[src/trunk]: src Make FUSE socket buffer tunable

[manu <manu%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/19e56973f76e
branches:  trunk
changeset: 348433:19e56973f76e
user:      manu <manu%NetBSD.org@localhost>
date:      Tue Oct 18 15:06:17 2016 +0000

description:
Make FUSE socket buffer tunable

When dealing with high I/O throughput, we could run out of buffer
space if the filesystem was not consuming requests fast enough.
Here we slightly raise the buffer size, and we make it tunable
through the PERFUSE_BUFSIZE environment variable so that we can
cope with higher requirement later.

While there, document PERFUSE_OPTIONS environment variable.

diffstat:

 lib/libperfuse/libperfuse.3  |  17 ++++++++++++++++-
 lib/libperfuse/perfuse.c     |  40 +++++++++++++++++++++++++++++++++++-----
 usr.sbin/perfused/msg.c      |  40 ++++++++++++++++++++++++++++++++++------
 usr.sbin/perfused/perfused.8 |   8 +++++++-
 4 files changed, 92 insertions(+), 13 deletions(-)

diffs (202 lines):

diff -r 61d3e2f8120e -r 19e56973f76e lib/libperfuse/libperfuse.3
--- a/lib/libperfuse/libperfuse.3       Tue Oct 18 14:48:11 2016 +0000
+++ b/lib/libperfuse/libperfuse.3       Tue Oct 18 15:06:17 2016 +0000
@@ -1,4 +1,4 @@
-.\" $NetBSD: libperfuse.3,v 1.3 2011/05/10 12:14:37 njoly Exp $
+.\" $NetBSD: libperfuse.3,v 1.4 2016/10/18 15:06:17 manu Exp $
 .\"
 .\" Copyright (c) 2010 Emmanuel Dreyfus. All rights reserved.
 .\"
@@ -100,6 +100,21 @@
 .Fn perfuse_open
 handles control to the regular
 .Xr open 2 .
+.Sh ENVIRONMENT
+.Bl -tag -width Er
+.It Ev PERFUSE_OPTIONS
+Comma-separated values controlling the usage of some FUSE methods. Allowed
+values are
+.Li enable_access ,
+.Li disable_access ,
+.Li enable_creat ,
+.Li disable_creat .
+.It Ev PERFUSE_BUFSIZE
+Set the socket buffer sizes used for communication with the filesystem.
+This should be raised as operation throughput requires it. Default is 
+.Li 2162688
+bytes, which is enough to queue 16 FUSE packets of maximum 132 kB length.
+.El
 .Sh RETURN VALUES
 .Fn perfuse_mount
 returns a file descriptor to the
diff -r 61d3e2f8120e -r 19e56973f76e lib/libperfuse/perfuse.c
--- a/lib/libperfuse/perfuse.c  Tue Oct 18 14:48:11 2016 +0000
+++ b/lib/libperfuse/perfuse.c  Tue Oct 18 15:06:17 2016 +0000
@@ -1,4 +1,4 @@
-/*  $NetBSD: perfuse.c,v 1.37 2015/06/19 17:33:20 christos Exp $ */
+/*  $NetBSD: perfuse.c,v 1.38 2016/10/18 15:06:17 manu Exp $ */
 
 /*-
  *  Copyright (c) 2010-2011 Emmanuel Dreyfus. All rights reserved.
@@ -51,6 +51,7 @@
 
 static struct perfuse_state *init_state(void);
 static int get_fd(const char *);
+static uint32_t bufvar_from_env(const char *, const uint32_t);
 
 
 static struct perfuse_state *
@@ -146,6 +147,35 @@
 
 }
 
+static uint32_t 
+bufvar_from_env(name, defval)
+       const char *name;
+       const uint32_t defval;
+{
+       char valstr[1024];
+       uint32_t retval = defval;
+
+       if (getenv_r(name, valstr, sizeof(valstr)) != -1) {
+               long int val;
+               char *ep;
+
+               errno = 0;
+               val = (int)strtol(valstr, &ep, 10);
+               if (*valstr == '\0' || *ep != '\0')
+                       DWARNX("bad %s value \"%s\"", name, valstr);
+               else if (errno != 0)
+                       DWARN("bad %s value \"%s\"", name, valstr);
+               else if (val <= 0L ||
+                        (unsigned long int)val > (unsigned long int)UINT32_MAX)
+                       DWARNX("%s value %ld out of "
+                              "uint32_t bounds", name, val);
+               else
+                       retval = val;
+       }
+
+       return retval;
+}
+
 int
 perfuse_open(const char *path, int flags, mode_t mode)
 {
@@ -180,10 +210,10 @@
        }
 
        /*
-        * Set a buffer lentgh large enough so that any FUSE packet
+        * Set a buffer lentgh large enough so that enough FUSE packets
         * will fit.
         */
-       opt = (uint32_t)FUSE_BUFSIZE;
+       opt = bufvar_from_env("PERFUSE_BUFSIZE", 16 * FUSE_BUFSIZE);
        optlen = sizeof(opt);
        if (setsockopt(sv[0], SOL_SOCKET, SO_SNDBUF, &opt, optlen) != 0)
                DWARN("%s: setsockopt SO_SNDBUF to %d failed", __func__, opt);
@@ -211,10 +241,10 @@
        }
 
