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[Qemu-devel] Re: Speed up hack
From: |
Vladimir N. Oleynik |
Subject: |
[Qemu-devel] Re: Speed up hack |
Date: |
Tue, 18 May 2004 12:30:52 +0400 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040117 |
Hi, Fabrice.
> Can you estimate the speed gains ? I am especially interested by the
> poll() overhead.
I changed test/sha1.c for see production
-#define BUFSIZE 4096
+#define BUFSIZE 4096*16
+#define TEST 10
+
+#include <sys/time.h>
+#include <unistd.h>
int
main(int argc, char **argv)
{
SHA1_CTX ctx;
unsigned char hash[20], buf[BUFSIZE];
- int i;
+ int i, tn;
+ struct timeval tv, tv2;
+ int ts, tus;
+ double dt;
+ for(tn = 0; tn < TEST; tn++) {
+ gettimeofday(&tv, NULL);
for(i=0;i<BUFSIZE;i++)
- buf[i] = i;
+ buf[i] = i + tn;
- printf("SHA1=");
+ gettimeofday(&tv2, NULL);
+ ts = tv2.tv_sec - tv.tv_sec;
+ tus = tv2.tv_usec - tv.tv_usec;
+ dt = 1000000.0*ts;
+ dt += tus;
+ dt /= 1000000.0;
+ printf("dt=%.3f SHA1=", dt);
for(i=0;i<20;i++)
printf("%02x", hash[i]);
printf("\n");
+ }
My P4 2.6GHZ give ~ 1 sec per test, my qemu (softmmu) give:
without TICKS_BEFORE_POLL ~ 11.838 sec per test
withc TICKS_BEFORE_POLL=100 ~ 11.756 sec per test
Hmm. very little different :(
I give ~ 0.02 sec per test if set "static inline" for
cpu_get_real_ticks() and qemu_run_timers()
;-)
> For the rest, optimizing DMA_run() would be simpler
> and more efficient.
May be ;-)
--w
vodz
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