[User-mode-linux-devel] Fwd: Q: TCP_TW_RECYCLE_TICK for HZ == 10

[lars b. <la...@no...>]

This might be useful for 2.3.41.

From: ku...@ms...
Subject: Re: Q: TCP_TW_RECYCLE_TICK for HZ == 10
To: lar...@in... (lars brinkhoff)
Date: Tue, 1 Feb 2000 19:39:45 +0300 (MSK)
Cc: lin...@vg...

Hello!

> In 2.3.41, include/net/tcp.h says:
> 
> #if HZ == 100
> #define TCP_TW_RECYCLE_TICK (7+2-TCP_TW_RECYCLE_SLOTS_LOG)
> #elif HZ == 1024
> #define TCP_TW_RECYCLE_TICK (10+2-TCP_TW_RECYCLE_SLOTS_LOG)
> #else
> #error HZ != 100 && HZ != 1024.
> #endif
> 
> What should TCP_TW_RECYCLE_TICK be defined as for, say, HZ == 10?

TCP_TW_RECYCLE_TICK = (log(HZ)+2-TCP_TW_RECYCLE_SLOTS_LOG)

If HZ is not a 2^N, then it is rounded up to the closest power of two.
In your case it is:

#define TCP_TW_RECYCLE_TICK (4+2-TCP_TW_RECYCLE_SLOTS_LOG)

Alexey Kuznetsov