From 5da784cce4308ae10a79e3c8c41b13fb9568e4e0 Mon Sep 17 00:00:00 2001 From: Constantine Shulyupin Date: Thu, 6 Sep 2018 15:37:06 +0300 Subject: 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 Signed-off-by: Miklos Szeredi --- fs/fuse/fuse_i.h | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) (limited to 'fs/fuse/fuse_i.h') diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index f5bdce84e766..3d578745c852 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -28,8 +28,11 @@ #include #include -/** Max number of pages that can be used in a single read request */ -#define FUSE_MAX_PAGES_PER_REQ 32 +/** Default max number of pages that can be used in a single read request */ +#define FUSE_DEFAULT_MAX_PAGES_PER_REQ 32 + +/** Maximum of max_pages received in init_out */ +#define FUSE_MAX_MAX_PAGES 256 /** Bias for fi->writectr, meaning new writepages must not be sent */ #define FUSE_NOWRITE INT_MIN @@ -525,6 +528,9 @@ struct fuse_conn { /** Maximum write size */ unsigned max_write; + /** Maxmum number of pages that can be used in a single request */ + unsigned int max_pages; + /** Input queue */ struct fuse_iqueue iq; -- cgit v1.2.3