drop fs caches before each iteration

This commit is contained in:
Carl Pearson
2019-09-30 12:04:52 -05:00
parent 09e8757f72
commit cc92923509
2 changed files with 48 additions and 48 deletions

View File

@@ -61,6 +61,8 @@ g++ code_using_perfect.cpp -I perfect/include
## Tools Usage
### tools/perfect-cli
`perfect` provides some useful tools on Linux:
```
@@ -87,9 +89,9 @@ The basic usage is `tools/perfect-cli -- my-exe`, which will attempt to configur
Most modifications require elevated privileges.
The default behavior is to:
* disable ASLR
* drop filesystem caches
* set CPU performance to maximum
* disable CPU turbo
* drop filesystem caches before each iteration
Some options (all should provided before the `--` option):
* `--no-mod` flag will cause `perfect-cli` to not modify the system performance state
@@ -101,8 +103,41 @@ A common invocation might look like:
```
sudo tools/perfect-cli -n 5 --stderr=run.err --stdout=run.out -- ./my-benchmark
```
This will disable ASLR, set CPU performance to maximum, disable CPU turbo, drop FS caches, and then run `./my-benchmark` 5 times, redirecting stdout/stderr of ./my-benchmark to `run.out`/`run.err`.
This will disable ASLR, set CPU performance to maximum, disable CPU turbo, and then run `./my-benchmark` 5 times after dropping the filesystem cache before each run, redirecting stdout/stderr of ./my-benchmark to `run.out`/`run.err`.
The owner of `run.out` and `run.err` will be set to whichever user called `sudo`.
### tools/addr
Print the address of `main`, a stack variable, and a heap variable.
Useful for demoing ASLR.
### tools/no-aslr
Disable ASLR on the provided execution.
With ASLR, addresses are different with each invocation
```
$ tools/addr
main: 94685074364704
stack: 140734279743492
heap: 94685084978800
$ tools/addr
main: 93891046344992
stack: 140722671706708
heap: 93891068624496
```
Without ASLR, addresses are the same in each invocation
```
$ tools/no-aslr tools/addrs
main: 93824992233760
stack: 140737488347460
heap: 93824994414192
$ tools/no-aslr tools/addrs
main: 93824992233760
stack: 140737488347460
heap: 93824994414192
```
## API Usage
@@ -115,7 +150,7 @@ perfect::CpuTurboState state;
PERFECT(perfect::get_cpu_turbo_state(&state));
```
## Monitoring
### Monitoring
`perfect` can monitor and record GPU activity.
@@ -146,10 +181,6 @@ See [tools/no_aslr.cpp](tools/no_aslr.cpp)
* `Result set_aslr(const AslrState &state)`: set a previously-saved ASLR state
### Flush file system caches
`perfect` can drop various filesystem caches
@@ -238,40 +269,6 @@ See [examples/cpu_cache.cpp](examples/cpu_cache.cpp).
* `void flush_all(void *p, const size_t n)`: Flush all cache lines starting at `p` for `n` bytes.
## Tools
### tools/addr
Print the address of `main`, a stack variable, and a heap variable.
Useful for demoing ASLR.
### tools/no-aslr
Disable ASLR on the provided execution.
With ASLR, addresses are different with each invocation
```
$ tools/addr
main: 94685074364704
stack: 140734279743492
heap: 94685084978800
$ tools/addr
main: 93891046344992
stack: 140722671706708
heap: 93891068624496
```
Without ASLR, addresses are the same in each invocation
```
$ tools/no-aslr tools/addrs
main: 93824992233760
stack: 140737488347460
heap: 93824994414192
$ tools/no-aslr tools/addrs
main: 93824992233760
stack: 140737488347460
heap: 93824994414192
```
## Changelog