On 2013-7-21 16:53, Willy Tarreau wrote:
Hi Godbach,
That's quite a good analysis. I'm realizing that durnig the development
of the algorithm, the maximum weight was 255, and it was later changed to
256. The test code that was used for this is still in tests/filltab25.c if
you're curious. It displays in which order servers are picked, and applies
random weight changes on the fly.
I carefully checked and for me we can set SRV_UWGHT_MAX to SRV_UWGHT_RANGE.
It will have the effect of limiting the maximum number of servers a full
weight to 4095 instead of 4128 (so please update the doc for this). It is
also used in the leastconn algorithm, and similarly, the effective max
number of connections per server without overflowing will be limited to
1048575 instead of 1052688 (this is not a big issue).
So yeah, please go ahead and send a fix for this by. Please also replace
4128 with 4095 in the documentation!
Best regards,
Willy
Hi Willy,
Do you mean that we set SRV_UWEIGHT_MAX to SRV_UWEIGHT_RANGE in function
fwrr_queue_by_weight for roundrobin and similar function for leastconn:
static inline void fwrr_queue_by_weight(struct eb_root *root, struct
server *s)
{
s->lb_node.key = SRV_EWGHT_MAX - s->eweight;
eb32_insert(root, &s->lb_node);
s->lb_tree = root;
}
Since I have done this before I sent the first mail, but the result was
still not as expected,
I want to know that the check you have done was a real test not only
code review. If so, I will
do the test again later and send the patch if it works well.
--
Best Regards,
Godbach
