search for: 256kilo

...-------------- Suggestion to address all above comments: 1. allocate a bunch of pages and link them up, calculating the min and the max pfn. if max-min exceeds the allocated bitmap size, tell host. 2. limit allocated bitmap size to something reasonable. How about 32Kbytes? This is 256kilo bit in the map, which comes out to 1Giga bytes of memory in the balloon. ------------------------------------------------------------------------------------- Because the PFNs of the allocated pages are not linear increased, so 3 transmissions are impossible. Liang > > > the call...

...-------------- Suggestion to address all above comments: 1. allocate a bunch of pages and link them up, calculating the min and the max pfn. if max-min exceeds the allocated bitmap size, tell host. 2. limit allocated bitmap size to something reasonable. How about 32Kbytes? This is 256kilo bit in the map, which comes out to 1Giga bytes of memory in the balloon. ------------------------------------------------------------------------------------- Because the PFNs of the allocated pages are not linear increased, so 3 transmissions are impossible. Liang > > > the call...

...the call count of madvise: 42 Maybe the result will be worse if the guest is not idle, or the guest has more RAM. Do you want more data? Is it worth to do that? Liang > > > > > 2. limit allocated bitmap size to something reasonable. > > > How about 32Kbytes? This is 256kilo bit in the map, which comes > > > out to 1Giga bytes of memory in the balloon. > > > > So, even the VM has 1TB of RAM, the page bitmap will take 32MB of > memory. > > Maybe it's better to use a big page bitmap the save the pages > > allocated by balloon,...

...the call count of madvise: 42 Maybe the result will be worse if the guest is not idle, or the guest has more RAM. Do you want more data? Is it worth to do that? Liang > > > > > 2. limit allocated bitmap size to something reasonable. > > > How about 32Kbytes? This is 256kilo bit in the map, which comes > > > out to 1Giga bytes of memory in the balloon. > > > > So, even the VM has 1TB of RAM, the page bitmap will take 32MB of > memory. > > Maybe it's better to use a big page bitmap the save the pages > > allocated by balloon,...

...ddress all above comments: > 1. allocate a bunch of pages and link them up, > calculating the min and the max pfn. > if max-min exceeds the allocated bitmap size, > tell host. > 2. limit allocated bitmap size to something reasonable. > How about 32Kbytes? This is 256kilo bit in the map, which comes > out to 1Giga bytes of memory in the balloon. > ------------------------------------------------------------------------------------- > Because the PFNs of the allocated pages are not linear increased, so 3 transmissions > are impossible. > > &g...

...; > 1. allocate a bunch of pages and link them up, > > calculating the min and the max pfn. > > if max-min exceeds the allocated bitmap size, > > tell host. > > 2. limit allocated bitmap size to something reasonable. > > How about 32Kbytes? This is 256kilo bit in the map, which comes > > out to 1Giga bytes of memory in the balloon. > > ---------------------------------------------------------------------- > > --------------- Because the PFNs of the allocated pages are not linear > > increased, so 3 transmissions are impos...

...; > 1. allocate a bunch of pages and link them up, > > calculating the min and the max pfn. > > if max-min exceeds the allocated bitmap size, > > tell host. > > 2. limit allocated bitmap size to something reasonable. > > How about 32Kbytes? This is 256kilo bit in the map, which comes > > out to 1Giga bytes of memory in the balloon. > > ---------------------------------------------------------------------- > > --------------- Because the PFNs of the allocated pages are not linear > > increased, so 3 transmissions are impos...

...d for > > performance improvement. Right? > > It's a tradeoff for sure. Measure it, see what the overhead is. OK, I will try and get back to you. > > > > > > 2. limit allocated bitmap size to something reasonable. > > > How about 32Kbytes? This is 256kilo bit in the map, which comes > > > out to 1Giga bytes of memory in the balloon. > > > > So, even the VM has 1TB of RAM, the page bitmap will take 32MB of > memory. > > Maybe it's better to use a big page bitmap the save the pages > > allocated by balloon,...

...d for > > performance improvement. Right? > > It's a tradeoff for sure. Measure it, see what the overhead is. OK, I will try and get back to you. > > > > > > 2. limit allocated bitmap size to something reasonable. > > > How about 32Kbytes? This is 256kilo bit in the map, which comes > > > out to 1Giga bytes of memory in the balloon. > > > > So, even the VM has 1TB of RAM, the page bitmap will take 32MB of > memory. > > Maybe it's better to use a big page bitmap the save the pages > > allocated by balloon,...

