This is current/amd64 on a PC (dmesg below).
It is using this M2 SSD as a system disk:
sd0 at scsibus1 targ 0 lun 0: <ATA, WDC WDS250G2B0B, 4010> naa.5001b448b8532530
sd0: 238475MB, 512 bytes/sector, 488397168 sectors, thin
I do a weekly dd read of all disks as a precaution
to see if any of the report any errors, as in
dd bs=1m conv=noerror if=/dev/rsd0c of=/dev/null
This particular disk seems to be very fast when reading
up to something between 3GB and 4GB; then the speed drops:
dd bs=1m count=1k conv=noerror if=/dev/rsd0c of=/dev/null
1073741824 bytes transferred in 5.404 secs (198679263 bytes/sec)
1073741824 bytes transferred in 5.271 secs (203672530 bytes/sec)
1073741824 bytes transferred in 5.072 secs (211697503 bytes/sec)
dd bs=1m count=2k conv=noerror if=/dev/rsd0c of=/dev/null
2147483648 bytes transferred in 8.392 secs (255879364 bytes/sec)
2147483648 bytes transferred in 8.413 secs (255242225 bytes/sec)
2147483648 bytes transferred in 9.139 secs (234968292 bytes/sec)
dd bs=1m count=3k conv=noerror if=/dev/rsd0c of=/dev/null
3221225472 bytes transferred in 11.823 secs (272447923 bytes/sec)
3221225472 bytes transferred in 12.124 secs (265674803 bytes/sec)
dd bs=1m count=4k conv=noerror if=/dev/rsd0c of=/dev/null
4294967296 bytes transferred in 53.442 secs (80365818 bytes/sec)
4294967296 bytes transferred in 52.680 secs (81528574 bytes/sec)
4294967296 bytes transferred in 52.082 secs (82465212 bytes/sec)
dd bs=1m count=5k conv=noerror if=/dev/rsd0c of=/dev/null
5368709120 bytes transferred in 179.967 secs (29831567 bytes/sec)
5368709120 bytes transferred in 221.400 secs (24248900 bytes/sec)
5368709120 bytes transferred in 215.760 secs (24882667 bytes/sec)
That's a drop from 200MB/s to 20MB/s.
I get a similar rate of slowdown with different dd bs.
Is this expected when doing a long sequential read of this kind of disks?
(The rotating disks also slow down when doing a long read,
but only marginaly: a dd read of the whole disk is not
that much slower than a read of the first 10GB.)
Jan
OpenBSD 7.1-current (GENERIC.MP) #0: Thu Apr 14 13:26:20 CEST 2022
h...@box.stare.cz:/usr/src/sys/arch/amd64/compile/GENERIC.MP
real mem = 17009606656 (16221MB)
avail mem = 16476803072 (15713MB)
random: good seed from bootblocks
mpath0 at root
scsibus0 at mpath0: 256 targets
mainbus0 at root
bios0 at mainbus0: SMBIOS rev. 2.4 @ 0xf0100 (36 entries)
bios0: vendor Award Software International, Inc. version "F3" date 03/31/2011
bios0: Gigabyte Technology Co., Ltd. H67MA-USB3-B3
acpi0 at bios0: ACPI 1.0
acpi0: sleep states S0 S3 S4 S5
acpi0: tables DSDT FACP HPET MCFG ASPT SSPT EUDS MATS TAMG APIC SSDT
acpi0: wakeup devices PCI0(S5) PEX0(S5) PEX1(S5) PEX2(S5) PEX3(S5) PEX4(S5)
PEX5(S5) PEX6(S5) PEX7(S5) HUB0(S5) UAR1(S3) USBE(S3) USE2(S3) AZAL(S5)
acpitimer0 at acpi0: 3579545 Hz, 24 bits
acpihpet0 at acpi0: 14318179 Hz
acpimcfg0 at acpi0
acpimcfg0: addr 0xf4000000, bus 0-63
acpimadt0 at acpi0 addr 0xfee00000: PC-AT compat
cpu0 at mainbus0: apid 0 (boot processor)
cpu0: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz, 3492.60 MHz, 06-2a-07
