Re: memcpy_toio on i386 using byte writes even when n%2==0

H. Peter Anvin wrote:

For something that generates I/O transactions, it's imperative to
generate the smallest possible number of transactions.  Furthermore,
smaller than dword transactions aren't burstable, except at the
beginning and end of a burst.

Well, theoretically for writes they could be, if the memory region was prefetchable and the PCI chipset supported byte merge. It certainly isn't optimal however.

--
Robert Hancock      Saskatoon, SK, Canada
To email, remove "nospam" from [email protected]
Home Page: http://www.roberthancock.com/

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

---

• Follow-Ups:
  • Re: memcpy_toio on i386 using byte writes even when n%2==0
    • From: "H. Peter Anvin" <[email protected]>

• Prev by Date: Re: [RFC]disable msi mode in pci_disable_device
• Next by Date: Re: memcpy_toio on i386 using byte writes even when n%2==0
• Previous by thread: Re: memcpy_toio on i386 using byte writes even when n%2==0
• Next by thread: Re: memcpy_toio on i386 using byte writes even when n%2==0
• Index(es):
  • Date
  • Thread

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]