nvme pcie gen4 + linux \ низкая скорость записи\чтения

dd if=/dev/zero of=test bs=1G count=1 oflag=direct
1+0 записей получено
1+0 записей отправлено
1073741824 байт (1,1 GB, 1,0 GiB) скопирован, 0,948863 s, 1,1 GB/s

dd if=/dev/zero of=test bs=512 count=1000 oflag=direct
1000+0 записей получено
1000+0 записей отправлено
512000 байт (512 kB, 500 KiB) скопирован, 0,0678338 s, 7,5 MB/s

dd if=/dev/zero of=test bs=1G count=1 oflag=sync
1+0 записей получено
1+0 записей отправлено
1073741824 байт (1,1 GB, 1,0 GiB) скопирован, 1,4448 s, 743 MB/s

dd так себе тест (плюс вы вызываете его неправильно), лучше fio использовать.

# fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=test --bs=4k --iodepth=64 --size=4G --readwrite=randwrite
test: (g=0): rw=randwrite, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=libaio, iodepth=64
fio-3.14
Starting 1 process
test: Laying out IO file (1 file / 4096MiB)
Jobs: 1 (f=1): [w(1)][100.0%][w=656MiB/s][w=168k IOPS][eta 00m:00s]
test: (groupid=0, jobs=1): err= 0: pid=6002: Sat Jun 13 12:17:20 2020
  write: IOPS=162k, BW=632MiB/s (663MB/s)(4096MiB/6482msec); 0 zone resets
   bw (  KiB/s): min=591264, max=687200, per=98.86%, avg=639692.00, stdev=26037.46, samples=12
   iops        : min=147816, max=171800, avg=159923.00, stdev=6509.36, samples=12
  cpu          : usr=12.73%, sys=86.68%, ctx=3393, majf=0, minf=7
  IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=0.1%, >=64=100.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.1%, >=64=0.0%
     issued rwts: total=0,1048576,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=64

Run status group 0 (all jobs):
  WRITE: bw=632MiB/s (663MB/s), 632MiB/s-632MiB/s (663MB/s-663MB/s), io=4096MiB (4295MB), run=6482-6482msec

Disk stats (read/write):
    dm-2: ios=0/1033494, merge=0/0, ticks=0/20689, in_queue=20689, util=98.51%, aggrios=0/1048792, aggrmerge=0/2649, aggrticks=0/21707, aggrin_queue=0, aggrutil=97.99%
  nvme0n1: ios=0/1048792, merge=0/2649, ticks=0/21707, in_queue=0, util=97.99%

# fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=test --bs=4k --iodepth=64 --size=4G --readwrite=randread
test: (g=0): rw=randread, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=libaio, iodepth=64
fio-3.14
Starting 1 process
Jobs: 1 (f=1): [r(1)][-.-%][r=1252MiB/s][r=321k IOPS][eta 00m:00s]
test: (groupid=0, jobs=1): err= 0: pid=6083: Sat Jun 13 12:19:25 2020
  read: IOPS=317k, BW=1237MiB/s (1297MB/s)(4096MiB/3311msec)
   bw (  MiB/s): min= 1178, max= 1270, per=99.88%, avg=1235.58, stdev=38.12, samples=6
   iops        : min=301808, max=325364, avg=316308.67, stdev=9759.70, samples=6
  cpu          : usr=13.87%, sys=52.57%, ctx=72203, majf=0, minf=72
  IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=0.1%, >=64=100.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.1%, >=64=0.0%
     issued rwts: total=1048576,0,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=64

Run status group 0 (all jobs):
   READ: bw=1237MiB/s (1297MB/s), 1237MiB/s-1237MiB/s (1297MB/s-1297MB/s), io=4096MiB (4295MB), run=3311-3311msec

Disk stats (read/write):
    dm-2: ios=997009/37, merge=0/0, ticks=190066/0, in_queue=190066, util=96.86%, aggrios=1048576/29, aggrmerge=0/8, aggrticks=200473/2, aggrin_queue=283, aggrutil=96.25%
  nvme0n1: ios=1048576/29, merge=0/8, ticks=200473/2, in_queue=283, util=96.25%

