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ab8f55b9fd
freebsd-nq/sys
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Scott Long ab8f55b9fd Add a sysctl vfs.read_min to complement the exiting vfs.read_max. It 
defaults to 1, meaning that it's off.

When read-ahead is enabled on a file, the vfs cluster code deliberately
breaks a read into 2 I/O transactions; one to satisfy the actual read,
and one to perform read-ahead.  This makes sense in low-latency
circumstances, but often produces unbalanced i/o transactions that
penalize disks.  By setting vfs.read_min, we can tell the algorithm to
fetch a larger transaction that what we asked for, achieving the same
effect as the read-ahead but without the doubled, unbalanced transaction
and the slightly lower latency.  This significantly helps our workloads
with video streaming.

Submitted by:	emax
Reviewed by:	kib
Obtained from:	Netflix
2013-05-07 08:16:21 +00:00
..
amd64 Switch to standard copyright license text 2013-05-02 12:35:15 +00:00
arm decode_win_sdram_fixup() function should be declared, defined and used 2013-05-07 06:42:07 +00:00
boot Move initialization of CESA decoding windows from common section 2013-05-06 13:34:36 +00:00
bsm Implement chflagsat(2) system call, similar to fchmodat(2), but operates on 2013-03-21 22:59:01 +00:00
cam Rework r250298 in more correct way. 2013-05-06 16:50:39 +00:00
cddl In case ZFS doesn't use UMA for buffers there's no need to waste memory 2013-05-01 17:34:44 +00:00
compat Regenerate files for pipe2(). 2013-05-01 22:45:04 +00:00
conf Allow the default USB template to be specified at compile time. 2013-05-03 08:19:09 +00:00
contrib Expose cvmx_mgmt_port_num_ports() as a wrapper to the static 2013-05-02 19:45:53 +00:00
crypto When porting XTS-related code from OpenBSD I forgot to update copyright (only 2013-02-20 22:59:53 +00:00
ddb
dev Re-work how transmit buffer limits are enforced - partly to fix the PR, 2013-05-07 07:52:18 +00:00
fs Avoid deactivating the page if it is already on a queue, only requeue 2013-05-06 21:04:42 +00:00
gdb
geom - Use int8_t type for the mftrecsz field in g_label_ntfs. char type 2013-05-05 08:00:16 +00:00
gnu/fs/reiserfs Garbage collect XFS bits which are now already completely disconnected 2013-03-02 15:33:54 +00:00
i386 Remove redundant definitions of _ALIGN and _ALIGNBYTES. 2013-04-21 11:12:44 +00:00
ia64 Remove ctl(4) from GENERIC. Also remove 'options CTL_DISABLE' 2013-04-12 16:25:03 +00:00
isa
kern Add a sysctl vfs.read_min to complement the exiting vfs.read_max. It 2013-05-07 08:16:21 +00:00
kgssapi Isilon reported that sec=krb5p NFS mounts had a problem when m_len == 0 2013-05-01 22:07:55 +00:00
libkern Attempt to mitigate poor initialization of arc4 by one-shot 2013-04-19 00:30:52 +00:00
mips Use cvmx_mgmt_port_num_ports() instead of the inlined copy of a 2013-05-02 19:47:36 +00:00
modules Add the AR9300 HAL into the kernel and module builds. 2013-05-02 07:05:34 +00:00
net Back out r249318, r249320 and r249327 due to a heisenbug most 2013-05-06 16:42:18 +00:00
net80211 Add const qualifier to the dst parameter of the ifnet if_output method. 2013-04-26 12:50:32 +00:00
netatalk Add const qualifier to the dst parameter of the ifnet if_output method. 2013-04-26 12:50:32 +00:00
netgraph Add const qualifier to the dst parameter of the ifnet if_output method. 2013-04-26 12:50:32 +00:00
netinet Back out r249318, r249320 and r249327 due to a heisenbug most 2013-05-06 16:42:18 +00:00
netinet6 Use FF02:0:0:0:0:2:FF00::/104 prefix for IPv6 Node Information Group 2013-05-04 19:16:26 +00:00
netipsec Use IP6STAT_INC/IP6STAT_DEC macros to update ip6 stats. 2013-04-09 07:11:22 +00:00
netipx
netnatm
netpfil Improve KASSERT() message. 2013-05-06 21:44:06 +00:00
netsmb If the kernel is compiled with VMIMAGE support, the first attempt of 2013-05-04 16:55:48 +00:00
nfs Move the NFS FHA (File Handle Affinity) code from sys/nfsserver to 2013-04-17 22:42:43 +00:00
nfsclient When an NFS unmount occurs, once vflush() writes the last dirty 2013-04-18 23:20:16 +00:00
nfsserver Move the NFS FHA (File Handle Affinity) code from sys/nfsserver to 2013-04-17 22:42:43 +00:00
nlm
ofed Add const qualifier to the dst parameter of the ifnet if_output method. 2013-04-27 08:11:48 +00:00
opencrypto When porting XTS-related code from OpenBSD I forgot to update copyright (only 2013-02-20 22:59:53 +00:00
pc98 - Correct mispellings of word resource 2013-04-17 11:47:32 +00:00
pci - Corrrect mispellings of word useful 2013-04-17 11:45:15 +00:00
powerpc Only check fan type once. Not only is continuously rechecking pointless, a 2013-05-05 22:42:10 +00:00
rpc Fix a potential socket leak in the NFS server. If a client closes its 2013-04-08 19:03:01 +00:00
security Switch the vm_object mutex to be a rwlock. This will enable in the 2013-03-09 02:32:23 +00:00
sparc64 Remove ctl(4) from GENERIC. Also remove 'options CTL_DISABLE' 2013-04-12 16:25:03 +00:00
sys Back out r249318, r249320 and r249327 due to a heisenbug most 2013-05-06 16:42:18 +00:00
teken
tools Further refine the handling of stop signals in the NFS client. The 2013-02-21 19:02:50 +00:00
ufs - Correct mispellings of the word occurrence 2013-04-17 11:40:10 +00:00
vm Optimize vm_radix_lookup_ge() and vm_radix_lookup_le(). Specifically, 2013-05-04 22:50:15 +00:00
x86 Introduce kern.timecounter.smp_tsc_adjust tunable (disabled by default) and 2013-04-18 17:07:04 +00:00
xdr Use m_get() and m_getcl() instead of compat macros. 2013-03-15 10:21:18 +00:00
xen xenstore/xenstore.c: 2013-04-29 23:08:13 +00:00
Makefile Remove netncp cscope entry missed in r248097 2013-03-12 14:21:52 +00:00