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ahci & exynos5: avoid large DMA buf in AHCI bench 

Normally this bench has read all data to one large buffer and
than written it back to the drive but for SATA 3 (6 Gbps) benchmarks
we would need a buffer of approximately 1.2 GB to do it this way
and reach 2 seconds bench time. Thus we use a buffer of SATA request size
and override it with every request.
This commit is contained in:
Martin Stein 2013-06-25 18:18:41 +02:00 committed by Stefan Kalkowski
parent 0ad284febe
commit 3fb7e74287
1 changed files with 12 additions and 18 deletions
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30
os/src/drivers/ahci/exynos5/bench/main.cc
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@ -45,7 +45,11 @@ static void run_benchmark(Block::Driver &driver,
Operation &operation) Operation &operation)
{ {
using namespace Genode; using namespace Genode;
if (request_size > buffer_size) {
PERR("undersized buffer %u, need %u", buffer_size, buffer_size);
while (1) ;
}
size_t const block_count = request_size / driver.block_size();
/* /*
* The goal is to get a test that took 2 s < time < 2.3 s, * The goal is to get a test that took 2 s < time < 2.3 s,
* thus we start with count = 32 and then adjust the count * thus we start with count = 32 and then adjust the count
@ -55,26 +59,18 @@ static void run_benchmark(Block::Driver &driver,
unsigned ms = 0; unsigned ms = 0;
while (1) while (1)
{ {
/* calculate test parameters */
if (bytes > buffer_size) {
PERR("undersized buffer %u, need %u", buffer_size, bytes);
while (1) ;
}
size_t num_requests = bytes / request_size; size_t num_requests = bytes / request_size;
/* do measurement */ /* do measurement */
size_t const time_before_ms = timer.elapsed_ms(); unsigned const time_before_ms = timer.elapsed_ms();
for (size_t i = 0; i < num_requests; i++) for (unsigned i = 0; i < num_requests; i++)
{ {
size_t const block_count = request_size / driver.block_size(); addr_t const block_number = i * block_count;
addr_t const block_number = i*block_count;
operation(driver, block_number, block_count, operation(driver, block_number, block_count,
buffer_phys + i*request_size, buffer_phys, buffer_virt);
buffer_virt + i*request_size);
} }
/* read results */ /* read results */
size_t const time_after_ms = timer.elapsed_ms(); unsigned const time_after_ms = timer.elapsed_ms();
ms = time_after_ms - time_before_ms; ms = time_after_ms - time_before_ms;
/* /*
@ -121,7 +117,7 @@ int main(int argc, char **argv)
1048576, 262144, 16384, 8192, 4096, 2048, 1024, 512, 0 }; 1048576, 262144, 16384, 8192, 4096, 2048, 1024, 512, 0 };
/* total size of communication buffer */ /* total size of communication buffer */
size_t const buffer_size = 600*1024*1024; size_t const buffer_size = 1024*1024;
/* allocate read/write buffer */ /* allocate read/write buffer */
static Attached_ram_dataspace buffer(env()->ram_session(), buffer_size, static Attached_ram_dataspace buffer(env()->ram_session(), buffer_size,
@ -158,9 +154,7 @@ int main(int argc, char **argv)
/* /*
* Benchmark writing to SATA device * Benchmark writing to SATA device
* *
* We write back the content of the buffer, which we just filled during the * Attention: Original data will be overridden on target drive
* read benchmark. If both read and write succeed, the SATA device
* will retain its original content.
*/ */
printf("\n"); printf("\n");