[Kernel-packages] [Bug 1785020] Re: fsync is slow on later kernels with ext4 filesystms
Retested release candidate kernel, fsync issue seemed to have been
fixed.
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https://bugs.launchpad.net/bugs/1785020
Title:
fsync is slow on later kernels with ext4 filesystms
Status in linux package in Ubuntu:
Incomplete
Bug description:
So this is a simple one, if I run the following code (see below) on Ubuntu
18.04 (4.15.0-29-generic ) and against Ubuntu 16.04 ( 4.4.0-87-generic) I get
two different results ; The question is why? It seems that fsync may be broken
in the latest kernel and may well be broken as early as 4.10 ? This has huge
implications around performance sensitive applications like mysql.
It also so worth noting that I'm running this against an ext4 filesystem with
the following mount options
rw,noatime,nodiratime,nobarrier,data=journal
4.4.0-87-generic - # time ./fsync
real 0m7.537s <-
user 0m0.000s
sys 0m1.060s <-
4.15.0-29-generic - # time ./fsync
real 1m38.299s <-
user 0m0.013s
sys 0m0.893s <-
Linux buntu-1804 4.15.0-29-generic
no sync() seconds:0.024438 writes per second:0.00
sync() seconds:1.705764 writes per second:0.00
real3m6.475s
user0m0.006s
sys 0m1.725s
Linux ubuntu 4.4.0-87-generic
no sync() seconds:0.012887 writes per second:0.01
sync() seconds:0.736563 writes per second:0.00
real0m8.945s
user0m0.016s
sys 0m0.732s
#!/usr/bin/python
import os, sys, mmap
# Open a file
fd = os.open( "/a/testfile", os.O_RDWR|os.O_CREAT|os.O_DIRECT )
m = mmap.mmap(-1, 512)
for i in range (1,1):
os.lseek(fd,os.SEEK_SET,0)
m[1] = "1"
os.write(fd, m)
os.fsync(fd)
# Close opened file
os.close( fd )
#define _GNU_SOURCE
#include
#include
#include
#include
void withSync() {
int f = open( "/a/t8" , O_RDWR | O_CREAT |O_DIRECT );
lseek (f, 0, SEEK_SET );
int records = 10*1000;
clock_t ustart = clock();
for(int i = 0; i < records; i++) {
write(f, "012345678901234567890123456789" , 30);
fsync(f);
}
clock_t uend = clock();
close (f);
printf(" sync() seconds:%lf writes per second:%lf\n",
((double)(uend-ustart))/(CLOCKS_PER_SEC),
((double)records)/((double)(uend-ustart))/(CLOCKS_PER_SEC));
}
void withoutSync() {
int f = open( "/a/t10" , O_RDWR | O_CREAT | O_DIRECT );
lseek (f, 0, SEEK_SET );
int records = 10*1000;
clock_t ustart = clock();
for(int i = 0; i < records; i++) {
write(f, "012345678901234567890123456789" , 30 );
}
clock_t uend = clock();
close (f);
printf("no sync() seconds:%lf writes per second:%lf \n",
((double)(uend-ustart))/(CLOCKS_PER_SEC),
((double)records)/((double)(uend-ustart))/(CLOCKS_PER_SEC));
}
int main(int argc, const char * argv[])
{
withoutSync();
withSync();
return 0;
}
Linux buntu-1804 4.15.0-29-generic
no sync() seconds:0.024438 writes per second:0.00
sync() seconds:1.705764 writes per second:0.00
real3m6.475s
user0m0.006s
sys 0m1.725s
Linux ubuntu 4.4.0-87-generic
no sync() seconds:0.012887 writes per second:0.01
sync() seconds:0.736563 writes per second:0.00
real 0m8.945s
user0m0.016s
sys 0m0.732s
To manage notifications about this bug go to:
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[Kernel-packages] [Bug 1785020] Re: fsync is slow on later kernels with ext4 filesystms
Confirming the fix in in the latest kernel release, can you point in the
direction of the original bug, as I've not been able to find a reference to it.
