I'm using Ubuntu with kernel 3.2.1, x86_64. I'm trying to benchmark a file system, and I want to limit the page cache size to avoid the file system cache taking up too much RAM, which would obviously improve performance (but would not reflect the results on systems with less memory).
Is there a way to do that? I've seen an option in some RHEL distribution for tuning /proc/sys/vm/pagecaches which seems to satisfy this, but I dont see anything useful in Ubuntu except dirty_background_ratio, which will only trigger flushing to disk, not more caching (so I can get a lot more sync I/O etc)
Thank you