cpu0:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,POPCNT,DEADLINE,AES,XSAVE,AVX,NXE,RDTSCP,LONG,LAHF,PERF,ITSC,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,MELTDOWN
cpu0: 256KB 64b/line 8-way L2 cache
cpu0: smt 0, core 0, package 0
mtrr: Pentium Pro MTRR support, 10 var ranges, 88 fixed ranges
cpu0: apic clock running at 99MHz
cpu0: mwait min=64, max=64, C-substates=0.2.1.1, IBE
cpu1 at mainbus0: apid 2 (application processor)
cpu1: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz, 3492.10 MHz, 06-2a-07
cpu1:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,POPCNT,DEADLINE,AES,XSAVE,AVX,NXE,RDTSCP,LONG,LAHF,PERF,ITSC,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,MELTDOWN
cpu1: 256KB 64b/line 8-way L2 cache
cpu1: smt 0, core 1, package 0
cpu2 at mainbus0: apid 4 (application processor)
cpu2: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz, 3492.09 MHz, 06-2a-07
cpu2:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,POPCNT,DEADLINE,AES,XSAVE,AVX,NXE,RDTSCP,LONG,LAHF,PERF,ITSC,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,MELTDOWN
cpu2: 256KB 64b/line 8-way L2 cache
cpu2: smt 0, core 2, package 0
cpu3 at mainbus0: apid 6 (application processor)
cpu3: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz, 3492.09 MHz, 06-2a-07
cpu3:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,POPCNT,DEADLINE,AES,XSAVE,AVX,NXE,RDTSCP,LONG,LAHF,PERF,ITSC,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,MELTDOWN
cpu3: 256KB 64b/line 8-way L2 cache
cpu3: smt 0, core 3, package 0
cpu4 at mainbus0: apid 1 (application processor)
cpu4: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz, 3492.08 MHz, 06-2a-07
cpu4:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,POPCNT,DEADLINE,AES,XSAVE,AVX,NXE,RDTSCP,LONG,LAHF,PERF,ITSC,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,MELTDOWN
cpu4: 256KB 64b/line 8-way L2 cache
cpu4: smt 1, core 0, package 0
cpu5 at mainbus0: apid 3 (application processor)
cpu5: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz, 3492.09 MHz, 06-2a-07
cpu5:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,POPCNT,DEADLINE,AES,XSAVE,AVX,NXE,RDTSCP,LONG,LAHF,PERF,ITSC,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,MELTDOWN
cpu5: 256KB 64b/line 8-way L2 cache
cpu5: smt 1, core 1, package 0
cpu6 at mainbus0: apid 5 (application processor)
cpu6: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz, 3492.08 MHz, 06-2a-07
cpu6:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,POPCNT,DEADLINE,AES,XSAVE,AVX,NXE,RDTSCP,LONG,LAHF,PERF,ITSC,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,MELTDOWN
cpu6: 256KB 64b/line 8-way L2 cache
cpu6: smt 1, core 2, package 0
cpu7 at mainbus0: apid 7 (application processor)
cpu7: Intel(R) Core(TM) i7-2600 CPU @ 3.40GHz, 3492.09 MHz, 06-2a-07
cpu7:
FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CFLUSH,DS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE,SSE3,PCLMUL,DTES64,MWAIT,DS-CPL,VMX,SMX,EST,TM2,SSSE3,CX16,xTPR,PDCM,PCID,SSE4.1,SSE4.2,x2APIC,POPCNT,DEADLINE,AES,XSAVE,AVX,NXE,RDTSCP,LONG,LAHF,PERF,ITSC,MD_CLEAR,IBRS,IBPB,STIBP,L1DF,SSBD,SENSOR,ARAT,XSAVEOPT,MELTDOWN