--
You received this bug notification because you are a member of Kernel
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https://bugs.launchpad.net/bugs/1785020
Title:
fsync is slow on later kernels with ext4 filesystms
Status in linux package in Ubuntu:
Incomplete
Bug description:
So this is a simple one, if I run the following code (see below) on Ubuntu
18.04 (4.15.0-29-generic ) and against Ubuntu 16.04 ( 4.4.0-87-generic) I get
two different results ; The question is why? It seems that fsync may be broken
in the latest kernel and may well be broken as early as 4.10 ? This has huge
implications around performance sensitive applications like mysql.
It also so worth noting that I'm running this against an ext4 filesystem with
the following mount options
rw,noatime,nodiratime,nobarrier,data=journal
4.4.0-87-generic - # time ./fsync
real 0m7.537s <-
user 0m0.000s
sys 0m1.060s <-
4.15.0-29-generic - # time ./fsync
real 1m38.299s <-
user 0m0.013s
sys 0m0.893s <-
Linux buntu-1804 4.15.0-29-generic
no sync() seconds:0.024438 writes per second:0.00
sync() seconds:1.705764 writes per second:0.00
real3m6.475s
user0m0.006s
sys 0m1.725s
Linux ubuntu 4.4.0-87-generic
no sync() seconds:0.012887 writes per second:0.01
sync() seconds:0.736563 writes per second:0.00
real0m8.945s
user0m0.016s
sys 0m0.732s
#!/usr/bin/python
import os, sys, mmap
# Open a file
fd = os.open( "/a/testfile", os.O_RDWR|os.O_CREAT|os.O_DIRECT )
m = mmap.mmap(-1, 512)
for i in range (1,1):
os.lseek(fd,os.SEEK_SET,0)
m[1] = "1"
os.write(fd, m)
os.fsync(fd)
# Close opened file
os.close( fd )
#define _GNU_SOURCE
#include
#include
#include
#include
void withSync() {
int f = open( "/a/t8" , O_RDWR | O_CREAT |O_DIRECT );
lseek (f, 0, SEEK_SET );
int records = 10*1000;
clock_t ustart = clock();
for(int i = 0; i < records; i++) {
write(f, "012345678901234567890123456789" , 30);
fsync(f);
}
clock_t uend = clock();
close (f);
printf(" sync() seconds:%lf writes per second:%lf\n",
((double)(uend-ustart))/(CLOCKS_PER_SEC),
((double)records)/((double)(uend-ustart))/(CLOCKS_PER_SEC));
}
void withoutSync() {
int f = open( "/a/t10" , O_RDWR | O_CREAT | O_DIRECT );
lseek (f, 0, SEEK_SET );
int records = 10*1000;
clock_t ustart = clock();
for(int i = 0; i < records; i++) {
write(f, "012345678901234567890123456789" , 30 );
}
clock_t uend = clock();
close (f);
printf("no sync() seconds:%lf writes per second:%lf \n",
((double)(uend-ustart))/(CLOCKS_PER_SEC),
((double)records)/((double)(uend-ustart))/(CLOCKS_PER_SEC));
}
int main(int argc, const char * argv[])
{
withoutSync();
withSync();
return 0;
}
Linux buntu-1804 4.15.0-29-generic
no sync() seconds:0.024438 writes per second:0.00
sync() seconds:1.705764 writes per second:0.00
real3m6.475s
user0m0.006s
sys 0m1.725s
Linux ubuntu 4.4.0-87-generic
no sync() seconds:0.012887 writes per second:0.01
sync() seconds:0.736563 writes per second:0.00
real 0m8.945s
user0m0.016s
sys 0m0.732s
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1785020/+subscriptions
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[Kernel-packages] [Bug 1785020] Re: fsync is slow on later kernels with ext4 filesystms
Reports uploaded as requested bug status set to confirmed.
