Re: [PATCH RFC V2 2/2] net: Optimize snmp stat aggregation by walking all the percpu data at once

From: Raghavendra K T
Date: Sat Aug 29 2015 - 03:52:05 EST

On 08/29/2015 08:56 AM, Eric Dumazet wrote:
On Sat, 2015-08-29 at 08:27 +0530, Raghavendra K T wrote:

/* Use put_unaligned() because stats may not be aligned for u64. */
put_unaligned(items, &stats[0]);

for (i = 1; i < items; i++)
- put_unaligned(snmp_fold_field64(mib, i, syncpoff), &stats[i]);
+ put_unaligned(buff[i], &stats[i]);

I believe Joe suggested following code instead :

buff[0] = items;
memcpy(stats, buff, items * sizeof(u64));

Thanks. Sure, will use this.

(I missed that. I thought that it was applicable only when we have
aligned data,and for power, put_aunaligned was not a nop unlike intel).

Also please move buff[] array into __snmp6_fill_stats64() to make it
clear it is used in a 'leaf' function.


(even if calling memcpy()/memset() makes it not a leaf function)

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