[lkml]   [2014]   [Sep]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: AHCI maximum transfer size
> Hi all,
> I searched the list and the internet for this question, but I did not
> find a definitive answer.
> I wonder what is the maximum AHCI transfer size for kernel 2.6.32.x
> Let me explain: using a command as "dd if=/dev/zero of=/dev/sda bs=2M" I
> can see, via iostat, that request-size is at 2M (as expected). However
> it seems to me that the effective transfer size is way lower: disabling
> writeback cache on the target disk, I see very low performance even for
> big-chunk transfers.
> Googling, I found this post on stackoverflow stating that maximum
> observerd AHCI transfer size (with a SATA protocol analyzer) is 128KB:
> The stackoverflow post seems to agree with this old article:
> Anyone has any idea of how to find (and eventually change) the used AHCI
> transfer size without touching the code?
> NOTE: please CC me directly.
> Regards.

Hi all,
any idea on the subject?


Danti Gionatan
Supporto Tecnico
Assyoma S.r.l. -
email: -
GPG public key ID: FF5F32A8

 \ /
  Last update: 2014-09-16 11:21    [W:0.061 / U:12.944 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site