--
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1785020
Title:
fsync is slow on later kernels with ext4 filesystms
Status in linux package in Ubuntu:
Confirmed
Bug description:
So this is a simple one, if I run the following code (see below) on Ubuntu
18.04 (4.15.0-29-generic ) and against Ubuntu 16.04 ( 4.4.0-87-generic) I get
two different results ; The question is why? It seems that fsync may be broken
in the latest kernel and may well be broken as early as 4.10 ? This has huge
implications around performance sensitive applications like mysql.
It also so worth noting that I'm running this against an ext4 filesystem with
the following mount options
rw,noatime,nodiratime,nobarrier,data=journal
4.4.0-87-generic - # time ./fsync
real 0m7.537s <-
user 0m0.000s
sys 0m1.060s <-
4.15.0-29-generic - # time ./fsync
real 1m38.299s <-
user 0m0.013s
sys 0m0.893s <-
Linux buntu-1804 4.15.0-29-generic
no sync() seconds:0.024438 writes per second:0.00
sync() seconds:1.705764 writes per second:0.00
real3m6.475s
user0m0.006s
sys 0m1.725s
Linux ubuntu 4.4.0-87-generic
no sync() seconds:0.012887 writes per second:0.01
sync() seconds:0.736563 writes per second:0.00
real0m8.945s
user0m0.016s
sys 0m0.732s
#!/usr/bin/python
import os, sys, mmap
# Open a file
fd = os.open( "/a/testfile", os.O_RDWR|os.O_CREAT|os.O_DIRECT )
m = mmap.mmap(-1, 512)
for i in range (1,1):
os.lseek(fd,os.SEEK_SET,0)
m[1] = "1"
os.write(fd, m)
os.fsync(fd)
# Close opened file
os.close( fd )
#define _GNU_SOURCE
#include
#include
#include
#include
void withSync() {
int f = open( "/a/t8" , O_RDWR | O_CREAT |O_DIRECT );
lseek (f, 0, SEEK_SET );
int records = 10*1000;
clock_t ustart = clock();
for(int i = 0; i < records; i++) {
write(f, "012345678901234567890123456789" , 30);
fsync(f);
}
clock_t uend = clock();
close (f);
printf(" sync() seconds:%lf writes per second:%lf\n",
((double)(uend-ustart))/(CLOCKS_PER_SEC),
((double)records)/((double)(uend-ustart))/(CLOCKS_PER_SEC));
}
void withoutSync() {
int f = open( "/a/t10" , O_RDWR | O_CREAT | O_DIRECT );
lseek (f, 0, SEEK_SET );
int records = 10*1000;
clock_t ustart = clock();
for(int i = 0; i < records; i++) {
write(f, "012345678901234567890123456789" , 30 );
}
clock_t uend = clock();
close (f);
printf("no sync() seconds:%lf writes per second:%lf \n",
((double)(uend-ustart))/(CLOCKS_PER_SEC),
((double)records)/((double)(uend-ustart))/(CLOCKS_PER_SEC));
}
int main(int argc, const char * argv[])
{
withoutSync();
withSync();
return 0;
}
Linux buntu-1804 4.15.0-29-generic
no sync() seconds:0.024438 writes per second:0.00
sync() seconds:1.705764 writes per second:0.00
real3m6.475s
user0m0.006s
sys 0m1.725s
Linux ubuntu 4.4.0-87-generic
no sync() seconds:0.012887 writes per second:0.01
sync() seconds:0.736563 writes per second:0.00
real 0m8.945s
user0m0.016s
sys 0m0.732s
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1785020/+subscriptions
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[Kernel-packages] [Bug 1785020] Re: fsync is slow on later kernels with ext4 filesystms
** Attachment added: "Report from 16.04 host"
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1785020/+attachment/5170767/+files/apport.linux.GFuqdi.apport
** Changed in: linux (Ubuntu)
Status: Incomplete => Confirmed
--
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1785020
Title:
fsync is slow on later kernels with ext4 filesystms
Status in linux package in Ubuntu:
Confirmed
Bug description:
So this is a simple one, if I run the following code (see below) on Ubuntu
18.04 (4.15.0-29-generic ) and against Ubuntu 16.04 ( 4.4.0-87-generic) I get
two different results ; The question is why? It seems that fsync may be broken
in the latest kernel and may well be broken as early as 4.10 ? This has huge
implications around performance sensitive applications like mysql.
It also so worth noting that I'm running this against an ext4 filesystem with
the following mount options
rw,noatime,nodiratime,nobarrier,data=journal
4.4.0-87-generic - # time ./fsync
real 0m7.537s <-
user 0m0.000s
sys 0m1.060s <-
4.15.0-29-generic - # time ./fsync
real 1m38.299s <-
user 0m0.013s
sys 0m0.893s <-
Linux buntu-1804 4.15.0-29-generic
no sync() seconds:0.024438 writes per second:0.00
sync() seconds:1.705764 writes per second:0.00
real3m6.475s
user0m0.006s
sys 0m1.725s
Linux ubuntu 4.4.0-87-generic
no sync() seconds:0.012887 writes per second:0.01
sync() seconds:0.736563 writes per second:0.00
real0m8.945s
user0m0.016s
sys 0m0.732s
#!/usr/bin/python
import os, sys, mmap
# Open a file
fd = os.open( "/a/testfile", os.O_RDWR|os.O_CREAT|os.O_DIRECT )
m = mmap.mmap(-1, 512)
for i in range (1,1):
os.lseek(fd,os.SEEK_SET,0)
m[1] = "1"
os.write(fd, m)
os.fsync(fd)
# Close opened file
os.close( fd )
#define _GNU_SOURCE
#include
#include
#include
#include
void withSync() {
int f = open( "/a/t8" , O_RDWR | O_CREAT |O_DIRECT );
lseek (f, 0, SEEK_SET );
int records = 10*1000;
clock_t ustart = clock();
for(int i = 0; i < records; i++) {
write(f, "012345678901234567890123456789" , 30);
fsync(f);
}
clock_t uend = clock();
close (f);
printf(" sync() seconds:%lf writes per second:%lf\n",
((double)(uend-ustart))/(CLOCKS_PER_SEC),
((double)records)/((double)(uend-ustart))/(CLOCKS_PER_SEC));
}
void withoutSync() {
int f = open( "/a/t10" , O_RDWR | O_CREAT | O_DIRECT );
lseek (f, 0, SEEK_SET );
int records = 10*1000;
clock_t ustart = clock();
for(int i = 0; i < records; i++) {
write(f, "012345678901234567890123456789" , 30 );
}
clock_t uend = clock();
close (f);
printf("no sync() seconds:%lf writes per second:%lf \n",
((double)(uend-ustart))/(CLOCKS_PER_SEC),
((double)records)/((double)(uend-ustart))/(CLOCKS_PER_SEC));
}
int main(int argc, const char * argv[])
{
withoutSync();
withSync();
return 0;
}
Linux buntu-1804 4.15.0-29-generic
no sync() seconds:0.024438 writes per second:0.00
sync() seconds:1.705764 writes per second:0.00
real3m6.475s
user0m0.006s
sys 0m1.725s
Linux ubuntu 4.4.0-87-generic
no sync() seconds:0.012887 writes per second:0.01
sync() seconds:0.736563 writes per second:0.00
real 0m8.945s
user0m0.016s
sys 0m0.732s
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1785020/+subscriptions
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[Kernel-packages] [Bug 1785020] Re: fsync is slow on later kernels with ext4 filesystms
Add apport-collect reports from the test hosts as requested.