# fio --randrepeat=1 --ioengine=libaio --direct=1 --gtod_reduce=1 --name=test --filename=test --bs=4k --iodepth=64 --size=4G --readwrite=randrw --rwmixread=75
test: (g=0): rw=randrw, bs=(R) 4096B-4096B, (W) 4096B-4096B, (T) 4096B-4096B, ioengine=libaio, iodepth=64
fio-3.14
Starting 1 process
Jobs: 1 (f=1): [m(1)][-.-%][r=1090MiB/s,w=363MiB/s][r=279k,w=92.0k IOPS][eta 00m:00s]
test: (groupid=0, jobs=1): err= 0: pid=6107: Sat Jun 13 12:20:17 2020
  read: IOPS=268k, BW=1047MiB/s (1098MB/s)(3070MiB/2931msec)
   bw (  MiB/s): min=  941, max= 1102, per=99.48%, avg=1041.95, stdev=72.26, samples=5
   iops        : min=241114, max=282210, avg=266739.60, stdev=18498.73, samples=5
  write: IOPS=89.6k, BW=350MiB/s (367MB/s)(1026MiB/2931msec); 0 zone resets
   bw (  KiB/s): min=321368, max=376424, per=99.71%, avg=357408.00, stdev=25469.34, samples=5
   iops        : min=80342, max=94106, avg=89352.00, stdev=6367.34, samples=5
  cpu          : usr=16.86%, sys=65.90%, ctx=92725, majf=0, minf=7
  IO depths    : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=0.1%, >=64=100.0%
     submit    : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0%
     complete  : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.1%, >=64=0.0%
     issued rwts: total=785920,262656,0,0 short=0,0,0,0 dropped=0,0,0,0
     latency   : target=0, window=0, percentile=100.00%, depth=64

Run status group 0 (all jobs):
   READ: bw=1047MiB/s (1098MB/s), 1047MiB/s-1047MiB/s (1098MB/s-1098MB/s), io=3070MiB (3219MB), run=2931-2931msec
  WRITE: bw=350MiB/s (367MB/s), 350MiB/s-350MiB/s (367MB/s-367MB/s), io=1026MiB (1076MB), run=2931-2931msec

Disk stats (read/write):
    dm-2: ios=777634/259859, merge=0/0, ticks=141066/2991, in_queue=144057, util=96.43%, aggrios=785920/262657, aggrmerge=0/0, aggrticks=142710/3516, aggrin_queue=1095, aggrutil=95.37%
  nvme0n1: ios=785920/262657, merge=0/0, ticks=142710/3516, in_queue=1095, util=95.37%

# smartctl -a /dev/nvme0n1
smartctl 7.1 2019-12-30 r5022 [x86_64-linux-5.6.16-200.fc31.x86_64] (local build)
Copyright (C) 2002-19, Bruce Allen, Christian Franke, www.smartmontools.org

=== START OF INFORMATION SECTION ===
Model Number:                       Seagate FireCuda 520 SSD ZP1000GM30002
Serial Number:                      7QG006NS
Firmware Version:                   STNSC014
PCI Vendor/Subsystem ID:            0x1bb1
IEEE OUI Identifier:                0x0024cf
Total NVM Capacity:                 1 000 204 886 016 [1,00 TB]
Unallocated NVM Capacity:           0
Controller ID:                      1
Number of Namespaces:               1
Namespace 1 Size/Capacity:          1 000 204 886 016 [1,00 TB]
Namespace 1 Formatted LBA Size:     512
Namespace 1 IEEE EUI-64:            0024cf 0150001e1e
Local Time is:                      Sat Jun 13 12:22:56 2020 MSK
Firmware Updates (0x1e):            7 Slots, no Reset required
Optional Admin Commands (0x0017):   Security Format Frmw_DL Self_Test
Optional NVM Commands (0x005d):     Comp DS_Mngmt Wr_Zero Sav/Sel_Feat Timestmp
Maximum Data Transfer Size:         512 Pages
Warning  Comp. Temp. Threshold:     90 Celsius
Critical Comp. Temp. Threshold:     95 Celsius

Supported Power States
St Op     Max   Active     Idle   RL RT WL WT  Ent_Lat  Ex_Lat
 0 +     9.78W       -        -    0  0  0  0        0       0
 1 +     6.75W       -        -    1  1  1  1        0       0
 2 +     5.23W       -        -    2  2  2  2        0       0
 3 -   0.0490W       -        -    3  3  3  3     2000    2000
 4 -   0.0018W       -        -    4  4  4  4    25000   25000

Supported LBA Sizes (NSID 0x1)
Id Fmt  Data  Metadt  Rel_Perf
 0 +     512       0         2
 1 -    4096       0         1

=== START OF SMART DATA SECTION ===
SMART overall-health self-assessment test result: PASSED

SMART/Health Information (NVMe Log 0x02)
Critical Warning:                   0x00
Temperature:                        42 Celsius
Available Spare:                    100%
Available Spare Threshold:          5%
Percentage Used:                    0%
Data Units Read:                    549 088 [281 GB]
Data Units Written:                 1 395 647 [714 GB]
Host Read Commands:                 4 136 575
Host Write Commands:                3 209 976
Controller Busy Time:               11
Power Cycles:                       59
Power On Hours:                     25
Unsafe Shutdowns:                   47
Media and Data Integrity Errors:    0
Error Information Log Entries:      29
Warning  Comp. Temperature Time:    0
Critical Comp. Temperature Time:    0

Error Information (NVMe Log 0x01, max 63 entries)
No Errors Logged