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Messages - DKnoto

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…Some even chastising me for my choice in hardware lol
It seems that people for the sake of convenience are able to sacrifice everything ;)

Operating Systems and Porting / Re: [NEWS] Fedora 37 has arrived!
« on: March 13, 2023, 05:29:14 am »
I have had the same problem for a few days and came to the same conclusion, I am waiting  ;)

Talos II / Re: Unsatisfactory performance of SSD drives
« on: February 26, 2023, 08:00:12 am »
After two months of testing, I can present how the performance of my SSD changed
depending on the kernel version. I didn't expect there to be so much variability.
The results in the form of a graph in the attached image ;)

No, full monitor resolution 1600x1200 works fine.

Today I had a day off and decided to install Fedora Rawhide from 2022/12./23, which I had downloaded two days earlier,
on a trial basis. The installation from the usb key went without any major problems, remembering my previous problems
with XFS this time I chose ext2 for the /boot directory and ext4 for the rest.

After the installation I was positively surprised, GDM booted by default with Wayland enabled and ran desktop on both cards:
ASPEED and Radeon Pro WX7100. I have two monitors connected to the Radeon with resolutions of 5120x2160 and 1920x1200.
To the ASPEED card I have a monitor connected with a resolution of 1600x1200. Wayland ran at maximum resolution on the two
smaller monitors and at 2560x1080 on the largest monitor. Gnome 43.1 ran quite smoothly on this virtual screen. Even moving
windows from tab to tab caused no noticeable problems. I tried to increase the resolution on the largest monitor from within Gnome
but was unsuccessful. Unfortunately, due to Wayland's serious shortcomings when it comes to the ability to configure details,
gnome-tweaks, xset, etc., I went back to the standard X11 installation with two monitors.

From my point of view, the most interesting new features in Fedora 38 are:
  • kernel 6.2.0 series, in this case 0.rc2.20230103;
  • very good support for Samsung SSDs, reding above 6.2 GB/s;
  • Gnome 43.1, which, despite the developers' efforts, can be personalized with extensions such as WhiteSur ;-)
  • NetBeans 16 and Java 17 work flawlessly.

Operating Systems and Porting / Re: [NEWS] Fedora 37 has arrived!
« on: December 20, 2022, 04:43:43 am »
This script gets the Petitboot version number from a file like this:
Code: [Select]
cat /sys/firmware/devicetree/base/ibm,firmware-versions/petitboot
and expects this string to be of the form, for example, 1.8.0 and gets something like this:
Code: [Select]
cat /sys/firmware/devicetree/base/ibm,firmware-versions/petitboot

Operating Systems and Porting / Re: [NEWS] Fedora 37 has arrived!
« on: December 19, 2022, 10:35:17 am »
In order for petitboot to see the new kernels you must run the following commands after the update:

Code: [Select]
$ sudo grub2-mkconfig > /boot/grub2/grub.cfg

This situation is due to an error in the /usr/lib/kernel.d/99-grub-mkconfig.install script on lines 28 and 29.
The script expects the Pettitboot version in Num1.Num2.Num3 format and reads the values in CRC1-CRC2 format.

Talos II / Re: Unsatisfactory performance of SSD drives
« on: December 01, 2022, 07:22:41 am »
Good news, Fedora 36 has experienced an amazing progression in this subject over the past month.

Kernel 6.0.9: ~30% increase in read performance over the 6.0.5 version.

Kernel 6.0.10: ~425% increase in read performance over the 6.0.9 version :)

Talos II / Re: Unsatisfactory performance of SSD drives
« on: November 08, 2022, 12:34:13 pm »
Code: [Select]