cpu7: 256KB 64b/line 8-way L2 cache
cpu7: smt 1, core 3, package 0
ioapic0 at mainbus0: apid 2 pa 0xfec00000, version 20, 24 pins, remapped
acpiprt0 at acpi0: bus 0 (PCI0)
acpiprt1 at acpi0: bus -1 (PEG0)
acpiprt2 at acpi0: bus -1 (PEG1)
acpiprt3 at acpi0: bus 1 (PEX0)
acpiprt4 at acpi0: bus -1 (PEX1)
acpiprt5 at acpi0: bus -1 (PEX2)
acpiprt6 at acpi0: bus -1 (PEX3)
acpiprt7 at acpi0: bus 2 (PEX4)
acpiprt8 at acpi0: bus -1 (PEX5)
acpiprt9 at acpi0: bus 4 (PEX6)
acpiprt10 at acpi0: bus 5 (PEX7)
acpibtn0 at acpi0: PWRB
acpipci0 at acpi0 PCI0
acpicmos0 at acpi0
com0 at acpi0 UAR1 addr 0x3f8/0x8 irq 4: ns16550a, 16 byte fifo
acpicpu0 at acpi0: C3(350@96 mwait.1@0x20), C2(500@64 mwait.1@0x10), C1(1000@1
mwait.1), PSS
acpicpu1 at acpi0: C3(350@96 mwait.1@0x20), C2(500@64 mwait.1@0x10), C1(1000@1
mwait.1), PSS
acpicpu2 at acpi0: C3(350@96 mwait.1@0x20), C2(500@64 mwait.1@0x10), C1(1000@1
mwait.1), PSS
acpicpu3 at acpi0: C3(350@96 mwait.1@0x20), C2(500@64 mwait.1@0x10), C1(1000@1
mwait.1), PSS
acpicpu4 at acpi0: C3(350@96 mwait.1@0x20), C2(500@64 mwait.1@0x10), C1(1000@1
mwait.1), PSS
acpicpu5 at acpi0: C3(350@96 mwait.1@0x20), C2(500@64 mwait.1@0x10), C1(1000@1
mwait.1), PSS
acpicpu6 at acpi0: C3(350@96 mwait.1@0x20), C2(500@64 mwait.1@0x10), C1(1000@1
mwait.1), PSS
acpicpu7 at acpi0: C3(350@96 mwait.1@0x20), C2(500@64 mwait.1@0x10), C1(1000@1
mwait.1), PSS
cpu0: using VERW MDS workaround (except on vmm entry)
cpu0: Enhanced SpeedStep 3492 MHz: speeds: 3701, 3700, 3600, 3500, 3400, 3300,
3200, 3100, 3000, 2900, 2800, 2700, 2600, 2500, 2400, 2300, 2200, 2100, 1600 MHz
pci0 at mainbus0 bus 0
pchb0 at pci0 dev 0 function 0 "Intel Core 2G Host" rev 0x09
inteldrm0 at pci0 dev 2 function 0 "Intel HD Graphics 2000" rev 0x09
drm0 at inteldrm0
inteldrm0: apic 2 int 16, SANDYBRIDGE, gen 6
"Intel 6 Series MEI" rev 0x04 at pci0 dev 22 function 0 not configured
ehci0 at pci0 dev 26 function 0 "Intel 6 Series USB" rev 0x05: apic 2 int 18
usb0 at ehci0: USB revision 2.0
uhub0 at usb0 configuration 1 interface 0 "Intel EHCI root hub" rev 2.00/1.00
addr 1
azalia0 at pci0 dev 27 function 0 "Intel 6 Series HD Audio" rev 0x05: apic 2
int 22
azalia0: codecs: Realtek ALC889, Intel/0x2805, using Realtek ALC889
audio0 at azalia0
ppb0 at pci0 dev 28 function 0 "Intel 6 Series PCIE" rev 0xb5: apic 2 int 16
pci1 at ppb0 bus 1
ppb1 at pci0 dev 28 function 4 "Intel 6 Series PCIE" rev 0xb5: apic 2 int 16
pci2 at ppb1 bus 2
ppb2 at pci2 dev 0 function 0 "TI XIO2000A PCIE-PCI" rev 0x03
pci3 at ppb2 bus 3
puc0 at pci3 dev 0 function 0 "NetMos Nm9835" rev 0x01: ports: 15 com, 1 lpt
com4 at puc0 port 0 apic 2 int 16: ns16550a, 16 byte fifo
com5 at puc0 port 1 apic 2 int 16: ns16550a, 16 byte fifo
lpt1 at puc0 port 2 apic 2 int 16
ppb3 at pci0 dev 28 function 6 "Intel 6 Series PCIE" rev 0xb5: apic 2 int 18
pci4 at ppb3 bus 4
re0 at pci4 dev 0 function 0 "Realtek 8168" rev 0x06: RTL8168E/8111E-VL
(0x2c80), apic 2 int 18, address 50:e5:49:36:ec:0d
rgephy0 at re0 phy 7: RTL8169S/8110S/8211 PHY, rev. 5
ppb4 at pci0 dev 28 function 7 "Intel 6 Series PCIE" rev 0xb5: apic 2 int 19
