Once you create a checkpoint, restore using -drive
cache=writeback,file=YOUR_DISK_IMAGE option to load the benchmarks faster.

- Avadh

On Thu, May 19, 2011 at 5:34 PM, <[email protected]> wrote:

> Yes, Checkpoints in QEMU 0.14 are very slow. I was thinking of
> getting a fresh copy of Disk and do this process, if it helps.
>
> --ishwar
> ---- Original message ----
> >Date: Thu, 19 May 2011 17:13:49 -0700
> >From: avadh patel <[email protected]>
> >Subject: Re: [marss86-devel] Disk Image and checkpoint issues
> >To: Saurabh Gupta <[email protected]>
> >Cc: <[email protected]>
> >
> >   On Thu, May 19, 2011 at 4:58 PM, Saurabh Gupta
> >   <[email protected]> wrote:
> >
> >     avadh patel <avadh4all <at> gmail.com> writes:
> >
> >     >
> >     >
> >     > On Thu, May 19, 2011 at 10:51 AM, Saurabh Gupta
> >     <saurabg <at> gmail.com>
> >     wrote:
> >     >
> >     > Hi,
> >     > I have created the checkpoints for different
> >     benchmarks using
> >     > create_checkpoints.py. I do not want to run the
> >     benchmarks from
> >     > the beginning like the script given on github
> >     does. I let the
> >     > benchmark run for a while and then call
> >     create_checkpoint to
> >     > save the state of machine(VM running the
> >     benchmark). Now I
> >     > start the simulation by run_bench.py. I have
> >     couple of concerns
> >     > here:
> >     > 1. I use -kill-after-finish in qemu
> >     configuration input, so I
> >     > am worried if the disk image gets corrupted by
> >     that. I get
> >     > varied results if I run the same checkpoint
> >     again and again
> >     > from the same image. The variation is less when
> >     I use my backup
> >     > disk image with checkpoints in it every time I
> >     run it.
> >     >
> >     > Disks corruption depends on the type of
> >     benchmarks. If you are running
> >     > something that uses disk too much ('dedup' for
> >     example) then there
> >     > is a high chance that you'll get disk
> >     corruption. To avoid this best way
> >     >
> >     > to run these benchmarks is to use it like
> >     following:
> >     >
> >     > $ ./your_benchmark; ./kill_sim
> >     >
> >     > In this way the simulation will be killed after
> >     it completes the benchmark.
> >     >
> >     > There is some option in qemu to start in
> >     'read-only' mode where changes
> >     > to the disk are saved into some tmp file but I
> >     never got that working for me.
> >     > May be new 0.14 merge might work.
> >     >
> >     >
> >     >
> >     > 2. Is that correct that run_bench.py is running
> >     all the benchmarks
> >     > checkpoints at the same time? Sometimes I get
> >     results for all the
> >     > benchmarks, sometimes some of them do not
> >     finish, sometimes they
> >     > would finish but their stats file is corrupted.
> >     >
> >     > run_bench.py spawn the number of simulations in
> >     parallel as number of
> >     > disk images you provided in 'qemu_img' variable.
> >     >
> >     > About stats file corruption, there has been
> >     couple of small bug fixes in
> >     >
> >     > master branch about it, so update your code if
> >     you haven't.
> >     >
> >     > - Avadh
> >     >
> >     >
> >     >
> >     >
> >     > I am seeing all this weird behavior, has anyone
> >     else seen this?
> >     > or if someone can point out where I am going
> >     wrong?
> >     > Thanks.
> >     > -Saurabh
> >     >
> >
> _______________________________________________http://www.mars
> s86.org
> >     > Marss86-Devel mailing listMarss86-Devel <at>
> >
> cs.binghamton.eduhttps://www.cs.binghamton.edu/mailman/listinf
> o/marss86-devel
> >     >
> >     >
> >     >
> >     >
> >
> >     Hi,
> >
> >     Thanks for the suggestions, but I am confused now
> >     about the statement you
> >     made saying "run_bench.py spawn the number of
> >     simulations in parallel as
> >     number of disk images you provided in 'qemu_img'
> >     variable."
> >
> >     I think create_checkpoint.py creates all the
> >     checkpoints in the same disk
> >     image. Are you suggesting to have only one
> >     checkpoint to be created in one
> >     disk image for these purposes?
> >
> >     I have my all 10 benchmark checkpoints in the same
> >     image and I provide
> >     the path of this image to run_bench.py. It
> >     launches all the simulations
> >     at once from that. Do you think this is where I am
> >     going wrong? Because
> >     now all the simulations try to access the same
> >     image and modify it while
> >     it runs, leading to the behavior I am seeing right
> >     now.
> >
> >   in run_bench.py, 'qemu_img' is a variable that holds
> >   a list of images that contains
> >   all of your benchmark snapshots. Basically I copy a
> >   single image multiple times and
> >   put all these image names into this list to run
> >   benchmarks in parallel. If there is only
> >   one disk image name in 'qemu_img' then it will run
> >   all benchmarks in sequence.
> >   In case of only single disk image, it will run
> >   benchmarks in sequence and it won't
> >   corrupt the image.
> >   - Avadh
> >   P.S. Is anyone having issues with loadvm or savevm
> >   being 'too-slow' in qemu-0.14?
> >
> >
> >     -Saurabh
> >
> >     _______________________________________________
> >     http://www.marss86.org
> >     Marss86-Devel mailing list
> >     [email protected]
> >     https://www.cs.binghamton.edu/mailman/listinfo/marss86-
> devel
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