        /*
-        * Set a buffer lentgh large enough so that any FUSE packet
+        * Set a buffer lentgh large enough so that enough FUSE packets
         * will fit.
         */
-       opt = (uint32_t)(4 * FUSE_BUFSIZE);
+       opt = bufvar_from_env("PERFUSE_BUFSIZE", 16 * FUSE_BUFSIZE);
        optlen = sizeof(opt);
        if (setsockopt(sv[0], SOL_SOCKET, SO_SNDBUF, &opt, optlen) != 0)
                DWARN("%s: setsockopt SO_SNDBUF to %d failed", __func__, opt);
diff -r 61d3e2f8120e -r 19e56973f76e usr.sbin/perfused/msg.c
--- a/usr.sbin/perfused/msg.c   Tue Oct 18 14:48:11 2016 +0000
+++ b/usr.sbin/perfused/msg.c   Tue Oct 18 15:06:17 2016 +0000
@@ -1,4 +1,4 @@
-/*  $NetBSD: msg.c,v 1.22 2014/08/16 16:32:04 manu Exp $ */
+/*  $NetBSD: msg.c,v 1.23 2016/10/18 15:06:17 manu Exp $ */
 
 /*-
  *  Copyright (c) 2010 Emmanuel Dreyfus. All rights reserved.
@@ -43,11 +43,41 @@
 
 #include "perfused.h"
 
+static uint32_t bufvar_from_env(const char const *, const uint32_t);
 static int xchg_pb_inloop(struct puffs_usermount *a, struct puffs_framebuf *,
        int, enum perfuse_xchg_pb_reply);
 static int xchg_pb_early(struct puffs_usermount *a, struct puffs_framebuf *,
        int, enum perfuse_xchg_pb_reply);
 
+static uint32_t 
+bufvar_from_env(name, defval)
+       const char *name;
+       const uint32_t defval;
+{
+       char valstr[1024];
+       uint32_t retval = defval;
+
+       if (getenv_r(name, valstr, sizeof(valstr)) != -1) {
+               long int val;
+               char *ep;
+
+               errno = 0;
+               val = (int)strtol(valstr, &ep, 10);
+               if (*valstr == '\0' || *ep != '\0')
+                       DWARNX("bad %s value \"%s\"", name, valstr);
+               else if (errno != 0)
+                       DWARN("bad %s value \"%s\"", name, valstr);
+               else if (val <= 0L ||
+                        (unsigned long int)val > (unsigned long int)UINT32_MAX)
+                       DWARNX("%s value %ld out of "
+                              "uint32_t bounds", name, val);
+               else
+                       retval = val;
+       }
+
+       return retval;
+}
+
 int
 perfused_open_sock(void)
 {
@@ -80,15 +110,13 @@
        /*
         * Set a buffer lentgh large enough so that a few FUSE packets
         * will fit. 
-        * XXX We will have to find how many packets we need
         */
-       opt = 4 * FUSE_BUFSIZE;
+       opt = bufvar_from_env("PERFUSE_BUFSIZE", 16 * FUSE_BUFSIZE);
        if (setsockopt(s, SOL_SOCKET, SO_SNDBUF, &opt, sizeof(opt)) != 0)
-               DWARN("%s: setsockopt SO_SNDBUF to %d failed", __func__, opt);
+               DWARN("%s: setsockopt SO_SNDBUF = %d failed", __func__, opt);
 
-       opt = 4 * FUSE_BUFSIZE;
        if (setsockopt(s, SOL_SOCKET, SO_RCVBUF, &opt, sizeof(opt)) != 0)
-               DWARN("%s: setsockopt SO_RCVBUF to %d failed", __func__, opt);
+               DWARN("%s: setsockopt SO_RCVBUF = %d failed", __func__, opt);
 
        /*
         * Request peer credentials
diff -r 61d3e2f8120e -r 19e56973f76e usr.sbin/perfused/perfused.8
--- a/usr.sbin/perfused/perfused.8      Tue Oct 18 14:48:11 2016 +0000
+++ b/usr.sbin/perfused/perfused.8      Tue Oct 18 15:06:17 2016 +0000
@@ -1,4 +1,4 @@
-.\" $NetBSD: perfused.8,v 1.11 2012/01/29 11:32:23 wiz Exp $
+.\" $NetBSD: perfused.8,v 1.12 2016/10/18 15:06:17 manu Exp $
 .\"
 .\" Copyright (c) 2010 Emmanuel Dreyfus. All rights reserved.
 .\"
@@ -118,6 +118,12 @@
 Enable debug output only when receiving
 .Li SIGINFO .
 .El
+.Sh ENVIRONMENT
+See
+.Xr libperfuse 3
+for environment variables affecting
+.Nm
+behavior.
 .Sh SIGNALS
 .Bl -tag -width indent
 .It Dv SIGINFO