# lspci -s 0001:01:00.0 -vv

0001:01:00.0 Non-Volatile memory controller: Samsung Electronics Co Ltd NVMe SSD Controller PM9A1/PM9A3/980PRO (prog-if 02 [NVM Express])
Subsystem: Samsung Electronics Co Ltd Device a801
Device tree node: /sys/firmware/devicetree/base/pciex@600c3c0100000/pci@0/mass-storage@0
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr+ Stepping- SERR+ FastB2B- DisINTx+
Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 0
Interrupt: pin A routed to IRQ 33
NUMA node: 0
IOMMU group: 1
Region 0: Memory at 600c080000000 (64-bit, non-prefetchable) [size=16K]
Capabilities: [40] Power Management version 3
Flags: PMEClk- DSI- D1- D2- AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
Status: D0 NoSoftRst+ PME-Enable- DSel=0 DScale=0 PME-
Capabilities: [50] MSI: Enable- Count=1/32 Maskable- 64bit+
Address: 0000000000000000  Data: 0000
Capabilities: [70] Express (v2) Endpoint, MSI 00
DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s unlimited, L1 unlimited
ExtTag+ AttnBtn- AttnInd- PwrInd- RBE+ FLReset+ SlotPowerLimit 0.000W
DevCtl: CorrErr- NonFatalErr- FatalErr- UnsupReq-
RlxdOrd+ ExtTag+ PhantFunc- AuxPwr- NoSnoop+ FLReset-
MaxPayload 256 bytes, MaxReadReq 512 bytes
DevSta: CorrErr+ NonFatalErr- FatalErr- UnsupReq- AuxPwr- TransPend-
LnkCap: Port #0, Speed 16GT/s, Width x4, ASPM L1, Exit Latency L1 <64us
ClockPM+ Surprise- LLActRep- BwNot- ASPMOptComp+
LnkCtl: ASPM Disabled; RCB 64 bytes, Disabled- CommClk-
ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
LnkSta: Speed 16GT/s (ok), Width x4 (ok)
TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
DevCap2: Completion Timeout: Range ABCD, TimeoutDis+ NROPrPrP- LTR+
10BitTagComp+ 10BitTagReq- OBFF Not Supported, ExtFmt- EETLPPrefix-
EmergencyPowerReduction Not Supported, EmergencyPowerReductionInit-
FRS- TPHComp- ExtTPHComp-
AtomicOpsCap: 32bit- 64bit- 128bitCAS-
DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis+ LTR- OBFF Disabled,
AtomicOpsCtl: ReqEn-
LnkCap2: Supported Link Speeds: 2.5-16GT/s, Crosslink- Retimer+ 2Retimers+ DRS-
LnkCtl2: Target Link Speed: 16GT/s, EnterCompliance- SpeedDis-
Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
Compliance De-emphasis: -6dB
LnkSta2: Current De-emphasis Level: -6dB, EqualizationComplete+ EqualizationPhase1+
EqualizationPhase2+ EqualizationPhase3+ LinkEqualizationRequest-
Retimer- 2Retimers- CrosslinkRes: Upstream Port
Capabilities: [b0] MSI-X: Enable+ Count=130 Masked-
Vector table: BAR=0 offset=00003000
PBA: BAR=0 offset=00002000
Capabilities: [100 v2] Advanced Error Reporting
UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
CESta: RxErr+ BadTLP+ BadDLLP+ Rollover- Timeout+ AdvNonFatalErr-
CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- AdvNonFatalErr+
AERCap: First Error Pointer: 00, ECRCGenCap+ ECRCGenEn+ ECRCChkCap+ ECRCChkEn+
MultHdrRecCap+ MultHdrRecEn- TLPPfxPres- HdrLogCap-
HeaderLog: 00000000 00000000 00000000 00000000
Capabilities: [168 v1] Alternative Routing-ID Interpretation (ARI)
ARICap: MFVC- ACS-, Next Function: 0
ARICtl: MFVC- ACS-, Function Group: 0
Capabilities: [178 v1] Secondary PCI Express
LnkCtl3: LnkEquIntrruptEn- PerformEqu-
LaneErrStat: 0
Capabilities: [198 v1] Physical Layer 16.0 GT/s <?>
Capabilities: [1bc v1] Lane Margining at the Receiver <?>
Capabilities: [214 v1] Latency Tolerance Reporting
Max snoop latency: 0ns
Max no snoop latency: 0ns
Capabilities: [21c v1] L1 PM Substates
L1SubCap: PCI-PM_L1.2+ PCI-PM_L1.1+ ASPM_L1.2+ ASPM_L1.1+ L1_PM_Substates+
  PortCommonModeRestoreTime=10us PortTPowerOnTime=10us
L1SubCtl1: PCI-PM_L1.2- PCI-PM_L1.1- ASPM_L1.2- ASPM_L1.1-
   T_CommonMode=0us LTR1.2_Threshold=0ns
L1SubCtl2: T_PwrOn=10us
Capabilities: [3a0 v1] Data Link Feature <?>
Kernel driver in use: nvme
Kernel modules: nvme

hdparm gives better results but it is a single reading:

Code: [Select]
# hdparm -t /dev/nvme0n1

 Timing buffered disk reads: 12676 MB in  3.00 seconds = 4225.32 MB/sec

The workaround is trivial:
Code: [Select]
typedef signed char byte;


I checked it out at Actually in the example it says that these are "possible values". Nevertheless, I am very surprised that C++ defines its portability so poorly.

The same algorithm implemented in Java works equally on both platforms.

The test code:

Code: [Select]
import java.lang.*;

public class JLimits
    public static void main(String[] args)
        System.out.printf("byte.MAX_VALUE == %d.\n", Byte.MAX_VALUE);

Thanks for the hint, I am implementing a workaround.

On FreeBSD 14.0 ppc64 with clang 14.0.5 has the same thing.

Applications and Porting / Problem with std::numeric_limits<char>::max()
« on: November 03, 2022, 02:37:51 pm »
I'm porting my software to ppc64le and ran into a problem in the std::numeric_limits<char>::max() function. According to
the documentation, this operation should return the value CHAR_MAX which is 127. This is the case on x86_64 with gcc 11.3.1
compiler. Unfortunately on ppc64le the code compiled with gcc 12.2.1 returns the value UCHAR_MAX which is 255.

Test code:
Code: [Select]
printf("std::numeric_limits<char>::max() == %d\n", static_cast<int>(std::numeric_limits<char>::max()));

Clang 14.0.5 and IBM xlc 16.01.0001.0003 return the same value.

Have any of you encountered such a problem on distributions other than Fedora 36?


Operating Systems and Porting / Re: Trying out Chimera Linux
« on: November 03, 2022, 04:03:11 am »
I haven't used KDE in a long time, about 15 years ;-) I installed KDE on Talos II but I wasn't satisfied,
the graphics handling is somehow weird. When resizing the window, rendering runs terribly slow. But
I will try to play with it again. Configuring KDE to a usable state, I want KDE to look like my macOS
on my laptop, is tedious.

Talos II / Unsatisfactory performance of SSD drives
« on: November 01, 2022, 08:57:16 am »
I switched to the Talos II machine from a Dell Precision 7730 laptop. In the laptop I had an older-generation Samsung SSD,
a 970 Pro, connected via an M.2 connector to PCI 3.0. In the Talos II I used a 980 Pro connected to PCI 4.0 via an ICY BOX
PCIe 4.0 x4 - M.2 PCIe NVMe controller (up to 64 Gbit/s). I expected a read transfer of 5-6 GB/s and got 0.9 GB/s.
That's more than three times slower than on a laptop. Screenshots attached.

Is there any way to improve this?

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