linux_dsm_epyc7002/include/uapi
Constantine Shulyupin 5da784cce4 fuse: add max_pages to init_out
Replace FUSE_MAX_PAGES_PER_REQ with the configurable parameter max_pages to
improve performance.

Old RFC with detailed description of the problem and many fixes by Mitsuo
Hayasaka (mitsuo.hayasaka.hu@hitachi.com):
 - https://lkml.org/lkml/2012/7/5/136

We've encountered performance degradation and fixed it on a big and complex
virtual environment.

Environment to reproduce degradation and improvement:

1. Add lag to user mode FUSE
Add nanosleep(&(struct timespec){ 0, 1000 }, NULL); to xmp_write_buf in
passthrough_fh.c

2. patch UM fuse with configurable max_pages parameter. The patch will be
provided latter.

3. run test script and perform test on tmpfs
fuse_test()
{

       cd /tmp
       mkdir -p fusemnt
       passthrough_fh -o max_pages=$1 /tmp/fusemnt
       grep fuse /proc/self/mounts
       dd conv=fdatasync oflag=dsync if=/dev/zero of=fusemnt/tmp/tmp \
		count=1K bs=1M 2>&1 | grep -v records
       rm fusemnt/tmp/tmp
       killall passthrough_fh
}

Test results:

passthrough_fh /tmp/fusemnt fuse.passthrough_fh \
	rw,nosuid,nodev,relatime,user_id=0,group_id=0 0 0
1073741824 bytes (1.1 GB) copied, 1.73867 s, 618 MB/s

passthrough_fh /tmp/fusemnt fuse.passthrough_fh \
	rw,nosuid,nodev,relatime,user_id=0,group_id=0,max_pages=256 0 0
1073741824 bytes (1.1 GB) copied, 1.15643 s, 928 MB/s

Obviously with bigger lag the difference between 'before' and 'after'
will be more significant.

Mitsuo Hayasaka, in 2012 (https://lkml.org/lkml/2012/7/5/136),
observed improvement from 400-550 to 520-740.

Signed-off-by: Constantine Shulyupin <const@MakeLinux.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
2018-10-01 10:07:06 +02:00
..
asm-generic Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next 2018-08-15 15:04:25 -07:00
drm drm: add msm compressed format modifiers 2018-07-26 10:39:21 -04:00
linux fuse: add max_pages to init_out 2018-10-01 10:07:06 +02:00
misc ocxl: Add an IOCTL so userspace knows what OCXL features are available 2018-06-03 20:40:32 +10:00
mtd ubi: expose the volume CRC check skip flag 2018-08-15 00:25:21 +02:00
rdma qedr: Add user space support for SRQ 2018-08-14 16:31:54 -06:00
scsi
sound ASoC: uapi: fix sound/skl-tplg-interface.h userspace compilation errors 2018-08-14 15:08:07 +01:00
video
xen xen/gntdev: Add initial support for dma-buf UAPI 2018-07-26 23:05:14 -04:00