[syslinux] Problem with 90MB Initrd

[Gene Cumm]

Yes, and far more than enough to see IO rate decay.

On Wed, Sep 30, 2015 at 9:36 AM, H. Peter Anvin <hpa at zytor.com> wrote:
> 76 MB would be less than the rollover threshold.
>
> On September 30, 2015 3:45:23 AM PDT, Gene Cumm <gene.cumm at gmail.com> wrote:
>>On Wed, Sep 23, 2015 at 4:58 PM, Gene Cumm <gene.cumm at gmail.com> wrote:
>>> On Wed, Sep 23, 2015 at 4:24 PM, Patrick Masotta
>><masottaus at yahoo.com> wrote:
>>>>>>>
>>>>
>>>>  > BTW if you take a minute and read the first report
>>>>  > https://communities.vmware.com/message/2536774
>>>>  > You'll realize that VMWare TFTP "surprisingly" does not present
>>slow TFTP transfers
>>>>  > when they are driven by MS "bootmgfw.efi"; instead the problem is
>>only shown when
>>>>  > transfers are driven by syslinux.efi; At the moment, despite
>>probably VMware not handling
>>>>  > the net driver "polling" correctly, I started to wonder if "we"
>>are really handling the EFI Event
>>>>  > engine correctly when performing TFTP transfers within
>>syslinux.efi
>>>>  >
>>>>
>>>>  It might be a difference
>>>>  between using the TFTP and using the UDP
>>>>  interfaces, or somesuch.
>>>>
>>>>      -hpa
>>>>  <<<
>>>>
>>>> Sure "bootmgfw.efi" is doing something better than we do about TFTP
>>transfers.
>>>> They:
>>>> 1) do not rely on Service Binding Protocols then old EFI firmware
>>PCs do not complain.
>>>> 2) I think they do better when handling EFI Events and Timers.
>>>>
>>>> The key to see how they do what they do is this bootmgfw.efi
>>function:
>>>> TftppGetImageRegular
>>>> but the task is time consuming; efi environment functions are only
>>referenced by an index
>>>> on a pointer table then knowing what functions they are really
>>calling is not very easy
>>>> to see.
>>>
>>> My current inclination is that there's a bug in Syslinux's TFTP+UDP
>>> implementation.  If it's in the TFTP implementation, lpxelinux.0
>>> should also exhibit issues with larger files (which I seem to recall
>>> but can't be certain at the moment).
>>
>>lpxelinux.0 seems clear of this issue.  I did a transfer of ~76MB and
>>didn't see any decay.  I'm thinking either UDP or memory allocation
>>bug/misuse.
>
> --
> Sent from my Android device with K-9 Mail. Please excuse my brevity.



-- 
-Gene