Justin Schoeman wrote:
Eric Jorgensen wrote:
Justin Schoeman wrote:
1) I use reserfs on all my partitions, but I have not benchmarked it
against ext2 (or any of the others). On my Athlon 600, I get 13MByte/s
to disk without any problems (system load is around 12%). The raw disk
can maintain 28MB/s, but I think the real bottleneck is the PCI bus, not
the fs.
Say what? 32-bit 33mhz PCI has about 132 megabytes (not bits, bytes)
per second bandwidth. A TV card needs at most 1/4th of that. If the raw
i/o capability of your harddrive is 28MB/sec, it needs less than 1/4th
of that. Even accounting for overhead, and assuming you are running at
the hardware speeds of your capture card and hard disk, more than half
of the pci bandwidth wouldn't get utilized.
- Eric
I think Eric has a point. Even with you calculations below, I think the
bottleneck is you hard drive. Write rate is slower than read rate.
13MB/s write rate for a single disk is doing very well.
Ed.-T.
Well, you have:
1) capture card to main memory = 13MB/s
2) main memory to HDD = 13MB/s
3) other access (screen updates, etc.)
For a total of just over 26MB/s - the rest is consumed by bus
arbitration/contention/etc. Most desktop chipsets are not very
effiecient, and with multiple devices accessing the PCI bus they max out
at _much_ less than the theoretical maximum... Unfortunate, but it
happens.
-justin
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