Date: Sat, 30 Jan 1999 13:26:29 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> Cc: net@FreeBSD.ORG Subject: Re: ping -f only 50 pkts/sec ? h Message-ID: <Pine.BSF.3.91.990130131800.15685A-100000@labinfo.iet.unipi.it> In-Reply-To: <78uv4d$fkv$1@rena.mat.uc.pt>
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[also posted to net@freebsd.org]
On 30 Jan 1999, Rui Pedro Mendes Salgueiro wrote:
> Rui Pedro Mendes Salgueiro <rps@rena.mat.uc.pt> wrote:
...
> > more testing) and I noticed that the -f option seems to be limited
> > to 50 pkts/sec:
...
> I think I found when the problem was introduced.
...
> I compiled the 1.36 version, tried it and:
...
> 10000 / 2.87 = ~3484 packets/sec.
> The 1.37 version :
...
> 9997 / (3*60 + 21.15) = ~49.699 packets/sec.
>
> The 1.37 version has the following comment:
> ----------------------------
> revision 1.37
> date: 1998/05/25 20:16:05; author: fenner; state: Exp; lines: +104 -81
> Use select() timeouts instead of SIGALRM to schedule packet transmission.
>
> I suspect that this is related.
definitely. I think that a select() with a non-zero timeout will sleep
for at least one tick (10ms); i suppose that if you compile a kernel
with HZ=1000 you'll see 500 pkts/s.
Because the manpage says
-f Flood ping. Outputs packets as fast as they come back or one
hundred times per second, whichever is more.
i think the 1.36 behaviour is the correct one. Can't comment on the fix
having not looked at the code.
cheers
luigi
-----------------------------------+-------------------------------------
Luigi RIZZO .
EMAIL: luigi@iet.unipi.it . Dip. di Ing. dell'Informazione
HTTP://www.iet.unipi.it/~luigi/ . Universita` di Pisa
TEL/FAX: +39-050-568.533/522 . via Diotisalvi 2, 56126 PISA (Italy)
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