pci5 at ppb4 bus 5
xhci0 at pci5 dev 0 function 0 "Etron EJ168 xHCI" rev 0x01: apic 2 int 19, xHCI
1.0
usb1 at xhci0: USB revision 3.0
uhub1 at usb1 configuration 1 interface 0 "Etron xHCI root hub" rev 3.00/1.00
addr 1
ehci1 at pci0 dev 29 function 0 "Intel 6 Series USB" rev 0x05: apic 2 int 23
usb2 at ehci1: USB revision 2.0
uhub2 at usb2 configuration 1 interface 0 "Intel EHCI root hub" rev 2.00/1.00
addr 1
ppb5 at pci0 dev 30 function 0 "Intel 82801BA Hub-to-PCI" rev 0xa5
pci6 at ppb5 bus 6
pcib0 at pci0 dev 31 function 0 "Intel H67 LPC" rev 0x05
ahci0 at pci0 dev 31 function 2 "Intel 6 Series AHCI" rev 0x05: apic 2 int 19,
AHCI 1.3
ahci0: port 0: 6.0Gb/s
ahci0: port 1: 6.0Gb/s
ahci0: port 2: 3.0Gb/s
ahci0: port 4: 3.0Gb/s
scsibus1 at ahci0: 32 targets
sd0 at scsibus1 targ 0 lun 0: <ATA, WDC WDS250G2B0B, 4010> naa.5001b448b8532530
sd0: 238475MB, 512 bytes/sector, 488397168 sectors, thin
sd1 at scsibus1 targ 1 lun 0: <ATA, ST2000DM008-2FR1, 0001> naa.5000c500c128f41c
sd1: 1907729MB, 512 bytes/sector, 3907029168 sectors, thin
sd2 at scsibus1 targ 2 lun 0: <ATA, WDC WD30EZRX-00M, 80.0> naa.50014ee25c38d81f
sd2: 2861588MB, 512 bytes/sector, 5860533168 sectors
sd3 at scsibus1 targ 4 lun 0: <ATA, WDC WD30EFRX-68E, 82.0> naa.50014ee20aaed824
sd3: 2861588MB, 512 bytes/sector, 5860533168 sectors
ichiic0 at pci0 dev 31 function 3 "Intel 6 Series SMBus" rev 0x05: apic 2 int 18
iic0 at ichiic0
spdmem0 at iic0 addr 0x50: 4GB DDR3 SDRAM PC3-12800
spdmem1 at iic0 addr 0x51: 4GB DDR3 SDRAM PC3-12800
spdmem2 at iic0 addr 0x52: 4GB DDR3 SDRAM PC3-12800
spdmem3 at iic0 addr 0x53: 4GB DDR3 SDRAM PC3-12800
isa0 at pcib0
isadma0 at isa0
pckbc0 at isa0 port 0x60/5 irq 1 irq 12
pcppi0 at isa0 port 0x61
spkr0 at pcppi0
it0 at isa0 port 0x2e/2: IT8728F rev 1, EC port 0x290
vmm0 at mainbus0: VMX/EPT
uhub3 at uhub0 port 1 configuration 1 interface 0 "Intel Rate Matching Hub" rev
2.00/0.00 addr 2
uhidev0 at uhub3 port 1 configuration 1 interface 0 "Genius Optical Mouse" rev
1.10/1.00 addr 3
uhidev0: iclass 3/1
ums0 at uhidev0: 3 buttons, Z dir
wsmouse0 at ums0 mux 0
uhidev1 at uhub3 port 2 configuration 1 interface 0 "Logitech USB Keyboard" rev
1.10/64.00 addr 4
uhidev1: iclass 3/1
ukbd0 at uhidev1: 8 variable keys, 6 key codes
wskbd0 at ukbd0: console keyboard
uhidev2 at uhub3 port 2 configuration 1 interface 1 "Logitech USB Keyboard" rev
1.10/64.00 addr 4
uhidev2: iclass 3/0, 3 report ids
ucc0 at uhidev2 reportid 1: 2 usages, 3 keys, enum
wskbd1 at ucc0 mux 1
uhid0 at uhidev2 reportid 2: input=1, output=0, feature=0
ucc1 at uhidev2 reportid 3: 21 usages, 14 keys, enum
wskbd2 at ucc1 mux 1
uhub4 at uhub2 port 1 configuration 1 interface 0 "Intel Rate Matching Hub" rev
2.00/0.00 addr 2
vscsi0 at root
scsibus2 at vscsi0: 256 targets
softraid0 at root
scsibus3 at softraid0: 256 targets
root on sd0a (8e7aa56bfa6854a1.a) swap on sd0b dump on sd0b
inteldrm0: 1360x768, 32bpp
wsdisplay0 at inteldrm0 mux 1: console (std, vt100 emulation), using wskbd0
wskbd1: connecting to wsdisplay0
wskbd2: connecting to wsdisplay0
wsdisplay0: screen 1-5 added (std, vt100 emulation)
