Closed Bug 25108 Opened 20 years ago Closed 20 years ago

File download is slow on MAC


(Core :: Networking, defect, P1, critical)

Mac System 8.6





(Reporter: tever, Assigned: scc-obsolete)




(Keywords: perf, Whiteboard: [PDT+])

Overview Description:  ftp download's are very slow on the Mac.

Steps to Reproduce:
1.)  Go to an ftp site 
2.)  select a large file and download

Actual Results:  File downloads ok but very slowly 

Expected Results:  should download much quicker

Build Date & Platform Bug Found:
MAC OS8.6 2000012601
Additional Builds and Platforms Tested On:
NT and Linux work fine
I thought I'd add that it took almost 5 minutes to download a 9 Meg file.  On
NT, similar size files took 10 - 15 seconds.
Putting on M14 radar, and adding perf keyword.
Keywords: perf
Target Milestone: M14
putting on beta1 radar, per beta criteria priority #2 - performance
Keywords: beta1
Putting on PDT+ radar for beta1.
Whiteboard: [PDT+]
Try it now that the buffering is in place for file writes.
Whiteboard: [PDT+] → [PDT+] [02/18/00]
I have no clue on this one. waiting for testing to see if it's even a problem 
tever, is this an http problem too? file download in general on the mac?
I just tested the 2/10/00 build
4.7	gets about 380-450 k/s
M14   gets around 25-32 k/s
so I would say that there is still a significant performance gap.
definately! Thanks for testing david. One more thing :). I'm 99% sure this is 
not an FTP problem, can you try downloading an HTTP file 
( and report back your findings?
I got just about the same numbers where 4.7 was a bit slower at 350k/s and 
mozilla was stuck at 32k/s so I think you assumption that the bottleneck is 
outside of ftp is probably right.  
Changing summary from: "ftp download slow on Mac" 
Summary: ftp download slow on Mac → File download is slow on MAC
I think someone on dp's team (someone with a mac) should take this.
Assignee: valeski → dp
Scott said he would take this one.
Assignee: dp → scc
Does Scott have time to look at this right away? Other than writing some 
nsLocalFileMac stuff I don't have any other m14 stuff to look at if the tree is 
ever green enough to check in.
Scott can you update progress on this.
Obviously, if it's PDT+, it must also be a P1
Priority: P3 → P1
With advice from Simon, I'm using the Mac Instrumentation SDK.  So far nothing is 
standing out.  It's leaning towards looking like thread starvation.  David, if 
you want and/or have time to help with this, I could use any help you can 
provide.  Jim Roskind suggests an alternative is innappropriately sized buffers.  
Gagan favors the thread starvation theory.  I just need to get something in the 
profiling to prove or disprove any of these theories.
Whiteboard: [PDT+] [02/18/00] → [PDT+] [expected fix date unknown]
Need a more current ETA please?  Any new data?
Whiteboard: [PDT+] [expected fix date unknown] → [PDT+] [investigating]
The actual bug is that socket transport is choked on Macintosh by its current 
lack of pollable events.  This bug affects every byte that comes over the 
network, as far as I know, except for DNS lookups.  The real fix that will bring 
performance to 4.x levels (or perhaps _better_) is to implement pollable events 
on Mac.  In the meanwhile, changing the current poll timeout value from the 
initial guess of 250 msec to 5 msecs yields a substantial speed increase across 
the board.  The performance is typically 8-10x better.  This is most visible in 
file downloads using ftp (or any other protocol, for that matter), but also makes 
downloading ordinary web pages snappier.  UI responsiveness has not been 
compromised.  This fix does not bring performance to 4.x levels, but we are 
withing a factor of 2 or 3 now instead of 20.  I am now going to mark this bug as 
fixed.  Further work on implementing pollable events should be under a new bug, 
probably assigned to <>.  We believe this problem is also the 
root cause of his PDT+ bug #2611, which I would love to mark fixed as well.

File download is now significantly faster, and will be faster still after 
pollable events are implemented for Mac.
Closed: 20 years ago
Resolution: --- → FIXED
Whiteboard: [PDT+] [investigating] → [PDT+]
I cannot check this right now because of bug 29360
measuring around 14 seconds to download 6 megs.  Much better.
Mac OS8.6 2000022908
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