for that.
jeff
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