...s more RAM. > Do you want more data? > > Is it worth to do that? > > Liang Either my math is wrong or there's an implementation bug. > > > > > > > 2. limit allocated bitmap size to something reasonable. > > > > How about 32Kbytes? This is 256kilo bit in the map, which comes > > > > out to 1Giga bytes of memory in the balloon. > > > > > > So, even the VM has 1TB of RAM, the page bitmap will take 32MB of > > memory. > > > Maybe it's better to use a big page bitmap the save the pages > &g...

...ed pages are across a wide range and the max-min > limit is very frequently to be true. Then, there will be many times of virtio transmission and it's bad for performance improvement. Right? > 2. limit allocated bitmap size to something reasonable. > How about 32Kbytes? This is 256kilo bit in the map, which comes > out to 1Giga bytes of memory in the balloon. So, even the VM has 1TB of RAM, the page bitmap will take 32MB of memory. Maybe it's better to use a big page bitmap the save the pages allocated by balloon, and split the big page bitmap to 32K bytes unit, then...

...ed pages are across a wide range and the max-min > limit is very frequently to be true. Then, there will be many times of virtio transmission and it's bad for performance improvement. Right? > 2. limit allocated bitmap size to something reasonable. > How about 32Kbytes? This is 256kilo bit in the map, which comes > out to 1Giga bytes of memory in the balloon. So, even the VM has 1TB of RAM, the page bitmap will take 32MB of memory. Maybe it's better to use a big page bitmap the save the pages allocated by balloon, and split the big page bitmap to 32K bytes unit, then...

...ch of pages and link them up, > > > calculating the min and the max pfn. > > > if max-min exceeds the allocated bitmap size, > > > tell host. > > > 2. limit allocated bitmap size to something reasonable. > > > How about 32Kbytes? This is 256kilo bit in the map, which comes > > > out to 1Giga bytes of memory in the balloon. > > > ---------------------------------------------------------------------- > > > --------------- Because the PFNs of the allocated pages are not linear > > > increased, so 3 tran...

...t? > > > > It's a tradeoff for sure. Measure it, see what the overhead is. > > OK, I will try and get back to you. > > > > > > > > > > 2. limit allocated bitmap size to something reasonable. > > > > How about 32Kbytes? This is 256kilo bit in the map, which comes > > > > out to 1Giga bytes of memory in the balloon. > > > > > > So, even the VM has 1TB of RAM, the page bitmap will take 32MB of > > memory. > > > Maybe it's better to use a big page bitmap the save the pages > &g...

...t zone *zone) Suggestion to address all above comments: 1. allocate a bunch of pages and link them up, calculating the min and the max pfn. if max-min exceeds the allocated bitmap size, tell host. 2. limit allocated bitmap size to something reasonable. How about 32Kbytes? This is 256kilo bit in the map, which comes out to 1Giga bytes of memory in the balloon. > -- > 1.9.1

...t; Then, there will be many times of virtio transmission and it's bad for performance > improvement. Right? It's a tradeoff for sure. Measure it, see what the overhead is. > > > 2. limit allocated bitmap size to something reasonable. > > How about 32Kbytes? This is 256kilo bit in the map, which comes > > out to 1Giga bytes of memory in the balloon. > > So, even the VM has 1TB of RAM, the page bitmap will take 32MB of memory. > Maybe it's better to use a big page bitmap the save the pages allocated by balloon, > and split the big page bitmap...

The implementation of the current virtio-balloon is not very efficient, Bellow is test result of time spends on inflating the balloon to 3GB of a 4GB idle guest: a. allocating pages (6.5%, 103ms) b. sending PFNs to host (68.3%, 787ms) c. address translation (6.1%, 96ms) d. madvise (19%, 300ms) It takes about 1577ms for the whole inflating process to complete. The test shows that the bottle neck

The implementation of the current virtio-balloon is not very efficient, Bellow is test result of time spends on inflating the balloon to 3GB of a 4GB idle guest: a. allocating pages (6.5%, 103ms) b. sending PFNs to host (68.3%, 787ms) c. address translation (6.1%, 96ms) d. madvise (19%, 300ms) It takes about 1577ms for the whole inflating process to complete. The test shows that the bottle neck