hi all,
Thank you for your advice ~
solution 2 definitly broaden my horizons ~~but may be not a good choice for
my project ~~LoL
i will try to mail freebsd-current mail list, if libc is as your description ,
may be i should modify it by myself ~~
Thank you so much~
Are u KingSoft's Dr Zhang ? nice to meet you !!!!!
winson sheng
winson sheng
From: Hongjiang Zhang
Date: 2016-12-23 11:44
To: 盛慧华; freebsd-net
Subject: RE: RE: question about fopen fd limit
Ok. I know.
There are two possible solutions:
Quick solution for short term: modify short to int in libc by yourself,
buildworld and installworld. Pushing to modify libc may take a long time,
especially only few people encounter this issue. You’d better send email to
freebsd-current to confirm whether they accept your suggestion.
Work around: You can first reserve a series of fd before opening TCP
connections. For example, invoke open(“/dev/null”) for 10000 times to get 10000
fds. Those fd values are small enough to be held by “short”. After that, start
TCP connections. Once you need to fopen a file, please call open(“xxx”)
instead, and then use dup2(old_fd, new_fd) to exchange the two fd. The old_fd
value is the one obtained by open(“xxx”), and new_fd is one in your reserved fd
fields, and next please use fdopen(fd, mode). Here, you have to manage the
reserved fds by yourself including open/close.
In my eyes:
is the quick method, and there is no modifications in your logic.
Needs you to maintain the reserved consecutive fields for fd by yourself, which
increased the complexity of your logic.
Thanks
Hongjiang Zhang
From: 盛慧华 [mailto:hhsh...@corp.netease.com]
Sent: Friday, December 23, 2016 11:02 AM
To: Hongjiang Zhang <honz...@microsoft.com>; freebsd-net
<freebsd-net@freebsd.org>
Subject: Re: RE: question about fopen fd limit
hi all,
not map TCP to FILE, you misunderstanding my meaning~
for example, if my server tcp already holds 32000 connection
fopen only has 767 fd to use
the problem has no bussiness with tcp fd, BUT fopen ...
in some particular situlations , my server will open 1k+ FILE , that will exceed the fileno limit, and overflow occur
my server can't open any file more ,that's the problem ~
so i felt if bsd official could change FILE struct's fileno to a UNSIGNED SHORT that may be an effecient and convenient solution just for my case ?
UNSIGNED SHORT fileno is enough for me, and i don't wanna change a lot of
FILE function that take FILE * as its argument ~
Thank you ~~~
winson sheng
winson sheng
From: Hongjiang Zhang
Date: 2016-12-23 10:17
To: 盛慧华; freebsd-net
Subject: RE: question about fopen fd limit
Why do you need to map TCP fd to FILE?
It is difficult to modify FILE structure. If it is possible, let us figure out some new designs to meet your requirement.
-----Original Message-----
From: owner-freebsd-...@freebsd.org [mailto:owner-freebsd-...@freebsd.org] On
Behalf Of ???
Sent: Thursday, December 22, 2016 11:57 PM
To: freebsd-net <freebsd-net@freebsd.org>
Subject: question about fopen fd limit
hi all,
hi~
we are from Chinese Game Develop Corp, Netease.
and One of our product using FreeBsd as its OS platform.
This Game has Millions of players online , and Each Server may holds 25000+
tcp connection at the same time.Thanks to BSD and kqueue :)
for example, it's one of our server , netstat cmd to list connections overall...
netstat -an | grep 13396 (it's our listening port) | wc -l
23221
recently we do some performance optimize and promote this connect limit to 28000+ or 30000+.
But we find Freebsd has a limit that this huge online number will take
28000+ fd, and bsd FILE * struct's
fd only support to SHORT . such as ..
struct __sFILE {
...
short _file; /* (*) fileno, if Unix descriptor, else -1 */ ...
so if our server want to fopen some file when we still hold this online number, the fd amount may easily exceed 32767, and fopen definitely return a err code. then the server will appear some fataly ERROR.
we do a simple test and confirm this situation.
then in fopen's code , we notice that we can use open to return a fd instread of fopen to avoid this overflow,
as below
68 /*
1 * File descriptors are a full int, but _file is only a short.
2 * If we get a valid file descriptor that is greater than
3 * SHRT_MAX, then the fd will get sign-extended into an
4 * invalid file descriptor. Handle this case by failing the
5 * open.
6 */
BUT ... so many c lib FILE series function needs a FILE * pointer as input argument, we can't convert all of them to fd, or it will be a rather suffering things to us.
and even in BSD 10 , it seems this short limit still there , but other OS as debian , FILE strucnt's fileno is a int .
we found an unoffical patch easily change this fileno to unsigned , but we are a very stready project, we can't afford the risk to use an unoffical patch.
so, do you have any plan to change this fopen fd limit to UNSIGNED SHORT or int in the future ? ushort is enough for us .
if you do , we are really glad and excited~~~~~~~if you don't ,it donen't
matter, plz give us a reply so that we may need to
find some other plan to resolved this suffering thing.
LoL, thank you !!!!!
yours sincerely
winson sheng
winson sheng
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