** Attachment added: "Report from 18.04 host"
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1785020/+attachment/5170766/+files/apport.linux.q19xjx94.apport
--
You received this bug notification because you are a member of Kernel
Packages, which is subscribed to linux in Ubuntu.
https://bugs.launchpad.net/bugs/1785020
Title:
fsync is slow on later kernels with ext4 filesystms
Status in linux package in Ubuntu:
Confirmed
Bug description:
So this is a simple one, if I run the following code (see below) on Ubuntu
18.04 (4.15.0-29-generic ) and against Ubuntu 16.04 ( 4.4.0-87-generic) I get
two different results ; The question is why? It seems that fsync may be broken
in the latest kernel and may well be broken as early as 4.10 ? This has huge
implications around performance sensitive applications like mysql.
It also so worth noting that I'm running this against an ext4 filesystem with
the following mount options
rw,noatime,nodiratime,nobarrier,data=journal
4.4.0-87-generic - # time ./fsync
real 0m7.537s <-
user 0m0.000s
sys 0m1.060s <-
4.15.0-29-generic - # time ./fsync
real 1m38.299s <-
user 0m0.013s
sys 0m0.893s <-
Linux buntu-1804 4.15.0-29-generic
no sync() seconds:0.024438 writes per second:0.00
sync() seconds:1.705764 writes per second:0.00
real3m6.475s
user0m0.006s
sys 0m1.725s
Linux ubuntu 4.4.0-87-generic
no sync() seconds:0.012887 writes per second:0.01
sync() seconds:0.736563 writes per second:0.00
real0m8.945s
user0m0.016s
sys 0m0.732s
#!/usr/bin/python
import os, sys, mmap
# Open a file
fd = os.open( "/a/testfile", os.O_RDWR|os.O_CREAT|os.O_DIRECT )
m = mmap.mmap(-1, 512)
for i in range (1,1):
os.lseek(fd,os.SEEK_SET,0)
m[1] = "1"
os.write(fd, m)
os.fsync(fd)
# Close opened file
os.close( fd )
#define _GNU_SOURCE
#include
#include
#include
#include
void withSync() {
int f = open( "/a/t8" , O_RDWR | O_CREAT |O_DIRECT );
lseek (f, 0, SEEK_SET );
int records = 10*1000;
clock_t ustart = clock();
for(int i = 0; i < records; i++) {
write(f, "012345678901234567890123456789" , 30);
fsync(f);
}
clock_t uend = clock();
close (f);
printf(" sync() seconds:%lf writes per second:%lf\n",
((double)(uend-ustart))/(CLOCKS_PER_SEC),
((double)records)/((double)(uend-ustart))/(CLOCKS_PER_SEC));
}
void withoutSync() {
int f = open( "/a/t10" , O_RDWR | O_CREAT | O_DIRECT );
lseek (f, 0, SEEK_SET );
int records = 10*1000;
clock_t ustart = clock();
for(int i = 0; i < records; i++) {
write(f, "012345678901234567890123456789" , 30 );
}
clock_t uend = clock();
close (f);
printf("no sync() seconds:%lf writes per second:%lf \n",
((double)(uend-ustart))/(CLOCKS_PER_SEC),
((double)records)/((double)(uend-ustart))/(CLOCKS_PER_SEC));
}
int main(int argc, const char * argv[])
{
withoutSync();
withSync();
return 0;
}
Linux buntu-1804 4.15.0-29-generic
no sync() seconds:0.024438 writes per second:0.00
sync() seconds:1.705764 writes per second:0.00
real3m6.475s
user0m0.006s
sys 0m1.725s
Linux ubuntu 4.4.0-87-generic
no sync() seconds:0.012887 writes per second:0.01
sync() seconds:0.736563 writes per second:0.00
real 0m8.945s
user0m0.016s
sys 0m0.732s
To manage notifications about this bug go to:
https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1785020/+subscriptions
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