Messages in this thread | | | From | kuznet@ms2 ... | Subject | Re: Problems with kernel-2.2.19-6.2.7 from RH update for 6.2 | Date | Thu, 23 Aug 2001 20:29:50 +0400 (MSK DST) |
| |
Hello!
> > Where? httpd does not connect(). > > For read/write. Although it is incorrect to compare as thttpd is serving = > more=20 > than one connect.
It is even worse. Useless operation in data path. read/write will return the error, if connection died in any case.
> > I see. If tuning is goal, it is right way. Amount of syscalls is the sa= > me > > as with alarm, but logic is cleaner. > > Logic with alarms will not work in multithreaded case.
I meaned _your_ logic is cleaner . :-)
> I assume that using SO_RCVTIME/SO_SNDTIME would be better in terms of=20 > performance.
Not very much. But code becomes simpler.
Select() is better sometimes, f.e. when program uses signals (and glibc uses signals _internally_ when multithreaded, breaking lots of things, do you know this? :-)). In this case you need to raclulate remaining time to restart poll/read/write, linux select returns it.
> layer to use sync IP...
What is "sync"?
> be (approximately)? if we assume that I have lots of connects which trans= > fers=20 > small amount of data in each (1-2K).
It depends. The advantage of read/write with SO_*TIMEO is that in all 100% of cases data arrive in time or you send immeadiately and appear in right place and do not waste cache and cycles to exit from select and to enter to read/write. Also, select() is pretty suboptimal.
Alexey - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |