lkml.org 
[lkml]   [2005]   [Sep]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] reorder struct files_struct
Eric Dumazet wrote:

> Hi
>
> Browsing (and using) the excellent RCU infrastructure for files that
> was adopted for 2.6.14-rc1, I noticed that the file_lock spinlock sit
> close to mostly read fields of 'struct files_struct'
>
> In SMP (and NUMA) environnements, each time a thread wants to open or
> close a file, it has to acquire the spinlock, thus invalidating the
> cache line containing this spinlock on other CPUS. So other threads
> doing read()/write()/... calls that use RCU to access the file table
> are going to ask further memory (possibly NUMA) transactions to read
> again this memory line.
>
> Please consider applying this patch. It moves the spinlock to another
> cache line, so that concurrent threads can share the cache line
> containing 'count' and 'fdt' fields.


How was the performance impact of this change measured?

Thanx...

ps
-
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/

\
 
 \ /
  Last update: 2005-09-14 23:45    [W:0.167 / U:0.100 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site